Biomolecule preconcentrator

Abstract

An evaporation device includes a sample fluid channel extending from a sample fluid inlet to a sample fluid outlet. The evaporation device is configured to evaporate a solvent of a sample fluid containing a target analyte to increase the concentration of the target analyte. The device includes a housing enclosing and defining a testing environment within which the evaporation device is disposed. The housing includes a heater, a temperature sensor, and a humidity sensor. A pump coupled to a gas inlet tube is configured to cause a gas flow within the testing environment adjacent to the evaporation device. A controller in communication with each of the heater, the temperature sensor, and the humidity sensor, is configured to activate the heater in response to at least one of a temperature value or a humidity value of the testing environment.

Description

Attorney Docket No.10046-586WO1 BIOMOLECULE PRECONCENTRATOR CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No.63 / 677,035, filed July 30, 2024, the entire contents of which are hereby incorporated by reference. BACKGROUND

[0002] The present disclosure relates generally to the detection of analytes from a sample. Detecting certain substances in a sample may be difficult when they are present in small quantities or concentrations. Often, detection of a particular analyte requires expensive and time-consuming processes. Some existing devices and systems cannot detect low concentrations of certain analytes (e.g., if they are below device’s detection limit, or there is a large error in quantification if near the detection limit). Furthermore, existing devices and systems fail to provide for portable, point-of-care, and continuous measurement devices capable of accurate detection of low concentrations.

[0003] A need exists for devices and systems capable of low-concentration analyte detection in a fast and efficient manner. SUMMARY

[0004] According to one implementation, a preconcentration system is disclosed including: an evaporation device, a housing, a pump, and a controller. The evaporation device includes a sample fluid channel defined by the evaporation device and extending from a sample fluid inlet to a sample fluid outlet. The evaporation device is configured to evaporate a solvent of a sample fluid containing a target analyte such that the sample fluid exiting the sample fluid outlet has a higher concentration of the target analyte than that of the sample fluid entering the sample fluid inlet. The housing encloses and defines a testing environment within which the evaporation device is disposed. The housing includes a heater, a temperature sensor, and a humidity sensor each disposed within the testing environment. The pump is coupled to a gas inlet tube in fluid communication with the testing environment. The pump is configured to cause a gas flow within the testing environment adjacent to the evaporation device. The controller is in communication with each of the heater, the temperature sensor, and theAttorney Docket No.10046-586WO1 humidity sensor. The controller is configured to activate the heater in response to at least one of a temperature value or a humidity value of the testing environment.

[0005] In some implementations, at least a portion of the evaporation device is rinsible and reusable in additional preconcentration operations.

[0006] In some implementations, the evaporation device further includes a gas tube defining a gas channel extending from a gas inlet to a gas outlet, the gas channel coupled to and in fluid communication with the gas inlet tube. The evaporation device further includes a sample fluid tube defining the sample fluid channel, the sample fluid tube disposed within at least a portion of the gas channel with a radial gap defined between an inner surface of the gas tube and an outer surface of the sample fluid tube. The radial gap is configured for a gas to flow around and adjacent to the sample fluid tube. A length of the sample fluid tube defines a plurality of evaporation holes extending radially outward from an inner surface of the sample fluid tube to the outer surface of the sample fluid tube such that the sample fluid channel is in fluid communication with the gas channel.

[0007] In some implementations, the plurality of evaporation holes have a predefined density defined by a number of evaporation holes per area of an outer surface of the sample fluid tube (e.g., in the range of 0.1 / mm2 to 1 / nm2).

[0008] In some implementations, the solvent evaporates through the plurality of evaporation holes and into the gas channel, while the liquid phase of the sample fluid remains within the sample fluid channel.

[0009] In some implementations, the plurality of evaporation holes have a diameter in the range of 0.1 nanometer to 500 micrometers, inclusive.

[0010] In some implementations, the sample fluid tube and the gas channel are coaxial.

[0011] In some implementations, the evaporation device includes a plurality of sample fluid channels in fluid communication with the sample fluid inlet and the sample fluid outlet.

[0012] In some implementations, the sample fluid tube includes a first sample fluid tube and a second sample fluid tube each extending parallel to each other in at least a portion of the gas channel.

[0013] In some implementations, the sample fluid tube includes four separate sample fluid tubes each defining a portion of the sample fluid channel, wherein the four separate sampleAttorney Docket No.10046-586WO1 fluid tubes converge and combine adjacent to both the sample fluid inlet and the sample fluid outlet.

[0014] In some implementations, the evaporation device includes a plurality of sample fluid channels in fluid communication with the sample fluid inlet and the sample fluid outlet.

[0015] In some implementations, the evaporation device further includes a lower body defining the sample fluid channel and a gas permeable membrane disposed on an upper surface of the lower body. The evaporation device further includes a lid coupled to the lower body to retain the gas permeable membrane in place, the lid defining an evaporation opening aligned with the sample fluid channel of the lower body such that the solvent of the sample fluid evaporates through the gas permeable membrane, through the evaporation opening, and into the testing environment.

[0016] In some implementations, the controller is communication with the pump and configured to activate the pump to adjust a flowrate of the gas through the gas inlet tube.

[0017] In some implementations, the housing defines: (i) a first inlet for a sample fluid inlet tube in fluid communication with the sample fluid inlet of the evaporation device; (ii) a first outlet for a sample fluid outlet tube in fluid communication with the sample fluid outlet of the evaporation device; (iii) a second inlet for the gas inlet tube; and (iv) a second outlet for a gas outlet tube.

[0018] In some implementations, the preconcentration system further includes a collection container for the concentrated sample fluid exiting the housing coupled to the sample fluid outlet tube.

[0019] In some implementations, the preconcentration system further includes a user interface configured to display a value derived from the controller, wherein the value is any one of a temperature value, a humidity value, an airflow value, or an evaporation factor calculated by the controller.

[0020] In some implementations, the housing includes a transparent window configured to make visible the evaporation device from an exterior of the testing environment.

[0021] In some implementations, the target analyte is at least one of glucose, lactate, or pyruvate and the sample fluid is a brain fluid.

[0022] In some implementations, the target analyte is a DNA or RNA sample in a polymerase chain reaction (PCR) process.Attorney Docket No.10046-586WO1

[0023] In some implementations, the target analyte is a microdroplet.

[0024] In some implementations, the solvent of the sample fluid a non-aqueous liquid solution.

[0025] According to another implementation, a preconcentrator device is disclosed. The preconcentrator device includes a sample fluid tube and a gas tube. The sample fluid tube defines a sample fluid channel extending from a first end to a second end of the sample fluid tube. The sample fluid tube includes a plurality of evaporation holes extending radially from an inner surface of the sample fluid tube to an outer surface of the sample fluid tube. The device is configured to flow a sample fluid containing a target analyte and a solvent through the sample fluid channel from the first end to the second end. The gas tube defines a gas channel extending from a first end to a second end of the gas tube. The device is configured to flow a gas through the gas channel from the first end to the second end. The sample fluid tube is disposed within the gas channel of the gas tube, and the outer surface of the sample fluid tube is spaced apart from an inner surface of the gas tube. The device is configured to evaporate the solvent through the evaporation holes and into the gas channel to concentrate the target analyte of the sample fluid.

[0026] In some implementations, the gas and the sample fluid flow in opposing directions.

[0027] In some implementations, the first and second ends of the gas tube extend substantially perpendicularly with respect to the first and second ends of the sample fluid tube.

[0028] In some implementations, the preconcentrator device further includes a plurality of sample fluid tubes disposed within the gas channel.

[0029] In some implementations, each of the plurality of sample fluid tubes are in fluid communication with an inlet defined on the first end of the sample fluid tube and an outlet defined on the second end of the sample fluid tube.

[0030] In some implementations, the sample fluid tube includes a first sample fluid tube and a second sample fluid tube each extending parallel to each other in at least a portion of the gas channel.

[0031] In some implementations, the sample fluid tube includes four separate sample fluid tubes each defining a portion of the sample fluid channel, wherein the four separate sampleAttorney Docket No.10046-586WO1 fluid tubes converge and combine adjacent to both a sample fluid inlet on the first end and a sample fluid outlet on the second end.

[0032] According to another implementation, a method of concentrating an analyte is disclosed. The method includes providing an evaporation device including a sample fluid channel defined by the evaporation device and extending from a sample fluid inlet to a sample fluid outlet. A housing encloses and defines a testing environment within which the evaporation device is disposed. A pump is coupled to a gas inlet tube in fluid communication with the testing environment. The method further includes causing a sample fluid containing a target analyte and a solvent to flow through the sample fluid channel. The method further includes activating the pump to cause a gas to flow within the testing environment adjacent to the evaporation device having the sample fluid. The method further includes activating, via a controller, a heater within the housing to increase a temperature of the testing environment. The method further includes causing a controlled evaporation of the solvent from the sample fluid such that the sample fluid exiting the housing has a higher concentration of the target analyte than that of the sample fluid entering the housing.

[0033] In some implementations, the method further includes adjusting, via the controller, a flow rate of gas in the testing environment based on values received from a temperature sensor and a humidity sensor disposed within the testing environment.

[0034] In some implementations, the method further includes calculating an evaporation factor based on values received by the controller from a temperature sensor and a humidity sensor disposed within the testing environment, and a liquid and / or gas flow rate through the evaporation device, and displaying the evaporation factor on a user interface in communication with the evaporation device.

[0035] In some implementations, the method further includes collecting the concentrated sample fluid in a collection vial coupled to the sample fluid outlet of the evaporation device, and analyzing and / or performing tests on the concentrated sample fluid.

[0036] In some implementations, the method further includes removing the evaporation device from the testing environment at completion of a preconcentration operation, washing and / or sterilizing the evaporation device to remove residual sample fluid, and re-using the evaporation device in a second preconcentration operation.

[0037] In some implementations, the target analyte is at least one of glucose, lactate, or pyruvate and the sample fluid is a brain fluid.Attorney Docket No.10046-586WO1

[0038] In some implementations, the target analyte is a DNA or RNA sample in a polymerase chain reaction (PCR) process.

[0039] In some implementations, the target analyte is a microdroplet.

[0040] In some implementations, the solvent of the sample fluid a non-aqueous liquid solution.

[0041] Additional advantages will be set forth in part in the description which follows or may be learned by practice. The advantages will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive, as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG.1A shows a perspective view of a double-tube preconcentrator device, according to one implementation.

[0043] FIG.1B shows a perspective view of a cross section of the preconcentrator device of FIG.1A along line 1B-1B.

[0044] FIG.1C shows a section view from the bottom side of the preconcentrator device of FIG.1A along line 1C-1C.

[0045] FIG.1D shows a side view of the sample fluid tube of the preconcentrator device of FIG.1A.

[0046] FIG.1E shows a perspective view of the sample fluid tube of the preconcentrator device of FIG.1A.

[0047] FIG.1F shows an example prototype model of the preconcentrator device of FIG. 1A on a ruler for scale.

[0048] FIG.1G shows a perspective view of a double-tube preconcentrator device, according to another implementation.

[0049] FIG.1H shows a cross-sectional view of the preconcentrator device of FIG.1G.

[0050] FIG.1I shows a multi-tube preconcentrator device, according to one implementation.Attorney Docket No.10046-586WO1

[0051] FIG.1J shows a cross-sectional view of the multi-tube preconcentrator device taken along line J-J in FIG.1I.

[0052] FIGS.2A and 2B show cross-sectional diagrams of the double-tube preconcentrator device of FIG.1A with solvent and analytes modeled, according to one implementation.

[0053] FIG.3A shows a perspective view of the lower body of a preconcentrator device, according to one implementation.

[0054] FIG.3B shows a side view of a section of the preconcentrator device of FIG.3A.

[0055] FIG.3C shows a side view of a section of the preconcentrator device of FIG.3A, according to one implementation.

[0056] FIG.3D shows the device of FIG.3A with the lid and placed on a heater, according to one implementation.

