Microfluidic sensor for monitoring total organic carbon in dialysis systems

Abstract

A system for measuring a total organic carbon level in a fluid may include a first conduit, an inlet sensor to sense at least one first property of a fluid at the first conduit, a microfluidic enclosure disposed fluidly downstream of the first conduit, the microfluidic enclosure including a housing having an inlet and an outlet, a microfluidic sample cell at least partially transparent to light radiation, and an energy source configured to output radiation to the microfluidic sample cell, a second conduit fluidly connected to the outlet, and an outlet sensor configured to sense at least one second property of the fluid as received from the microfluidic enclosure. The inlet sensor and the outlet sensor can sense one or more other properties of the fluid including at least one of electrical conductivity, pH, temperature, and ultraviolet absorption.

Description

Attorney Docket No. 218079.023801 (IDF00022)MICROFLUIDIC SENSOR FOR MONITORING TOTAL ORGANIC CARBON IN DIALYSIS SYSTEMSCROSS REFERENCE

[0001] This application claims the benefit and priority to U.S. Provisional Application No.63 / 721,231, filed on November 15, 2024, and titled “MICROFLUIDIC SENSOR FOR MONITORING TOTAL ORGANIC CARBON IN DIALYSIS SYSTEMS”, the entire content of which is incorporated by reference herein.FIELD

[0002] The present disclosure relates to the field of dialysis systems. More particularly, the disclosure relates to microfluidic sensors for total organic carbon measurement in dialysis systems.BACKGROUND

[0003] Peritoneal dialysis systems can utilize a high volume of dialysis fluid for treatment.The dialysis fluid typically includes ultra purified water and one or more additives. Peritoneal dialysis systems can oftentimes include water purification systems that produce purified water, which is then mixed with the additives to form the dialysis fluid for therapy. To meet Pharmacopeia standards, the purified water used in peritoneal dialysis systems should have a Total Organic Carbon (“TOC”) level below a certain threshold.SUMMARY

[0004] In some embodiments, a system includes a first conduit, an inlet sensor configured to sense a first property of a fluid flowing through the first conduit, a microfluidic enclosure fluidly connected to the first conduit, the microfluidic enclosure being disposed fluidly downstream of the inlet sensor, and the microfluidic enclosure including a housing having an inlet and an outlet, a microfluidic sample cell disposed within the housing, the microfluidic sample cell being at least partially transparent to ultraviolet radiation, the inlet being fluidly connected to the firstAttorney Docket No. 218079.023801 (IDF00022)conduit, and an ultraviolet source disposed within the housing and configured to output ultraviolet radiation, a second conduit fluidly connected to the outlet, and an outlet sensor configured to sense a second property of the fluid as received from the microfluidic enclosure and disposed downstream of the microfluidic enclosure.

[0005] In some embodiments, the inlet sensor is a first conductivity sensor, and the outlet sensor is a second conductivity sensor.

[0006] In some embodiments, the system further includes a controller, the controller being configured to receive the first property, the first property being a first conductivity, receive the second property, the second property being a second conductivity, and determine a total organic carbon (TOC) within the fluid using a difference between the first property and the second property.

[0007] In some embodiments, the controller is configured to determine the TOC within the fluid using the first property as sensed and adjusted using another property such as, but not limited to, temperature, and the second property as sensed and adjusted using another property such as, but not limited to, temperature.

[0008] In some embodiments, the first property, the second property, or a combination thereof, are adjusted using a temperature of the fluid to account for temperature variations in the fluid.

[0009] In some embodiments, the system further includes a pump configured to pump water through the first conduit, into the microfluidic enclosure, and through the second conduit.

[0010] In some embodiments, the system further includes a water purification system configured to provide a purified water for a dialysis system, and the inlet sensor, the microfluidic enclosure, and the outlet sensor are configured to determine a total organic carbon in water output from the water purification system.

[0011] In some embodiments, the second conduit is fluidly connected to a drain to drain the fluid.

[0012] In some embodiments, the inlet sensor is configured to sense one or more properties of the fluid flowing through the first conduit, and the outlet sensor is configured to sense one or more other properties of the fluid flowing through the second conduit.Attorney Docket No. 218079.023801 (IDF00022)

[0013] In some embodiments, the inlet sensor is further configured to sense a third property of the fluid flowing through the first conduit, and the outlet is further configured to sense a fourth property of the fluid flowing through the second conduit.

[0014] In some embodiments, the inlet sensor further includes a first pH sensor and the outlet sensor further includes a second pH sensor, and the controller is further configured to receive the third property sensed by the first pH sensor, and receive the fourth property sensed by the second pH sensor, the controller determines the TOC within the fluid using a difference between the third property as sensed by the first pH sensor and the fourth property as sensed by the second pH sensor.

[0015] In some embodiments, the third property and the fourth property can be adjusted using another property such as, but not limited to, temperature.