[0057] FIG.3E shows a straight-channel implementation of the preconcentrator device of FIG.3A, according to one implementation.

[0058] FIG.4A shows a system diagram of a preconcentration system, according to one implementation.

[0059] FIG.4B shows a preconcentrator device in use with the system of FIG.4A.

[0060] FIG.4C shows the system of FIG.4A in a lab environment.

[0061] FIG.4D shows an example system implementing a preconcentrator device, according to another implementation.

[0062] FIG.4E shows an example system implementing a preconcentrator device, according to another implementation.

[0063] FIG.4F shows an example system implementing a preconcentrator device, according to another implementation.

[0064] FIG.4G shows an example system implementing a preconcentrator device, according to another implementation.

[0065] FIG.4H shows a portable preconcentrator system, according to one implementation.

[0066] FIG.5 shows a flowchart of the operation of a preconcentration system, according to one implementation.Attorney Docket No.10046-586WO1

[0067] FIG.6A shows an image of an example preconcentrator device next to a ruler, according to one implementation.

[0068] FIG.6B shows a microscope image of the pores of the device of FIG.6A.

[0069] FIG.7A shows a graph that illustrates the relative humidity and the corresponding minimum liquid feeding rate at different dry nitrogen gas flow rates at 30℃, according to an experimental implementation.

[0070] FIG.7B shows a graph that illustrates the minimum liquid flow rate for each dry nitrogen gas flow rate at 30℃, according to an experimental implementation.

[0071] FIG.7C shows a graph of evaporation ratio and concentration factor as a function of temperature for various liquid flow rates, with contact sweeping gas flow rate of 50 mL / min, according to an experimental implementation.

[0072] FIG.7D shows a graph of evaporation ratio and concentration factor for different sweeping gas flow rates, with constant temperature of 30℃ and liquid flow rate of 1.0 μL / min, according to an experimental implementation.

[0073] FIG.7E shows a graph of evaporation ratio versus liquid flow rate from 1 to 10 μL / min, according to an experimental implementation.

[0074] FIG.7F shows a graph of concentration factor versus liquid flow rate from 1 to 10 μL / min., according to an experimental implementation.

[0075] FIG.7G shows a graph of FTIR absorbance spectra of glucose at concentrations of 10, 20, and 40 mmol / L, together with those of two preconcentrated samples, according to an experimental implementation.

[0076] FIG.7H shows a calibration curve derived from peak heights at 1036 cm-1for known glucose concentrations, and for two preconcentrated samples, according to an experimental implementation.

[0077] FIGS.8A and 8B show graphs of the results of a static evaporation test for a flat preconcentrator device, without and with membrane, respectively, according to an experimental implementation.

[0078] FIG.8C shows a graph comparing the results of FIGS.8A and 8B.Attorney Docket No.10046-586WO1

[0079] FIG.9A shows a graph of evaporation ratio measured at relative humidities ranging from 0% to 80% with liquid flow rates between 1 and 10^μL / min, according to an experimental implementation.

[0080] FIG.9B shows a graph showing a linear relationship between evaporation ratio and humidity difference at a liquid flow rate of 5^μL / min, gas flow rate of 50^mL / min, and temperature of 30^°C, wherein the R² value is 0.96, according to an experimental implementation.

[0081] FIG.10A shows the molecular structure of PFBS along with the Fourier Transform Infrared (FTIR) Spectra of 5000 ppm of PFBS in water with 50 μm pathlength.

[0082] FIG.10B shows a graph of FTIR absorbance spectra of six calibration solutions with PFBS concentrations ranging from 5000 ppm to 100 ppm.

[0083] FIG.10C shows a Calibration curve constructed from the 1255 cm⁻¹ absorbance peak for PFBS solutions at different concentrations.

[0084] FIG.10D shows an absorbance graph with a comparison of an original sample (black) at 250 ppm and concentrated sample (red).

[0085] FIG.10E shows an absorbance graph with a comparison of an original sample (black) at 100 ppm and concentrated sample (red).

[0086] FIG.11A shows a graph of FTIR absorbance spectra and calibration curve of 10 mM glucose solutions concentrated at 30°C, 1 μL / min sample flow, and 20 mL / min air flow (9.3%, 9.4%, 9.4% RH).

[0087] FIG.11B shows a graph of FTIR absorbance spectra and calibration curve of 10 mM lactate solutions concentrated at 30°C, 1 μL / min sample flow, and 20 mL / min air flow (9.3%, 9.4%, 9.4% RH).

[0088] FIG.11C shows a graph of FTIR absorbance spectra and calibration curve of 10 mM pyruvate solutions concentrated at 30°C, 1 μL / min sample flow, and 20 mL / min air flow (9.3%, 9.4%, 9.4% RH).

[0089] FIG.11D shows a graph of the calibration curve for lactate based on the peak at 1041 cm⁻¹.

[0090] Various objects, aspects, features, and advantages of the disclosure will become more apparent and better understood by referring to the detailed description taken inAttorney Docket No.10046-586WO1 conjunction with the accompanying drawings, in which like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and / or structurally similar elements. DETAILED DESCRIPTION

[0091] Referring generally to the figures, concentration devices and systems are shown, according to various implementations. The devices, systems, and methods herein described provide for an efficient, portable, continuous, and / or point-of-care solutions for increasing the concentration of an analyte or other target compound, molecule, or detectable particle. The disclosed devices, systems, and methods increase the concentration of a non-volatile analyte (e.g., a biomolecule, a non-biological molecule, a compound, a chemical organic, or a non- organic contaminant) in a solvent (e.g. water) to facilitate measurement and / or detection of the analyte using analytical instruments.

[0092] In analytical chemistry and biochemical processing, concentrating analytes (or other target particles) can improve detection or measurement sensitivity and make sample preparation easier. Preconcentration is essential under certain circumstances to enhance the detectability and accuracy of analytical measurements, especially when dealing with samples that contain very low concentrations of the target analyte. An evaporator concentrator is a device designed to enhance the concentration of analytes in a liquid via solvent evaporation process, which involves removing the solvent, typically water, thereby increasing the concentration of the less volatile analytes. Such ability proves particularly valuable in applications that require high sensitivity in chemical analysis, as concentrating the analyte significantly improves detection limits. Outputs from evaporator concentrators can be effectively integrated with sophisticated detection systems like surface-enhanced Raman spectroscopy (SERS) and infrared spectroscopy (IR), to enhance analytical performance.

[0093] Increasing sample concentration is also important because accurate measurements and signal-to-noise ratio depend on the concentration of the analyte. The higher the concentration, the easier it is to measure with high confidence / accuracy. Normally, measurement of very low concentrations is especially challenging, unless very expensive and specialized instruments are used. However, the devices, systems, and methods herein described provide a solution for portable, point-of-care, and continuous measurement via pre- concentration of the analyte samples. The disclosed devices, systems, and methods increaseAttorney Docket No.10046-586WO1 the concentration of analytes in the liquid sample prior to performing the measurement to either detect the presence of the molecule or to quantitively measure its concentration.

[0094] In this disclosure, an analyte of interest may include, but is not limited to, a non- volatile analyte, a biomolecule, a non-biological molecule, a compound, a chemical organic, a non-organic contaminant, or any other detectable particle. In some implementations, the target analyte is a molecule such as glucose, lactate, dopamine, enzymes, proteins, misfolded proteins, or vesicles. In other implementations, an analyte of interest can be a non-biological analyte, including but not limited to microplastics or toxic pollutants in water. In other implementations, the analyte of interest may be a DNA (or RNA) sample in a polymerase chain reaction (PCR) process. For example, the PCR process may involve various reagents and multiple cycles to amplify a DNA segment, which may depend on the original concentration of the DNA sample in the solvent. The disclosed preconcentrator device and system may be used to concentrate the DNA sample in place or, or optionally in conjunction with, traditional use of ethanol precipitation or DNA concentration protocol. The preconcentrator device and system of the present disclosure improves on the overall time involved, quality of the sample (e.g., amount of contaminants), and concentration of the sample as compared to the DNA concentration protocol.

[0095] The disclosed preconcentrator device and system may have additional or alternative applications in environmental analysis. For example, the disclosed preconcentrator systems and devices are capable of detecting pollutants in low concentrations in air or water. Such environmental applications are useful in water and / or air quality testing, such as measuring environmental pollutants in runoffs (e.g., runoff water from a facility). More broadly, the disclosed preconcentrator devices and systems may be used for contaminant testing in consumables, such as in food, beverage, or pharmaceutical applications. The advantages of the preconcentration methods disclosed herein, and the associated devices and systems, are not limited to the examples described herein, and additional applications and uses for the disclosed devices and systems are contemplated by this disclosure.

[0096] In some implementations, the disclosed preconcentrator systems and devices may be used with microdroplets, which are usually made by mixing aqueous and oil-based solvents. Microdroplets in microfluidics can be used as micro-reactors, for single cell studies, and in many more applications.Attorney Docket No.10046-586WO1

[0097] In some implementations, the fluid used in the disclosed preconcentrator systems and devices may include a non-aqueous liquid solution. In such cases, an organic solvent molecule may evaporate from the solution, and a volatile organic compound sensor may be used in the system in place of the humidity sensor.

[0098] In some implementations, the operating principle of exemplary systems and devices is based on controlled evaporation of solvent (e.g. water), thus increasing the concentration of non-volatile biomolecules in the resulting sample. Evaporation is induced and controlled by the temperature of the sample and by convection of air. For effective / rapid evaporation, raising the temperature can facilitate evaporation. Additionally, controlling the air flow around the evaporation area can facilitate evaporation via convection.

[0099] As will be further described, implementations of this disclosure may include a device for evaporating the solvent that is situated within a box or housing. The housing serves to define an experimental environment wherein controlled evaporation occurs. The housing can protect from environmental changes, maintain temperature inside the housing (e.g., with a heater), provide for temperature control of a flowing sample liquid, provide for temperature control of flowing air within the housing (e.g., via a pump for constant airflow), measure the temperature and humidity (e.g., via sensors within the housing), and house controls and electronics associated with the environmental control. Examples of this housing will be further described herein with reference to the figures.

[0100] Specific applications of this system may include continuous measurement of glucose, lactate, and pyruvate of traumatic brain injury patients, which is important for clinical management. Currently, a micro-dialysis technique is used to collect brain fluid sample (e.g., cerebral spinal fluid (CSF)) from the patients’ brain every hour. The sample is then taken to an analyzer. Pyruvate’s concentration is 10 times lower than glucose and lactate, so even the best current infrared systems struggle to achieve the desired detection limit for pyruvate. The current process is labor intensive and prohibits such monitoring in many trauma / ICU hospitals.

[0101] Preconcentrator devices and systems disclosed herein can be upstream of an infrared analyzer thereby concentrating sample fluid before analysis in the infrared analyzer enabling the measurement of pyruvate. Therefore, the proposed technology has at least one application for traumatic brain injury monitoring. Double-Tube Preconcentrator DeviceAttorney Docket No.10046-586WO1

[0102] In one implementation, a preconcentrator device is disclosed for flowing a sample fluid therethrough and facilitating evaporation of a solvent. The exemplary preconcentrator device is configured to be placed and used within a housing of this disclosure for monitoring, sensing, and environmental control.

[0103] The disclosed preconcentrator device may be manufactured via 3D printing (e.g., micro-3D printing). Micro 3D printing allows for precise and customized fabrication of tiny microfluidic chips. High-resolution printing techniques, including liquid-crystal display (LCD) 3D printing, have achieved resolutions as low as 18-50 µm, making it possible to create detailed microfluidic channels and structures needed for applications like organ-on- chip devices and biological tests. Micro 3D printing facilitates rapid design iteration and prototyping, enabling researchers to swiftly test and refine their designs, which is essential for developing complex microfluidic systems for diverse applications. The example preconcentrator device of FIGS.1A-1H may be fabricated via micro-3D printing using biocompatible materials.

[0104] FIGS.1A-1F show a preconcentrator device 100, according to one implementation. In some implementations, the preconcentrator device 100 is a monolithic 3D printed double tube design. In some implementations, the preconcentrator device 100 is produced via injection molding. In some implementations, the preconcentrator device 100 is formed from a polymer. In some implementations, at least a portion of the preconcentrator device may be rinsible and reusable in additional preconcentration operations.

[0105] The preconcentrator device 100 defines a first end 102 and a second end 104 opposite and spaced apart from the first end 102 along a longitudinal axis 101. The first end 102 may be an “inlet end” and the second end 104 may be an “outlet end”. The preconcentrator device 100 includes a sample fluid tube 110 and a gas tube 130, each extending from the first end 102 towards the second end 104 of the preconcentrator device 100 in the direction of the longitudinal axis 101 (a “longitudinal direction” of the preconcentrator device 100). The longitudinal axis 101 of the preconcentrator device 100 extends through the sample fluid tube 110. In some implementations, the sample fluid tube 110 is coaxial with the gas tube 130.

[0106] The sample fluid tube 110 of the preconcentrator device 100 defines a sample fluid channel 112 extending from the first end 102 to the second end 104 of the sample fluid tube 110 and the preconcentrator device 100. Specifically, the sample fluid tube 110 includes anAttorney Docket No.10046-586WO1 inner surface 120 and an outer surface 122 spaced apart from each other to define a thickness of the sample fluid tube 110. The inner surface 120 defines the sample fluid channel 112.

[0107] The sample fluid tube 110 defines a fluid inlet 114 on the first end 102 and a fluid outlet 116 on the second end 104. Each of the fluid inlet 114 and the fluid outlet 116 are in fluid communication with the sample fluid channel 112. Each of the fluid inlet 114 and the fluid outlet 116 are couplable to a fluid source / drain (e.g., an acrylic tube) such that the preconcentrator device 100 is configured for a flow of a sample fluid containing a target analyte and a solvent through the sample fluid channel 112 from the first end 102 to the second end 104 of the preconcentrator device 100.

[0108] The sample fluid tube 110 further defines a plurality of evaporation holes 118 (e.g., micro-holes or micro-pores). The evaporation holes 118 extend radially (e.g., away from and or perpendicular to the longitudinal axis 101) from the inner surface 120 of the sample fluid tube 110 to the outer surface 122 of the sample fluid tube 110. As shown, the plurality of evaporation holes 118 are 50 μm in diameter and spaced apart by 250 μm. However, in other implementations, the size and spacing of the evaporation holes is modified based on the surface tension of the solvent, the desired evaporation rate or factor, and other specific parameters of the system. Throughout this disclosure, all dimensions recited herein or shown in the figures are exemplary only and are not meant to limit the scope of the disclosure.

[0109] The gas tube 130 of the preconcentrator device 100 includes an inner surface 132 and an outer surface 134 spaced apart from the inner surface 132 to define a thickness of the gas tube 130. The inner surface 132 of the gas tube 130 defines a gas channel 136 extending from the first end 102 to the second end 104 of the gas tube 130 and the preconcentrator device 100. The preconcentrator device 100 is configured to flow a gas (e.g., air having a controlled temperature and humidity) through the gas channel 136 from the first end 102 to the second end 104.

[0110] The gas tube 130 defines a gas inlet 138 on the first end 102 and a gas outlet 140 on the second end 104 of the preconcentrator device 100. Each of the gas inlet 138 and the gas outlet 140 are in fluid communication with the gas channel 136. Each of the gas inlet 138 and the gas outlet 140 are couplable to a gas source / drain (e.g., an acrylic tube) such that the preconcentrator device 100 is configured flow a gas through the gas channel 136 from the first end 102 to the second end 104 of the preconcentrator device 100. The gas may flowAttorney Docket No.10046-586WO1 through the gas channel 136 in the same flow direction as the sample fluid in the sample fluid tube 110 or in the opposite direction (e.g., counter flow).

[0111] As shown, the gas tube 130 is coaxial with the sample fluid tube 110 about the longitudinal axis 101 for at least a portion of the preconcentrator device 100 between the first end 102 and the second end 104. The gas tube 130 has a diameter larger than the sample fluid tube 110 in that portion such that the inner surface 132 of the gas tube 130 is spaced apart from the outer surface 122 of the sample fluid tube 110. Thus, the gas channel 136 is further defined on a radially inward side by the outer surface 122 of the sample fluid tube 110 such that the gas channel 136 is annular about the longitudinal axis 101.

[0112] Notably, the gas tube 130 turns to extend radially away from the sample fluid tube 110 on either end of the preconcentrator device 100. For example, the gas tube 130 on each of the first end 102 and the second end 104 turns 90 degrees to extend away from the longitudinal axis 101. Thus, the sample fluid tube 110 and the sample fluid channel 112 extend through the sidewall of the gas tube 130. A discontinuity in the flow path of the gas channel 136 is created by the extending of the sample fluid tube 110 through the gas tube 130 sidewall. However, the flow of gas through the gas channel 136 is not substantially hindered.

[0113] The sample fluid channel 112 is in fluid communication with the gas channel 136 via the plurality of evaporation holes 118. These plurality of evaporation holes 118 (e.g., micro-sized holes) are used for vapor evaporation in a radial direction from the sample fluid channel 112 to the gas channel 136. The plurality of evaporation holes 118 are small enough so that liquid from the sample fluid in the sample fluid channel 112 does not leak out (e.g., between 0.1 nanometers and 500 micrometers in diameter, such as 50 micrometers in diameter). The vapor phase of the evaporated sample fluid can move through the plurality of evaporation holes 118 into the gas channel 136. Thus, the preconcentrator device 100 is configured to evaporate the solvent of the sample fluid flowing through the sample fluid channel 112 to concentrate a target analyte of the sample fluid. Airflow through the gas channel 136 facilitates this evaporation process.

[0114] The preconcentrator device 100 of FIGS.1A-1F includes the following dimensions; however, it will be understood that other implementations of the device may have different dimensions or ratios of dimensions as required for a specific use-case.

[0115] The fluid inlet 114 and the fluid outlet 116 of the sample fluid tube 110 have an outer diameter of 1.2 mm and an inner diameter of 0.72 mm (e.g., fit for a 22 gage tubeAttorney Docket No.10046-586WO1 having, for example, an outer diameter of 0.718mm and an inner diameter of 0.413 mm). However, in other implementations, the sample fluid tube may be sized between 0.1 mm and 50 mm.

[0116] The gas inlet 138 and the gas outlet 140 of the gas tube 130 have an outer diameter of 2.9 mm and an inner diameter of 1.9 mm (e.g., fit for a 1 / 16 inch tube). However, in other implementations, the gas tube may be sized between 0.1 mm and 500 mm as an outer diameter.

[0117] The plurality of evaporation holes 118 span a portion of the sample fluid tube 110 that is 10mm in length, as shown in FIG.1C. This length where the holes are located may be defined as the “effective length” of the device 100. The effective length shown in FIG.1C is 10 mm; however, in other implementations, the effective length may be in the range of 0.5 mm to 500 mm. The diameter of the plurality of evaporation holes 118 is 50 μm. However, in other implementations, the evaporation holes may have a diameter in the range of 1 nm to 2 mm (e.g., 30 or 70 μm). The plurality of evaporation holes 118 are spaced apart from each other by 250 μm. However, in other implementations, the evaporation holes are spaced apart from each other by a distance in the range of 1nm to 500 mm.

[0118] While the effective length contributes to the overall calculation and definition of the evaporation rate of the device 100, an effective area of the outer surface of the sample fluid tube 110 may also be used. Using the dimensions of various elements of the preconcentrator device 100, an “interface area” or “contact area” may be calculated. The interface area or total contact area is defined as the total area of evaporation across the fluid inlet tube. In oneexample, the total contact area is provided by the following equation:^^ = ^^^^ ∗ ^^^^ (1)where A is the total contacta single pore (a single evaporation hole or micro-hole), and Nmpis the total number of pores or holes in the effective area.

[0119] In the preconcentrator device 100, the radius of an evaporation hole is 25 μm or 25x10-6m. Additionally, the 10 mm section of effective length includes 632 total holes. Thus, A = [π*(25x10-6) * 632] = 1.241 mm2. However, in other implementations, the preconcentrator device, and the sample fluid tube thereof, may have total contact area in the range of 0.1 mm2to 1000 cm2.Attorney Docket No.10046-586WO1

[0120] FIGS.1G and 1H show another preconcentrator device 100’ that is substantially similar to the preconcentrator device 100 of FIGS.1A-1F. FIG.1G shows the device 100’ with a fluid inlet 114 for a liquid sample, a fluid outlet 116 for a liquid sample, a gas inlet 138, and a corresponding gas outlet 140 for the humidified gas. FIG.1H displays a cross- section of the computed-aided design (CAD) model of the device 100’ demonstrating the principle of evaporation in a plurality of directions.

[0121] The interface surface area (where liquid is exposed to the gas) is calculated by summing up the areas of all the pores / holes. The extent of the liquid-gas interface area significantly influences the efficiency of the evaporation process. In the device 100’, the sweeping gas entirely surrounds the liquid channel, maximizing the contact area for evaporation via forced convection.

[0122] The size of the evaporation holes or pores may be controlled to ensure that they are neither too large, which would cause liquid leakage, nor too small, which would reduce the liquid-gas interface area below what is needed for effective evaporation. The diameter of the evaporation holes or pores, represented by the letter Φ, directly influences the liquid sample feeding rate or flow pressure. Specifically, the evaporation hole or pore cylinder acts as a barrier to the liquid phase as long as the liquid pressure stays below the capillary penetration pressure. This means that if the liquid pressure exceeds the capillary penetration pressure, the liquid will penetrate through the pores. Smaller pores create a higher capillary pressure barrier, preventing the liquid from passing through unless there is sufficient pressure. As a result, a higher feeding rate generates increased flow pressure, which in turn necessitates the use of smaller pores to maintain control over the liquid flow. Conversely, larger pores would allow the liquid to pass through more easily, reducing the control over the feeding rate and flow pressure. Therefore, precise control over the pore size is implemented for managing the liquid sample feeding rate and flow pressure effectively. For example, for some implementations, a pore diameter of 100 μm is sufficient for a liquid flow rate of less than 12 μL / min, (e.g., 10 μL / min).

[0123] The length of the segment housing the evaporation holes or pores is termed here as 'effective length', represented by the letter s in FIG.1G. The pore diameter, the distance between adjacent pores (represented by the letter d), and the effective length collectively determine the total interface area. These dimensions are primarily determined by the manufacturing process. The pore diameter and the distance between adjacent pores are dictated by the resolution of the micro 3D printer. The effective length, the total lengthAttorney Docket No.10046-586WO1 (represented by the letter L), and the thickness of the liquid tube (represented by the letter m), are constrained by the limitations of the printer to avoid issues such as shrinkage and bending. In the device 100’, with reference to the dimensional lettering in FIGS.1G and 1H, the diameter of the evaporation holes or pores (Φ) = 50 μm. The distance between adjacent holes / pores (d) = 250 μm. The effective length (s) = 10 mm. The total length (L) = 16 mm. The thickness of the liquid tube (m) = 300 μm. As described above, the effective length may also contribute to the effective area or “contact area” of the device.

[0124] The device 100’ is a single part that does not require assembly and can function directly after 3D printing. Being a concentric-shaped cylinder with intricate structures on the inner tube, micro-3D printing surpasses traditional mechanical manufacturing methods.

[0125] The device 100 and the device 100’ are shown having a substantially linear orientation with the sample fluid tube having a cylindrical shape. However, other implementations of the disclosed concentric tube device are not limited to a linear design. For example, other devices may have a curvature along the longitudinal axis. In some examples, overall shape of the device (e.g., the shape of the sample fluid tube and the portion of the gas tube surrounding the sample fluid tube) may be serpentine, semi-circular, spiral, or other shapes that provide for additional fluid flow time from one end of the device to the other. Multi-Tube Preconcentrator Device

[0126] The device 100 of FIGS.1A-1F includes a single sample fluid tube 110 extending through the surrounding gas tube 130. However, in other implementations of the present disclosure, additional sample fluid tubes extend through the gas tube adjacent to each other (e.g., parallel to each other). For example, other implementations of the preconcentrator device include 2, 3, 4, 5, 6, 7, 8, 9, 10 or more sample fluid tubes extending at least partially through the channel defined by the surrounding gas tube. The additional sample fluid tubes allow for additional solvent evaporation capacity, concentrating the sample faster than a single sample tube. In other implementations, the additional sample fluid tubes allow for multiple samples to be preconcentrator at once (e.g., via discrete fluid sample tubing). The parallel structure, where multiple liquid tubes operate simultaneously, increases the total evaporation capacity without compromising the interfacial area or pressure requirements of each individual tube, effectively achieving higher throughput without sacrificing efficiency.

[0127] FIGS.1I and 1J show a preconcentrator device 150, which is substantially similar to the structure and function of the preconcentrator device 100, except as described below. TheAttorney Docket No.10046-586WO1 preconcentrator device 150 includes gas tube 160 having an inner surface 162 and an outer surface 164. The inner surface 162 defines a gas channel 166 extending from a first end to a send end of the preconcentrator device 150 (e.g., along a longitudinal axis thereof). The preconcentrator device 150 is configured to flow a gas (e.g., air having a controlled temperature and humidity) through the gas channel 166 from the first end to the second end. The gas tube 160 further defines a gas inlet 168 and a gas outlet 169 on opposite ends of the preconcentrator device 150. Each of the gas inlet 168 and the gas outlet 169 are in fluid communication with the gas channel 166. Each of the gas inlet 168 and the gas outlet 169 are couplable to a gas source / drain (e.g., an acrylic tube insertable into, or configured to encapsulate, the respective inlet or outlet). The gas tube 160 has an inner diameter of 6.12 mm and an outer diameter of 7.5 mm. However, these dimensions are exemplary only, and other sizing is contemplated by this disclosure.

[0128] The preconcentrator device 150 further includes a sample fluid tube 170, similar to the sample fluid tube 110 of the preconcentrator device 100. However, the sample fluid tube 170 in the preconcentrator device 150 splits into four separate tubes within the gas channel 166. As shown in FIG.1I, the sample fluid tube 170 includes an inlet portion 172 defining an inlet channel 173 on the first end of the preconcentrator device 150. The sample fluid tube 170 further includes an outlet portion 174 defining an outlet channel 175 on the second end of the preconcentrator device 150. Each of the inlet portion 172 and the outlet portion 174 of the sample fluid tube 170 are couplable to a fluid source / drain (e.g., an acrylic tube) such that the preconcentrator device 150 is configured for a flow of a sample fluid containing a target analyte and a solvent through the sample fluid tube 170 from the first end to the second end.

[0129] The inlet channel 173 is in fluid communication with the outlet channel 175 of the sample fluid tube 170 via one or more lumens, channels, or tubes extending therebetween. As shown, the preconcentrator device 150 includes four evaporation tubes extending through the gas channel 166. The evaporation tubes are shown as evaporation tubes 180a, 180b, 180c, and 180d. Each of the evaporation tubes 180a-180d are substantially similar to the other such that reference is made only to the first evaporation tube 180a with the understanding that the description is equally applicable to the other evaporation tubes 180b-180d. Each of the evaporation tubes 180a-180d extend along their own longitudinal axis through the gas channel 166 and are arranged in a substantially circular pattern relative to each other (e.g., a circle with a diameter of 4^mm). However, in other implementations, the evaporation tubes may extend at an angle relative to each other and / or a different pattern than shown. In otherAttorney Docket No.10046-586WO1 implementations, the evaporation tubes may extend through the gas channel in an extended length pattern, such as a curved shape, a helix shape, or another shape increasing the overall effective length and / or area of the evaporation tube.

[0130] The first evaporation tube 180a includes an inner surface 182 and an outer surface 184 radially spaced apart from the inner surface 182 to define a thickness of the first evaporation tube 180a. The inner surface 182 of the first evaporation tube 180a defines a first evaporation channel 186. The first evaporation tube 180a further defines a plurality of evaporation holes 188 (e.g., micro-holes or micro-pores, similar to the plurality of evaporation holes 118 of the preconcentrator device 100). The evaporation holes 188 extend radially from the inner surface 182 to the outer surface 184 of the first evaporation tube 180a. As shown, the plurality of evaporation holes 188 are 30 μm in diameter and spaced apart by 150 μm. The overall length of the first evaporation tube 180a is 15mm. However, in other implementations, the size and spacing of the evaporation holes is modified based on the surface tension of the solvent, the desired evaporation rate or factor, and other specific parameters of the system. Throughout this disclosure, all dimensions recited herein or shown in the figures are exemplary only and are not meant to limit the scope of the disclosure.

[0131] The first evaporation channel 186 is in fluid communication with the gas channel 166 via the plurality of evaporation holes 188. These plurality of evaporation holes 188 are used for vapor evaporation in a radial direction from the first evaporation channel 186 to the gas channel 166. The plurality of evaporation holes 188 are small enough so that liquid from the sample fluid in the first evaporation channel 186 does not leak out (e.g., between 0.1 nanometers and 500 micrometers in diameter, such as 50 micrometers in diameter). The vapor phase of the evaporated sample fluid can move through the plurality of evaporation holes 188 into the gas channel 166. Thus, the preconcentrator device 150 is configured to evaporate the solvent of the sample fluid flowing through the first evaporation channel 186 to concentrate a target analyze of the sample fluid. Airflow through the gas channel 166 facilitates this evaporation process.

[0132] The first evaporation channel 186 of the first evaporation tube 180a is in fluid communication with the inlet channel 173 via a connector tube 190. The first evaporation channel 186 of the first evaporation tube 180a is in fluid communication with the outlet channel 175 via a connector tube 192. Each of the other evaporation tubes 180b-180d, and the channels defined thereby, are in fluid communication with each of the inlet channel 173 and the outlet channel 175 via similar connector tubes. The connector tubes 190, 192, areAttorney Docket No.10046-586WO1 angled relative to the inlet portion 172, the outlet portion 174, the first evaporation tube 180a, and / or their respective longitudinal axes. As shown, the connector tubes 190, 192 do not include evaporation holes. However, in other implementations, the connector tubes may include evaporation holes.

[0133] The four connector tubes of each of the evaporation tubes 180a-180d converge at each of the inlet portion 172 and the outlet portion 174, forming a continuous structure with a common input and output. Providing four evaporation channels – rather than the single sample fluid tube 110 of the preconcentrator device 100 – increases the evaporation capacity of the preconcentrator device 150 (e.g., by 4 times). Thus, the preconcentrator device 150 may concentrate the sample and / or evaporate the solvent faster than implementations with fewer evaporation tubes carrying a sample fluid.

[0134] In preconcentrator device 150 and similar designs, the area of the inner diameter of the main liquid inlet / outlet tubing (e.g., the inlet channel 173 and the outlet channel 175) is matched to be equal to the sum of each of the four internal tubes (e.g., the first evaporation channel 186). This uniformity minimizes flow resistance and prevents sudden pressure changes or turbulence at the junctions. It ensures uniform flow distribution among the four channels, enhancing the stability and reproducibility of the preconcentration process. Moreover, the seamless transition between the external and internal flow paths simplifies connection and reduces the risk of clogging or backflow. Theoretical Analysis

[0135] The manipulation of evaporation rates contributes to the overall operation of evaporator concentrators, aiming to concentrate solutes in aqueous solutions. Evaporation rates are influenced by factors such as the diffusion coefficient of water vapor, liquid-gas interface area, and the vapor pressure gradient between the liquid surface and the surrounding gas.

[0136] The channel prevents liquid passage while permitting vapor diffusion through the pores. The enriching particles may be either aqueous-soluble or aqueous-insoluble, as long as their loss is controllable. The water mass balance in the evaporator is represented by Equation2.^^ప^^ = ^^^^௨௧ + ^^^^௩^ (2)Attorney Docket No.10046-586WO1where ^^ప^^ and ^^^^௨௧ denote the rates of sample solution feeding and collection, respectively,and ^^^^௩^ represents the solvent evaporation rate.

[0137] FIGS.2A and 2B show a diagram representing a longitudinal cross section of the double-tube preconcentrator device 100 of FIGS.1A-1F. The diagrams of FIGS.2A and 2B show a section of the effective area of the preconcentrator device 100 having the sample fluid tube 110 and the gas tube 130 (which may be the same as the first evaporation tube 180a of the preconcentrator device 150). FIGS.2A and 2B show more details on the evaporative process of solvent via the evaporation holes in the sample fluid tube.

[0138] FIG.2A shows a sample solution flowing through the sample fluid channel 112 of the sample fluid tube 110 in a first direction along the longitudinal axis 101. The flow rate of the sample solution is represented by Uliquid. A gas flows through the gas channel 136 of the gas tube 130 in a direction opposite of the first direction along the longitudinal axis 101. The flow rate of the gas is represented by Ugas. The flow rate for the liquid may be in the range of 0.1 μL / min to 100 mL / min. The flow rate for the gas may be in the range of 0.1 – 1000 standard cubic centimeters per minute (SCCM).

[0139] FIG.2B shows small circles, representing the volatile solvent (e.g., water) vapor, and large circles, representing the non-volatile (bio)molecules (e.g., glucose, proteins, or microparticles). As shown, the volatile solvent (small circles) evaporate through the plurality of evaporation holes 118 into the gas channel 136. However, the non-volatile (bio)molecules do not evaporate and remain within the sample solution. As a result of the evaporating solvent, the sample solution becomes more concentrated with the target analyte (e.g., the non- volatile (bio)molecules).

[0140] FIG.2B also shows a schematic cross-section of a single evaporation hole (e.g., a micro-hole or pore). The surface area increases due to the meniscus, compared to a flatliquid-gas interface, and the meniscus evaporation is governed by the Kelvin equation:^^^^ ^ಾ = ସఊ^^ୡ୭^ (ఏ)^ಷ ^ோ் (3)where ^^ெis the equilibrium vapor pressure over the meniscus curved surface, ^^ிis the equilibrium vapor pressure over a flat surface of the same liquid, ^^ is the surface tension ofthe liquid (in this case, 0.11 ∗ 10ିଷ^^ / ^^), ^^^ is the molar volume of the liquid (pure water^^^ = 18 ^^^^ଷ / ^^^^^^), ^^ is the contact angle, approximately 50 degrees between water and theAttorney Docket No.10046-586WO1 material, Φ is the diameter of the pore, ^^ is the ideal gas constant, and ^^ is the temperature inKelvin. It has been calculated that ^^ெ = 1.04^^ி.

[0141] A simplified version of the meniscus evaporation rate ^^ெ^ equation can be related tothe diffusion coefficient ^^, the total area of the evaporation holes or pores ^^, and the watervapor pressure difference, as defined in Equation 4.^^ெ^ = ^^^^(^^ெ − ^^^^^) (4)

[0142] An engineering method employing a relative humidity sensor is used to estimate total evaporation over time. By monitoring the relative humidity level at the outlet of the evaporator, the total evaporation can be estimated. In other implementations, a volatile organic compound (VOC) sensor may be used in place of the humidity sensor. As shown in FIG.2B, the evaporation mass rate at the holes / pores is the same as the water vapor mass flow rate at the outlet of the sweeping gas due to the water vapor mass balance. Therefore, the study must first calibrate the water vapor mass flow rate using different sweeping gas flow rates, then calculate the evaporation ratio.

[0143] From the calibration curve, the theoretical evaporation ratio (ER) can be calculatedfrom relative humidity using Equation 5.^^^^ = ^^ ^^ெೈೇ ^ೈೇ,ೄಲ^ ^ೄ^ಸெೄಸ ^ೄಸ ^^^ೄ (5)where C is a constant empiricaloutlet of the sweeping gas, ^^^^and ^^ௌீare the molar masses of water vapor and sweeping gas, respectively, ^^^^,ௌ^்and ^^ௌீare the saturation pressures of water vapor at specifictemperatures and pressures of the sweeping gas, ^^ௌ^ீ and ^^^^ௌ are the mass flow rates ofsweeping gas and liquid solution, calculated from volumetric flow rates and their respective densities. The concentration factor can be calculated from the evaporation ratio using Equation 6, assuming the solution's density does not vary significantly before and after theevaporation process.^^^^ = ி^^^^ ^^^^^^௧^^௧^^^ ^ூ^^௧^^^ ^^^^^^௧^^௧^^^ = ^ିாோ (6)

[0144] There are several advantages of this additive manufactured evaporator concentrator. First, the setup is easy to design and fabricate. Traditional microfluidics fabrication methods typically require complex multilayer CAD designs and diverse manufacturing processes. Using micro-3D printing technology, researchers can easily design and print 3D microfluidicAttorney Docket No.10046-586WO1 channels like standard 3D printed parts. Second, the fabrication's perfect repeatability allows for easy adjustment of the evaporator’s dimensions, particularly the sizes and shapes of the evaporation holes (e.g., micro-pores). The additive manufacturing process ensures that the printed evaporation hole / pore diameters fall within an acceptable range. Additionally, with known evaporation hole / pore dimensions and channel materials, researchers can more easily and accurately model and simulate the evaporation process mathematically. The evaporator concentrator is designed to operate at low temperatures (<40℃) to prevent the degradation of sensitive analytes, especially biomolecules. This low-temperature operation ensures that the structural integrity and functionality of proteins, nucleic acids, and other delicate biomolecules are preserved during the concentration process. This feature makes the device particularly suitable for concentrating biological samples where maintaining the activity and stability of the analytes is essential. Microfluidic Channel Device

[0145] In another implementation, a preconcentrator device is disclosed for flowing a sample fluid therethrough and facilitating evaporation of the solvent. The exemplary preconcentrator device is configured to be contained and utilized within a housing of this disclosure for monitoring, sensing, environmental control.

[0146] FIGS.3A-3E show a preconcentrator device 200 which may be understood as a “flat” implementation or a “microfluidic channel” implementation. The preconcentrator device 200 includes a lower body 202 defining a sample fluid channel 204. The sample fluid channel 204 is configured to flow a sample fluid therethrough from a fluid inlet 206 to a fluid outlet 208. The pathway of the sample fluid channel 204 may be linear (as in the implementation of FIG.3E), circular (as in the implementation of FIG.3A), or any other shape (e.g., serpentine). The lower body 202 may be manufactured via 3D printing or silicone manufacturing. In some implementations, the preconcentrator device may be rinsed, sterilized, and reused for another operation.

[0147] The preconcentrator device 200 further includes a gas permeable membrane 212. The gas permeable membrane 212 is disposed on an upper surface 210 of the lower body 202. The gas permeable membrane 212 is retained on the preconcentrator device 200 by a lid 214 coupled to the lower body 202. The lid 214 includes openings for fasteners that engage with corresponding openings 218 in the lower body 202. For example, four screws may holdAttorney Docket No.10046-586WO1 the lid 214 onto the lower body 202, the screws extending through each of the openings. The lid 214 is held tightly to the lower body 202 such that sample liquid cannot leak out.

[0148] The gas permeable membrane 212 may be a porous membrane, including a polymer, with small pores sized to allow vapor (e.g., water vapor) to evaporate through, but small enough to keep liquid solvent (e.g., liquid water) and target analytes held within the sample liquid in the lower body 202. In some implementations, the gas permeable membrane may include more than one membrane. The type, material, size, and overall dimensions of the gas permeable membrane may be adjusted based on the fluid mechanics of the system, the target analyte being investigated, and other use-specific scenarios.

[0149] The lid 214 defines an evaporation opening 216. The evaporation opening is aligned with the sample fluid channel 204 of the lower body 202. For example, FIG.3B shows a section of the preconcentrator device 200 where the evaporation opening 216 is shown over the sample fluid channel 204 (i.e., the lid adjacent to the evaporation opening is not visible). The evaporation opening 216 tracks the geometry of the sample fluid channel 204 below (e.g., straight, circular, or serpentine).

[0150] Similar to the double-tube preconcentrator elsewhere described, the evaporation of the solvent from the sample fluid channel 204 of the preconcentrator device 200 is driven by a combination of heat and forced air. Thus, the evaporation opening 216 allows for the solvent (e.g., water) of the sample fluid to evaporate through the gas permeable membrane 212 and into the testing environment surrounding the preconcentrator device 200. System Design and Implementation

[0151] This disclosure contemplates that the above-described preconcentration devices may be used with an associated preconcentration system. For example, FIG.4A shows diagram of a preconcentration system, according to various implementations. FIGS.4B and 4C show an experimental implementation of the preconcentration system 300 that includes and is configured to interact with a double-tube preconcentration device (e.g., the preconcentrator device 100, 100’, or 200). The evaporation device 310 includes a sample fluid channel defined by the evaporation device 310 from a sample fluid inlet to a sample fluid outlet, similar to the fluid inlets, outlets, and channels elsewhere described.

[0152] The preconcentration system 300 includes a housing 302 enclosing and defining a testing environment 301. The evaporation device 310 is disposed within the testing environment 301 during use. The housing 302 further includes a heater 304, a temperatureAttorney Docket No.10046-586WO1 sensor 306, and a humidity sensor 308. The heater 304 is placed adjacent to the evaporation device 310 (e.g., directly below the evaporation device).

[0153] The preconcentration system 300 further includes a fluid inlet 320 and a fluid outlet 322 defined in the housing 302. A fluid inlet conduit 324 (e.g., an acrylic tube) extends through the fluid inlet 320 to be in fluid communication with the fluid inlet of the evaporation device 310. A fluid outlet conduit 326 (e.g., an acrylic tube) extends through the fluid outlet 322 to be in fluid communication with the fluid outlet of the evaporation device 310. In some implementations, the length of the gas inlet conduit is long enough within the testing environment so that air therein reaches an equilibrium temperature matching that of air already inside the testing environment before it reaches the evaporation device.

[0154] The preconcentration system 300 further includes a gas inlet 330 and a gas outlet 332 defined in the housing 302. A gas inlet conduit 334 (e.g., an acrylic tube) extends through the gas inlet 330 to be in fluid communication with the gas inlet of the evaporation device 310. A gas outlet conduit 336 (e.g., an acrylic tube) extends through the gas outlet 332 to be in fluid communication with the gas outlet of the evaporation device 310. For example, the gas conduit and the fluid conduit may be concentric within the evaporation device – as in the double-tube implementation of this disclosure. However, in other implementations, the gas conduits into and out of the testing environment may be spaced apart from the evaporation device. For example, the gas inlet may produce convective currents within the testing environment rather than extending directly into the evaporation device.

[0155] The preconcentration system 300 further includes a fluid pump 340 coupled to the fluid inlet conduit 324. The fluid pump 340 is configured to cause a flow of sample fluid through the fluid inlet conduit 324, the evaporation device 310, and the fluid outlet conduit 326.

[0156] The preconcentration system 300 further includes a gas pump 342 coupled to the gas inlet conduit 334. The gas pump 342 is configured to cause a gas (e.g., air) flow within the testing environment 301 adjacent to the evaporation device 310. In some implementations, the gas flow runs through the evaporation device.

[0157] A sample collection reservoir 328 is coupled to the fluid outlet conduit 326. The sample collection reservoir 328 collects the concentrated fluid sample once it leaves the testing environment 301. In some implementations, the sample fluid is cycled back through the testing environment 301 to further concentrate the sample.Attorney Docket No.10046-586WO1

[0158] The preconcentration system 300 further includes a controller 350 in communication with each of the heater 304, the temperature sensor 306, the humidity sensor 308, the fluid pump 340 and the gas pump 342. The controller 350 is configured to activate the various elements of the system in response to received instructions and / or values read from sensors. For example, the controller 350 is configured to activate the heater 304 in response to temperature and / or humidity within the testing environment 301. In some implementations, the heater heats the sample fluid to between room temperature and 60 degrees Celsius to avoid breaking down the target analytes.

[0159] The evaporation device 310 is configured to evaporate a solvent of a sample fluid (as elsewhere described in this disclosure) such that the sample fluid exiting the housing 302 has a higher concentration of the target analyze than that of the sample fluid entering the housing 302.

[0160] The housing 302 allows for a closely controlled and monitored testing environment 301. In some implementations, the temperature and / or humidity of the air inside the testing environment is closely controlled to provide for a desired evaporation rate of the solvent. In some implementations, the temperature and / or humidity of the air entering testing environment is closely controlled to provide for a desired evaporation rate of the solvent. In some implementations, the flow rate of the air and / or the sample fluid entering / leaving the testing environment is closely controlled to provide for a desired evaporation rate of the solvent.

[0161] According to another implementation, FIG.4D shows an example system setup for a preconcentrator device (e.g., the device 100’ of FIGS.1G and 1H, or the preconcentrator device 150 of FIGS.1I and 1J). The setup includes a syringe pump connected to the evaporator, where the temperature is precisely regulated. Additionally, the device features an outlet leading to a sealed collection well, which is positioned in ice. This arrangement helps to minimize evaporation from the well. The device's heating system comprises a polyimide heater plate attached to the underside of the heating box, along with a temperature on-off controller. During the evaporation experiments, the temperature inside the heating box is effectively maintained within a narrow margin of 0.2 degrees Celsius of the target temperature. Pure nitrogen gas is used as the sweeping gas, which removes vapor during evaporation in the system. The humidity sensor is positioned after the evaporation process occurs. It continuously monitors the relative humidity of the outlet gas, serving as an evaluation of the evaporation process.Attorney Docket No.10046-586WO1

[0162] The system setup of FIG.4D may be used in situations in which controlled gas access is readily available. For example, when a gas tank or compressed air is available at a known and / or constant humidity level, the system of FIG.4D may be used. A single humidity level sensor is used to determine the evaporation rate as a function of time.

[0163] According to another implementation, FIG.4E shows an example system setup for a preconcentrator device (e.g., the device 100’ of FIGS.1G and 1H, or the preconcentrator device 150 of FIGS.1I and 1J). The system of FIG.4E is substantially similar to the system of FIG.4D except as described below.

[0164] The system of FIG.4E is used when access to a gas tank or compressed air at a known and / or constant humidity level is unavailable. In this case, ambient air is used as the gas in the system. Due to the relatively less predictable nature of ambient air, the system of FIG.4E includes two humidity sensors – one at the gas inlet and one at the gas outlet. The two sensors are used to determine the evaporation rate or factor as a function of time (e.g., via the controller). In other implementations, a volatile organic compound (VOC) sensor may be used in place of the humidity sensor.

[0165] According to another implementation, FIG.4F shows an example system setup for a preconcentrator device (e.g., the device 100’ of FIGS.1G and 1H, or the preconcentrator device 150 of FIGS.1I and 1J). The system of FIG.4F is substantially similar to the system of FIG.4D except as described below. The system of FIG.4F includes a single humidity sensor and is used in situations in which controlled gas access is readily available. However, rather than directing the concentrated sample into a reservoir, the concentrated sample of FIG.4F is directed to an analytical instrument for analysis and / or sample quantification. Thus, the system of FIG.4F allows for on-site sample concentration and analyte detection.

[0166] According to another implementation, FIG.4G shows an example system setup for a preconcentrator device (e.g., the device 100’ of FIGS.1G and 1H, or the preconcentrator device 150 of FIGS.1I and 1J). The system of FIG.4G is substantially similar to the system of FIG.4E except as described below. Similar to FIG.4E, the system of FIG.4G is used when access to a gas tank or compressed air at a known and / or constant humidity level is unavailable. Thus, FIG.4G includes two humidity sensors. Additionally, similar to FIG.4F, the system of FIG.4G directs the concentrated sample to an analytical instrument for analysis and / or sample quantification. Various combinations and permutations of the disclosedAttorney Docket No.10046-586WO1 devices, flow paths, and instruments shown and described in the disclosed systems are further contemplated by this disclosure.

[0167] FIG.4H shows an another example preconcentration system as a portable preconcentration system 360, according to one implementation. The portable preconcentration system 360 includes an integrated air pump, a custom printed circuit board (PCB) with consolidated electronics, and other features that enable the system 360 to operate as a standalone, fully portable device.

[0168] To ensure efficient heat transfer, the system 360 includes an inner housing 361 and an outer enclosure 362. The inner housing 361 includes a metal material, such as aluminum. The outer enclosure 362 includes an inert and / or insulative material, such as plastic (e.g., 3D printed plastic such as polylactic acid (PLA) or Polyethylene terephthalate glycol (PETG) material). The outer enclosure 362 provides thermal insulation for the inner housing 361, preventing a user from touching the high-temperature surfaces of the metal inner housing 361. The inner housing 361 defines an inner cavity. The inner cavity includes the preconcentrator device (e.g., the double- or multi-tube preconcentrator device or other preconcentrator devices herein described).

[0169] A heat plate is mounted at the bottom of the inner housing 361 (e.g., the cavity of the metal box), where the evaporation preconcentrator is housed. Since the temperature controller (W1209) operates as an on-off system and the heat plate can reach up to 150^°C— while the melting point of PLA is approximately 180^°C—it would be unsafe to allow direct contact between PLA components and the heat plate. Therefore, a platform suspends the heat plate in air, preventing direct contact with PLA parts. The plate heats the gas in the cavity, which further heats the preconcentrator device and its associated elements. Heating the ingoing gas also helps to avoid heat transfer between the liquid and the sweeping gas in the preconcentrator device.

[0170] The system 360 is couplable to a sample fluid tube (e.g., acrylic tubing with a syringe pump, not shown). The sample fluid travels along the “liquid flow path” shown in FIG.4H. Specifically, the sample fluid enters the inner cavity and the preconcentrator device therein at the sample fluid inlet 364. The sample fluid inlet 364 is in fluid communication with the preconcentrator device, which is further in fluid communication with a sample fluid outlet 366. The sample fluid outlet 366 may be coupled to a collection chamber to collect the concentrated sample.Attorney Docket No.10046-586WO1

[0171] The overall dimensions of the portable device box of the system 360 are 139.8 × 48.8 × 110.0 mm. The system 360 minimizes the direction in liquid flow, which helps reduce the volume required in the tubing. Another method to minimize flow volume is by using thinner tubing. In some examples, the liquid tubing has an inner diameter (ID) of 1 / 64" and an outer diameter (OD) of 1 / 16", which is a common size for connections to flow cells and collection wells.

[0172] The system 360 further includes a pump 368 coupled to a platform extending from the outer enclosure 362. The pump 368 is an air pump configured to collect and pressurize air from the environment for use in the preconcentrator device. To prevent fatigue in the overall device, the vibration generated by the pump 368 must be considered. Instead of screwing the pump 368 directly to the box, vibration-control pads are placed both beneath the pump 368 and along the vertical mounting surface (where several mounting holes are visible), to minimize vibration transmission.

[0173] The system 360 further includes a first gas box 370 and a second gas box 372. A gas tube is coupled between the pump 368 and an inlet of the first gas box 370. Additional gas tubes are coupled between each of the outlet of the first gas box 370, an inlet of the preconcentrator device in the cavity, an outlet off the preconcentrator device in the cavity, and an inlet of the second gas box 372. In some examples, the gas tubing has an ID of 1 / 8" to ensure compatibility with both the D260 pump and the preconcentrator.

[0174] The first and second gas boxes 370, 372 include one or more sensors, such as temperature and humidity sensors. The gas entering the first gas box 370 is analyzed, and the associated values are fed to the controller. Similar to the controller 350, the controller of the system 360 is configured to activate the various elements of the system in response to received instructions and / or values read from sensors. The second gas box 372 is provided to analyze the output gas (e.g., the humidity thereof), which can inform the efficiency of the system 360.

[0175] To ensure accurate humidity readings, the humidity sensors are placed in the same temperature environment as the gas flow, since relative humidity is a temperature-dependent parameter. Maintaining a consistent temperature helps improve data accuracy and also facilitates future replacement with humidity sensors that do not have built-in temperature sensing.Attorney Docket No.10046-586WO1

[0176] FIG.5 shows a flow chart illustrating a control system and method for a preconcentration system of this disclosure, according to one implementation. For example, the flow chart of FIG.5 may illustrate the operation of the system 300 and the corresponding controller 350. Step 401 includes providing a preconcentration system (e.g., the system 300 shown and described in FIGS.4A-4G).

[0177] The method further includes setting initialization parameters. For example, at step 402, the controller receives a desired evaporation rate or factor via user input. The desired evaporation rate may be a particular rate based on the solvent or sample fluid (e.g., a rate stored in the memory of the controller). In other implementations, the desired evaporation rate input by the user may be a more generic level or value that is adjusted based on measured environmental factors (e.g., temperature and humidity). As an alternative, at step 403, the controller may calculate the desired evaporation rate or factor based on the measured values of temperature and humidity (e.g., via a stored correction factor). The desired evaporation rate or factor may also be associated with a particular flow rate of the sample fluid and / or the gas.

[0178] At step 404, the controller initiates the pump of the system to cause a gas to flow within the testing environment defined by the housing. At step 405, the controller initiates the heater of the system to adjust the temperature of the testing environment. Both steps 404 and 405 are informed by the desired evaporation rate from steps 402 and / or 403. Steps 404 and 405 may be performed simultaneously or in opposite order.

[0179] At step 406, the controller initiates a pump to cause the sample fluid to flow through the evaporation device, initiating the evaporation and sample concentration process. At step 407, the system begins collecting the concentrated sample fluid (e.g., in a collection vial in fluid communication with a sample fluid outlet conduit). In some implementations, the concentrated sample fluid collection step is not performed until after a desired evaporation level is reached.

[0180] At step 408, the controller monitors various aspects of the system to verify operation is within the expected parameters. The controller may monitor humidity, temperature, flow rates of gas or sample fluid, timing of the various elements (e.g., on time / off time), volume of fluid collected, volume of fluid input, or other relevant factors. In some implementations, a user interface or display on the outside of the housing may be usedAttorney Docket No.10046-586WO1 to monitor and display various sensor values and evaporation rates. In some implementations, the housing includes a viewing window.

[0181] At step 409, the controller operates a feedback loop wherein one or more of (i) the flow rate of the gas, (ii) the flow rate of the sample fluid, or (iii) the power of the heater are adjusted based on values from the humidity and temperature sensors in the testing environment. If any one of the monitored values in step 408 is out of the expected range, the controller will initiate one of the adjustable elements (e.g., heater or pump) to bring the value back into a normal range. If all of the parameters meet the expected values, then the controller operates the system as normal.

[0182] At step 410, the controller checks whether or not a stop signal / condition is reached. For example, the system may operate until a desired concentration of the target analyte is reached. In some implementations, the system may continue to evaporate solvent until the volume of the sample has decreased to a desired volume representative of a higher concentration. Until a stop condition is detected, the system continues normal operation and monitoring of parameters. Once a stop condition is detected, the system stops operation.

[0183] The concentrated sample fluid can then be used for analysis and performing various tests. In some implementation, the evaporation device may be removed, washed, and reused in an additional preconcentration operation. Experimental Testing and Results #1

[0184] Studies were conducted utilizing a preconcentration device (e.g., the device 100’ of FIGS.1G-1H) and a system for preconcentration (e.g., the systems of FIGS.4A-4G). The individual studies, experiments, and resulting data are exemplary only and do not limit the scope of the device, system, or methods of the present disclosure. The individual target analytes, molecules, compounds, particles, or other target matter – along with the fluid or solvent associated therewith – that are described in the experimental sections below or elsewhere described are provided as non-limiting examples only and do not limit the scope of the disclosure.

[0185] The evaporator device (e.g., the preconcentrator of FIGS.1G and 1H) was fabricated via micro-3D printing for investigation in a study. The evaporator could operate at low temperatures, which are favorable for some biomolecules, and could handle micro- volume samples as small as tens to hundreds of microliters. The example design included an inner tube with evaporation holes (e.g., micro-holes) through which the solution is injected,Attorney Docket No.10046-586WO1 and an outer tube through which drying gas is flown. The diameter of the inner tube was only 400 µm, on which 50 µm sized evaporation holes / pores are positioned for facilitating evaporation. The theoretical evaporation rate from the meniscus shape of a single evaporation hole (e.g., micro-pore) was calculated, and a method employing a relative humidity sensor for estimating total evaporation over time was demonstrated in this study. Evaporation and concentration experiments were conducted with deionized water and also with aqueous glucose solutions. The study achieved controlled evaporation, attaining a concentration factor of up to 13-fold with an accuracy of ±5%. The evaporator concentrator can be used to enrich aqueous-soluble molecules as well as aqueous-insoluble particles.

[0186] Materials and Methods

[0187] The experimental device was fabricated using a 3D printer (S230, Boston Micro Fabrication) with a BMF MED resin, which is a rigid, amber-colored, and biocompatible material. FIG.6A shows an image of the device next to a ruler. The image of the inner tube from a microscope, showing the individual evaporation holes (e.g., micro-pores), is shown FIG.6B. It can be seen that the pore sizes are within the example required dimensions (e.g., 53.5±6.4 μm) and also that they are not completely round in this experimental implementation. The space between the evaporation holes (e.g., micro-pores) in this experimental example is 236.4±9.8 mm.

[0188] FIG.4D shows a schematic of the experimental setup used for testing the device. The setup includes a syringe pump connected to the evaporator, where the temperature is precisely regulated. Additionally, the device features an outlet leading to a sealed collection well, which is positioned in ice. This arrangement helps to minimize evaporation from the well. The device's heating system comprises a polyimide heater plate attached to the underside of the heating box, along with a temperature on-off controller (W1209). During the evaporation experiments, the temperature inside the heating box is effectively maintained within a narrow margin of 0.2 degrees Celsius of the target temperature. Pure nitrogen gas (Airgas, ultra-high purity: >99.999%) is used as the sweeping gas, which removes vapor during evaporation in the system. The humidity sensor (SHT41, Sensirion) is positioned after the evaporation process occurs. It continuously monitors the relative humidity of the outlet gas, serving as an evaluation of the evaporation process.

[0189] To obtain a preliminary understanding of the evaporation efficiency of this device, deionized water was initially used in evaporation experiments. Extracting a volume of 1000Attorney Docket No.10046-586WO1 μL through continuous constant-rate injections and measuring the remaining weight after evaporation enables the calculation of the evaporation volume. The water evaporation experiment is also used to calculate the evaporation ratio and concentration factor under specific evaporation parameters.

[0190] Various concentrations of glucose solutions were produced through serial dilution. The study first weighed and dissolved glucose in deionized water to prepare a 100 mmol / L solution. The study diluted the glucose solution to concentrations of 10, 20, and 40 mmol / L by mixing it with deionized water, which were then used for subsequent spectrum peak calibration. The solution to be concentrated at the inlet is the 10 mmol / L glucose solution.

[0191] The evaporation process of glucose solution follows the same protocol as that of deionized water, with the glucose concentration measured using a Fourier Transform Infrared (FTIR) spectrometer (iS50, ThermoFisher). Spectral data were uniformly acquired in transmittance mode using a liquid flow cell with a fixed path length of 50 μm. Each recorded spectrum, ranging from 400 to 4000 cm-1, was a composite average of 256 individual scans, obtained at a resolution of 0.482 cm-1. To maintain measurement integrity, the flow cell was rinsed with deionized water for 1 minute after each use. Data were collected in single-beam mode. Calculations of absorbance values were subsequently performed during the data processing phase. Notably, spectra of deionized water were systematically recorded as both initial and final measurements within each series. This practice allows for a comparative analysis between these two endpoint spectra, thereby ensuring the consistency and minimal bias of the intermediate measurements. The concentration of glucose samples can be calculated from specific peak heights compared to a calibration curve, given that the peak height is a linear function of concentration.

[0192] Results and Discussion

[0193] FIG.7A illustrates the relative humidity and the corresponding minimum liquid feeding rate at different dry nitrogen gas flow rates at 30℃. The liquid flow rate was fixed and sufficient for the maximum dry nitrogen gas flow rate used in the experiment. The process can be modeled as a mixture process: dry nitrogen gas and evaporated water vapor are mixed in the micro-3D printed channel, and the mixture is expelled by the continuous gas flow. The error bars of relative humidity calibration in FIG.7A fall within a reasonable range, primarily due to the humidity in the surrounding environment. This indicates that the method is highly repeatable and reliable for theoretical evaporation calculations.Attorney Docket No.10046-586WO1

[0194] During the same calibration process, the study determined the minimum liquid flow required for each dry nitrogen gas flow rate. The minimum liquid flow rate represents the lowest volumetric flow rate of the liquid solution at a specific temperature and sweeping gas flow rate. Since the evaporation rate correlates with the sweeping gas flow rate, each gas flow rate has a corresponding minimum liquid flow rate. Intuitively, a higher gas flow rate results in a higher evaporation ratio, which also sets the minimum liquid flow rate. FIG.7B illustrates the minimum liquid flow rate for each dry nitrogen gas flow rate at 30℃. The usable range is above the curve, while the area below indicating complete evaporation. For instance, at 30°C with a dry nitrogen gas flow rate set to 60 mL / min, the minimum liquid flow rate is 0.99 μL / min. If the actual experimental liquid flow is less than 0.99 μL / min, all injected liquid will evaporate. Solution can only be obtained from the evaporator outlet when the liquid flow exceeds the minimum liquid flow rate.

[0195] As observed in FIG.7A, the relative humidity increases as the dry nitrogen gas flow rate decreases. This can be explained by the fact that with a slower gas flow rate, water evaporates more thoroughly, thus the sweeping gas carries more water vapor. Conversely, with a faster gas flow rate, less water vapor is carried, and the mixture tends to exhibit characteristics of dry nitrogen gas, resulting in lower relative humidity.

[0196] In a fixed-dimension evaporator, three critical independent variables are the liquid sample flow rate, sweeping gas flow rate, and temperature, while the relative humidity is consistently recorded. FIGS.7C and 7D illustrates how liquid flow rates, temperature and sweeping gas flow rate influence the evaporation process. Specifically, FIG.7C shows evaporation ratio and concentration factor as a function of temperature for various liquid flow rates, with contact sweeping gas flow rate of 50 mL / min. FIG.7D shows evaporation ratio and concentration factor for different sweeping gas flow rates, with constant temperature of 30℃ and liquid flow rate of 1.0 μL / min. Increasing the liquid flow rate decreases the residence time of a specific volume of liquid in the evaporation area, thus reducing evaporation. Moreover, an increase in temperature raises the saturation pressure of water vapor, thereby enhancing the pressure gradient between the sweeping gas and the liquid-gas interface, ultimately resulting in faster evaporation. Furthermore, a higher sweeping gas flow rate enhances vapor removal, thereby increasing the vapor pressure difference between the gas channel and the liquid surface, which in turn accelerates evaporation. The highest evaporation ratio in FIG.7C is 0.925, occurring at a 1.0 μL / min liquid flow rate (the lowestAttorney Docket No.10046-586WO1 rate tested in our research), 40℃, and a gas flow rate of 50 mL / min, where the corresponding concentration factor is 13.3 calculated using Equation 6.

[0197] The data can be used to optimize the operating conditions for maximum efficiency. Determining the optimal combination of temperature and flow rates that yields the desired evaporation ratio could be crucial for practical applications. For instance, to concentrate a sample with a degradation temperature of 40°C, requiring an evaporation ratio of at least 0.2, FIG.7C suggests using conditions of 30°C, a 2.5 μL / min liquid flow rate, and a 50 mL / min gas flow rate.

[0198] FIGS.7E and 7F present both theoretical and experimental values of the evaporation ratio and concentration factor from the deionized water evaporation experiment. Specifically, the figures show deionized water evaporation and corresponding concentration factors under experimental conditions of 30°C temperature and a 50 mL / min dry nitrogen gas flow rate wherein FIG.7E shows evaporation ratio versus liquid flow rate from 1 to 10 μL / min and FIG.7F shows concentration factor versus liquid flow rate from 1 to 10 μL / min.

[0199] The evaporation ratio is defined as the amount of liquid evaporated relative to the total amount of liquid injected. Furthermore, the concentration factor represents the ratio of the analyte's concentration after evaporation to its original concentration. It is assumed that the analyte is soluble in water and does not degrade during the concentration process. The theoretical evaporation ratio and concentration factor are calculated using equation 5 and equation 6, respectively.

[0200] The experimental evaporation ratios and concentration factors closely match theoretical calculations, particularly at higher liquid flow rates. This confirms the theory's close approximation of the actual evaporation process. However, at lower flow rates, a larger bias is observed. This is primarily because at lower flow rates, a longer time is required to pass the same total volume of liquid, potentially increasing uncertainties during evaporation. Additionally, approximations in experimental values may accumulate, leading to greater errors over time.

[0201] FIG.7G shows a graph of FTIR absorbance spectra of glucose at concentrations of 10, 20, and 40 mmol / L, together with those of two preconcentrated samples (Sample 1 and Sample 2). FIG.7H shows a calibration curve derived from peak heights at 1036 cm-1for known glucose concentrations (10, 20, and 40 mmol / L), including peak height comparisons for two preconcentrated samples.Attorney Docket No.10046-586WO1

[0202] FIG.7G shows distinct peaks at specific wavenumbers (1036, 1080, 1108, and 1152 cm-1). These peaks, characteristic of glucose, are used to quantify its concentration. Peak height is calculated by subtracting a baseline from the maximum near the specific wavenumber. Baseline is selected to be the average absorbance around 1190 cm-1, where most spectra are flat and overlap. The linear fit equation with a high coefficient of determination (R2 > 0.99) in FIG.7H indicate a strong linear relationship between peak height and glucose concentration, as expected from the Beer Lambert law.

[0203] An aqueous glucose concentration of 10 mmol / L was prepared. After passing though the concentrator, the concentration of glucose in the outlet was measured using FTIR. Sample 1 was obtained for conditions of 1 μL / min sample flow rate and Sample 2 was obtained for conditions of 2.5 μL / min sample flow rate. These two samples are also plotted on the calibration curve in FIG.7H, allowing estimation of their concentrations based on the linear relationship. From the linear fit of the known concentrations of aqueous glucose solutions, the glucose concentration of Sample 1 and 2 in the outlet can be estimated, yielding 25.1 mmol / L and 13.0 mmol / L, respectively. Using these results, the concentration factors were calculated by dividing the outlet concentrations by the initial concentrations; the concentration factors for Sample 1 and Sample 2 were 2.51 and 1.30, respectively.

[0204] As shown in FIG.7H, the absorbance peak height at 1036 cm-1was used to demonstrate the relationship between concentration and absorbance. However, the spectra also show other significant peaks, which could also be used for similar quantitative analyses. Exploring multiple peaks could provide a more robust validation of the data, as differences in peak behavior might reveal additional information about the molecular environment or the interaction between molecules at different concentrations. Moreover, analyzing multiple peaks can help in verifying the reproducibility and reliability of the spectroscopic method across different spectral features, enhancing the overall accuracy of the concentration measurements.

[0205] Concentration factors have been obtain using theoretical analysis, using reduction in weight of deionized water and increase in concentration of a glucose solution. These are summarized in Table 1. There are slight differences in the concentration factors between the three methods. The theoretical value is the highest because, under ideal conditions, evaporation can reach its maximum theoretical limit; The concentration measured by FTIR is the lowest and is also the closest to the actual concentration because, unlike other methods that involve calculations, FTIR directly measures the concentration, making its results moreAttorney Docket No.10046-586WO1 reliable.; and the concentration factor from the deionized water experiment is intermediate, indicating that the underlying assumptions are more reflective of reality. However, assuming that the sample maintains constant density during the evaporation process may introduce a larger bias, particularly at lower liquid flow rates. Sample details Theoretical CF from CF from CF deionized water FTIR ent, measurements.

[0206] An additional study analyzed the flat channel, membrane-inclusive preconcentrator device 200 of FIGS.3A-3E. The study was conducted specific to the gas permeable layers of the “flat” microfluidic channel implementation of the evaporation / preconcentration device. For example, see the device of FIG.3D. For that experiment, the evaporation percentage was calculated as the difference in the weight of the device (and water) before and after the experiment. A static evaporation test was performed on a heat plate at 60 C.

[0207] FIG.8A shows the results of the static evaporation test without PDMS in the gas permeable layer. As shown, evaporation percentage increases with increased time and temperature, respectively. FIG.8B shows the results of the static evaporation test with PDMS in the gas permeable layer. Similar trends are observed, although the total evaporation rate was lower for each trial including the PDMS. The two experiments are compared in the graph in FIG.8C, showing the “without PDMS” line above the “with PDMS” line.

[0208] A study was conducted to investigate the relative humidity of sweeping gas in the preconcentrator devices and / or systems disclosed herein. In a portable device designed to operate under various environmental conditions, ambient air with varying humidity levels will be used as the sweeping gas. Therefore, it is helpful to understand how the relative humidity of the sweeping gas affects evaporation. As described in the portableAttorney Docket No.10046-586WO1 preconcentration system described herein, two humidity sensors may be integrated to continuously monitor the relative humidity of the gas before and after the preconcentrator.

[0209] FIG.9A shows the evaporation ratio at relative humidities ranging from 0% to 80% and liquid flow rates from 1 to 10^μL / min. FIG.9B illustrates the linear relationship between the evaporation ratio and the humidity difference before and after the preconcentrator, which is consistent with the theoretical equation (Equation 5). Preconcentration Applications and Experimental Results

[0210] Detection of perfluorinated compounds (PFCs), also known as perfluoroalkyl and polyfluoroalkyl substances (PFAS), and “forever chemicals” in water and the environment is important but very challenging. Preconcentration, such as through the systems, methods, and devices disclosed herein, will improve detection capabilities. An experimental study was conducted to verify preconcentration of forever chemicals.

[0211] Infrared spectrum of PFBS: Infrared spectroscopy can be used for perfluorobutanesulfonic acid (PFBS) detection because PFBS contains strong sulfonic acid and C–F bonds that exhibit distinct and identifiable absorption peaks in the infrared region. Same with other PFAS compounds. FIG.10A shows the infrared spectrum for PFBS between 1000-1400 cm-1collected during this study. The peak at 1064 cm-1corresponds to the asymmetric stretching vibration of the sulfonate (-SO₃) group, a characteristic feature of sulfonic acids and sulfonate groups in PFBS. Peaks for C-F bond usually appears between 1000-1360 cm-1, so the peaks around 1140 cm-1and 1217 cm-1is assigned as symmetric and asymmetric stretching vibrations of –CF2 bond. The most prominent waveband at 1255 cm-1corresponds to the stretching vibration band for –CF3bond. The peak at 1354 cm-1can be assigned to the bending vibration band for O-H group.

[0212] Fourier Transform Infrared (FTIR) Spectroscopy Calibration Curve: A calibration curve was created by collecting infrared spectra of 5000 ppm, 2500 ppm, 1000 ppm, 500 ppm, 250 ppm, and 100 ppm. FIG.10B shows collected spectra for different PFBS concentration. FIG.10C demonstrates a linear relationship between the PFBS concentration and the absorbance peak height at 1255 cm-1. This is expected according to the Beer-Lambert law, which states that absorbance of the chemical substance is directly proportional to its concentration. The absorbance intensity for 100 ppm PFBS sample is very low indicating that the detection limit for the FTIR is reached.Attorney Docket No.10046-586WO1

[0213] Preconcentration experiment: The preconcentration process was conducted under varying experimental parameters to evaluate its effectiveness using the single-tube preconcentrator, which features 50^μm diameter pores with 250^μm spacing between adjacent pores, and all other design details described in the previous document remaining the same. In the 250 ppm experiment, as shown in FIG.10D, the conditions included a temperature of 42°C, a nitrogen flow rate of 50 mL / min, and a sample flow rate of 3 μL / min. Calculated from the calibration curve shown in FIG.10C, this process achieved a final concentration of 312 ppm, resulting in an overall concentration factor of approximately 1.25.

[0214] Similarly, the 100 ppm experiment, shown in FIG.10E, employed a similar temperature of 42°C but with a nitrogen flow rate of 60 mL / min and a reduced sample flow rate of 1.2 μL / min. This process produced a final concentrated sample of 4800 ppm, yielding significantly higher concentration factor of 48.

[0215] These results demonstrate that the preconcentrator exhibits excellent enrichment performance for PFBS, achieving concentration factors ranging from 1.25 to 48 under various evaporation parameters. Evaporation experiments with lower concentration factors contribute to a better understanding of the effects of various parameters in evaporation processes. By integrating experimental data with computational analysis and simulations, a series of evaporation experiments can more effectively enable precise control over the evaporation process.

[0216] High concentration factors are of greater research significance and practical application. Observing the results, it becomes evident that PFBS at very low concentrations (<100 ppm) is challenging to detect using conventional FTIR methods. However, after enrichment with the preconcentrator, detection becomes easier. This process demonstrates that, with a known concentration factor (typically determined by evaporation parameters), the initial concentration of the sample can be inferred from the enriched concentration. This approach enables accurate estimation of low-concentration samples.

[0217] During the experiment, it was observed that PFBS tends to adhere to various surfaces, such as weighing paper, vials, and spatulas. Although PFBS appears as a white powder in its container, it turns into a sticky, liquid-like substance upon contact with other materials. This behavior poses a potential issue for the system, as some PFBS may adhere to components like the syringe pump, tubing, or collection well during the evaporation process. To assess the extent of this loss, a control experiment was conducted by flowing a 100 ppmAttorney Docket No.10046-586WO1 PFBS solution through the same setup, excluding the preconcentrator, but including the syringe pump, tubing, and collection well. The goal was to determine how much PFBS was lost due to surface adhesion. The experiments showed that there was no measurable difference in absorbance between the original 100 ppm stock solution and the solution collected after the experiment. This indicates that there was no significant sorption of the compound inside the tubes under the tested conditions: 42^°C, a nitrogen flow rate of 60^mL / min, and a sample flow rate of 1.2^μL / min. While this suggests minimal interaction between PFBS and the tubing material under these specific conditions, further studies are needed to determine whether this behavior holds under a broader range of operating parameters.

[0218] The following section discusses the preconcentrator devices and systems along with their enrichment performance for glucose, lactate, and pyruvate, which are important biomarkers for example for patients with traumatic brain injury (TBI). Table 2, blow, shows key physicochemical properties of glucose, lactate, and pyruvate relevant to evaporation- based preconcentration. Property Glucose Lactate (Lactic Pyruvate (PyruvicAttorney Docket No.10046-586WO1 Hydrophilicity / -3.24 -0.72 -0.25 LogP

[02] . - s ow e a sor ance spec ra o gucose, ac a e, an pyruvate after preconcentration at 30^°C, with a sample flow rate of 1^μL / min and an air flow rate of 20^mL / min. Specifically, FIG.11A shows the results for glucose, FIG.11B shows the results for lactate, and FIG.11C shows the results for pyruvate. Three trials were performed under relative humidities of 9.3%, 9.4%, and 9.4%, respectively, all starting from 10^mM solutions. The resulting spectra are compared with those of 10^mM and 20^mM standard solutions. The solvent used was a perfusion fluid containing 147^mM NaCl, 2.7^mM KCl, 1.2^mM CaCl₂, and 0.85^mM MgCl₂, dissolved in ultrapure water (18.2^MΩ·cm).

[0220] One concern is that the lactate peak at 1041 cm⁻¹ does not yield concentrations consistent with those obtained from the 1124 cm⁻¹ peak. Figure 11D presents the calibration curve based on the absorbance peak height at 1041 cm⁻¹. According to this calibration, the concentrations of lactate samples 1–3 are 21.14, 19.69, and 17.38 mM, respectively. The corresponding calculated concentration factor is 1.94^±^0.19. Peak Original After Concentration CF fromAttorney Docket No.10046-586WO1 Table 3. Concentration factors measured by FTIR in all preconcentration trials and the result from the evaporation experiment using water. Configuration of Certain Implementations

[0221] The construction and arrangement of the systems and methods as shown in the various implementations are illustrative only. Although only a few implementations have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes, and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.). For example, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present disclosure. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative implementations. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the implementations without departing from the scope of the present disclosure.

[0222] Although the figures show a specific order of method steps, the order of the steps may differ from what is depicted. Also, two or more steps may be performed concurrently or with partial concurrence. Such variation will depend on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps and decision steps.

[0223] It is to be understood that the methods and systems are not limited to specific synthetic methods, specific components, or to particular compositions. It is also to be understood that the terminology used herein is for the purpose of describing particular implementations only and is not intended to be limiting.

[0224] As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another implementation includes from the one particular value and / or to the other particular value. Similarly, when values are expressed asAttorney Docket No.10046-586WO1 approximations, by use of the antecedent “about,” it will be understood that the particular value forms another implementation. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0225] “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal implementation. “Such as” is not used in a restrictive sense, but for explanatory purposes.

[0226] Disclosed are components that can be used to perform the disclosed methods and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific implementation or combination of implementations of the disclosed methods.

Claims

Attorney Docket No.10046-586WO1 WHAT IS CLAIMED IS:

1. A preconcentration system comprising: an evaporation device comprising a sample fluid channel defined by the evaporation device and extending from a sample fluid inlet to a sample fluid outlet, the evaporation device configured to evaporate a solvent of a sample fluid containing a target analyte such that the sample fluid exiting the sample fluid outlet has a higher concentration of the target analyte than that of the sample fluid entering the sample fluid inlet; a housing enclosing and defining a testing environment within which the evaporation device is disposed, the housing comprising a heater, a temperature sensor, and a humidity sensor each disposed within the testing environment; a pump coupled to a gas inlet tube in fluid communication with the testing environment, the pump configured to cause a gas flow within the testing environment adjacent to the evaporation device; and a controller in communication with each of the heater, the temperature sensor, and the humidity sensor, the controller configured to activate the heater in response to at least one of a temperature value or a humidity value of the testing environment.

2. The preconcentration system of claim 1, wherein the evaporation device comprises: a gas tube defining a gas channel extending from a gas inlet to a gas outlet, the gas channel coupled to and in fluid communication with the gas inlet tube; and a sample fluid tube defining the sample fluid channel, the sample fluid tube disposed within at least a portion of the gas channel with a radial gap defined between an inner surface of the gas tube and an outer surface of the sample fluid tube, wherein the radial gap is configured for a gas to flow around and adjacent to the sample fluid tube, wherein a length of the sample fluid tube defines a plurality of evaporation holes extending radially outward from an inner surface of the sample fluid tube to the outer surface of the sample fluid tube such that the sample fluid channel is in fluid communication with the gas channel.

3. The preconcentration system of claim 2, wherein the plurality of evaporation holes have a predefined density defined by a number of evaporation holes per area of the outer surface of the sample fluid tube.Attorney Docket No.10046-586WO1 4. The preconcentration system of claim 2, wherein the plurality of evaporation holes have a diameter in the range of 0.1 nanometers to 500 micrometers, inclusive.

5. The preconcentration system of claim 2, wherein the sample fluid tube and the gas channel are coaxial.

6. The preconcentration system of claim 2, wherein the evaporation device comprises a plurality of sample fluid channels in fluid communication with the sample fluid inlet and the sample fluid outlet, wherein the sample fluid tube comprises a first sample fluid tube and a second sample fluid tube, each extending parallel to each other in at least a portion of the gas channel.

7. The preconcentration system of claim 6, wherein the sample fluid tube comprises four separate sample fluid tubes each defining a portion of the sample fluid channel, wherein the four separate sample fluid tubes converge and combine adjacent to both the sample fluid inlet and the sample fluid outlet.

8. The preconcentration system of claim 1, wherein the evaporation device comprises a plurality of sample fluid channels in fluid communication with the sample fluid inlet and the sample fluid outlet.

9. The preconcentration system of claim 1, wherein the evaporation device comprises: a lower body defining the sample fluid channel; and a gas permeable membrane disposed on an upper surface of the lower body; and a lid coupled to the lower body to retain the gas permeable membrane in place, the lid defining an evaporation opening aligned with the sample fluid channel of the lower body such that the solvent of the sample fluid evaporates through the gas permeable membrane, through the evaporation opening, and into the testing environment.

10. The preconcentration system of claim 1, wherein the controller is communication with the pump and configured to activate the pump to adjust a flowrate of the gas through the gas inlet tube.

11. The preconcentration system of claim 1, wherein the housing defines:Attorney Docket No.10046-586WO1 (i) a first inlet for a sample fluid inlet tube in fluid communication with the sample fluid inlet of the evaporation device; (ii) a first outlet for a sample fluid outlet tube in fluid communication with the sample fluid outlet of the evaporation device; (iii) a second inlet for the gas inlet tube; and (iv) a second outlet for a gas outlet tube.

12. The preconcentration system of claim 11, further comprising a collection container for the concentrated sample fluid exiting the housing coupled to the sample fluid outlet tube.

13. The preconcentration system of claim 1, wherein the target analyte is at least one of glucose, lactate, or pyruvate and the sample fluid is a brain fluid.

14. The preconcentration system of claim 1, wherein the target analyte is a DNA or RNA sample in a polymerase chain reaction (PCR) process.

15. A preconcentrator device comprising: a sample fluid tube defining a sample fluid channel extending from a first end to a second end of the sample fluid tube, the sample fluid tube comprising a plurality of evaporation holes extending radially from an inner surface of the sample fluid tube to an outer surface of the sample fluid tube, wherein the device is configured to flow a sample fluid containing a target analyte and a solvent through the sample fluid channel from the first end to the second end; and a gas tube defining a gas channel extending from a first end to a second end of the gas tube, wherein the device is configured to flow a gas through the gas channel from the first end to the second end, wherein the sample fluid tube disposed within the gas channel of the gas tube, and the outer surface of the sample fluid tube is spaced apart from an inner surface of the gas tube, wherein the device is configured to evaporate the solvent through the plurality of evaporation holes and into the gas channel to concentrate the target analyte of the sample fluid.Attorney Docket No.10046-586WO1 16. The preconcentrator device of claim 15, wherein the first and second ends of the gas tube extend substantially perpendicularly with respect to the first and second ends of the sample fluid tube.

17. The preconcentrator device of claim 15, further comprising a plurality of sample fluid tubes disposed within the gas channel.

18. The preconcentrator device of claim 17, wherein each of the plurality of sample fluid tubes are in fluid communication with an inlet defined on the first end of the sample fluid tube and an outlet defined on the second end of the sample fluid tube.

19. The preconcentrator device of claim 15, wherein the sample fluid tube comprises a first sample fluid tube and a second sample fluid tube each extending parallel to each other in at least a portion of the gas channel.

20. The preconcentrator device of claim 15, wherein the sample fluid tube comprises four separate sample fluid tubes each defining a portion of the sample fluid channel, wherein the four separate sample fluid tubes converge and combine adjacent to both a sample fluid inlet on the first end and a sample fluid outlet on the second end.

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