[0016] In some embodiments, the inlet sensor is further configured to sense a fifth property of the fluid flowing through the first conduit, and the outlet is further configured to sense a sixth property of the fluid flowing through the second conduit.

[0017] In some embodiments, the inlet sensor further includes a first temperature sensor and the outlet sensor further includes a second temperature sensor, and the controller is further configured to receive the fifth property sensed by the first temperature sensor, and receive the sixth property sensed by the second temperature sensor, and the controller determines the TOC within the fluid using a difference between the first property as sensed and adjusted using the fifth property as sensed by the first temperature sensor and the second property as sensed and adjusted using the sixth property as sensed by the second temperature sensor.

[0018] In some embodiments, the microfluidic enclosure includes at least one sensor, the at least one sensor being configured to sense an amount of ultraviolet radiation emitted by the ultraviolet source.

[0019] In some embodiments, the controller is further configured to receive a first ultraviolet measurement from the at least one ultraviolet sensor corresponding to the amount of ultraviolet radiation emitted by the ultraviolet source, wherein theAttorney Docket No. 218079.023801 (IDF00022)controller determines a lifespan of the ultraviolet source using the first ultraviolet measurement.

[0020] In some embodiments, the at least one sensor is an infrared sensor.

[0021] In some embodiments, the microfluidic sample cell further includes a catalyzer substrate coating an interior surface of the microfluidic sample cell, the catalyzer substrate being configured to accelerate oxidation of the fluid in the microfluidic enclosure.

[0022] In some embodiments, the catalyzer substrate further includes a micro-pattern configured to contact the fluid to increase a mixing level of unoxidized species in the fluid in the microfluidic sample cell.

[0023] In some embodiments, a system including a plurality of first conduits, a plurality of inlet sensors configured to sense a first property of a fluid flowing through a respective one of the plurality of first conduits, a microfluidic enclosure fluidly connected to the plurality of first conduits, the microfluidic enclosure is disposed fluidly downstream of the plurality of inlet sensors, the microfluidic enclosure includes a housing having a plurality of inlets and a plurality of outlets, a plurality of microfluidic sample cells disposed within the housing, the plurality of microfluidic sample cells are at least partially transparent to ultraviolet radiation, the plurality of inlets are fluidly connected to respective ones of the plurality of first conduits, and an ultraviolet source disposed within the housing and configured to output ultraviolet radiation, a plurality of second conduits fluidly connected to the plurality of outlets, and a plurality of outlet sensors configured to sense a second property of the fluid as received from the microfluidic enclosure and disposed downstream of the microfluidic enclosure.

[0024] In some embodiments, the plurality of inlet sensors are conductivity sensors, and the plurality of outlet sensors are conductivity sensors.

[0025] In some embodiments, the system further includes a controller, the controller being configured to receive the first property, the first property being a first conductivity, receive the second property, the second property being a second conductivity, and determine a total organic carbon within the fluid using a difference between the first property and the second property.Attorney Docket No. 218079.023801 (IDF00022)

[0026] In some embodiments, the controller is configured to determine the TOC within the fluid using the first property as sensed and adjusted using another property such as, but not limited to, temperature, and the second property as sensed and adjusted using another property such as, but not limited to, temperature.

[0027] In some embodiments, the system further includes a pump configured to pump water through the plurality of first conduits, into the microfluidic enclosure, and through the plurality of second conduits.

[0028] In some embodiments, the system further includes a water purification system configured to provide a purified water for a dialysis system, and the plurality of inlet sensors, the microfluidic enclosure, and the plurality of outlet sensors are configured to determine a total organic carbon in water output from the water purification system.

[0029] In some embodiments, the total organic carbon is determined for a plurality of different locations in the water purification system.

[0030] In some embodiments, the plurality of second conduits is fluidly connected to a drain to drain the fluid.

[0031] In some embodiments, the system further includes a flow controller to fluidly connect one or more of the plurality of first conduits for initiating a fluid test.

[0032] In some embodiments, a dialysis system includes a water purification system configured to purify water for use in dialysis, and a total organic carbon sensing system including a first conduit, an inlet sensor configured to sense a first property of the water flowing through the first conduit, a microfluidic enclosure fluidly connected to the first conduit, the microfluidic enclosure is disposed fluidly downstream of the inlet sensor, the microfluidic enclosure includes a housing having an inlet and an outlet, a microfluidic sample cell disposed within the housing, the microfluidic sample cell is at least partially transparent to ultraviolet radiation, the inlet is fluidly connected to the first conduit, and an ultraviolet source disposed within the housing and configured to output ultraviolet radiation, a second conduit fluidly connected to the outlet, and an outlet sensor configured to sense a second property of the water as received from the microfluidic enclosure and disposed downstream of the microfluidic enclosure.Attorney Docket No. 218079.023801 (IDF00022)

[0033] In some embodiments, the inlet sensor is a first conductivity sensor and the outlet sensor is a second conductivity sensor.

[0034] In some embodiments, the dialysis system further includes a controller, the controller being configured to receive the first property, the first property being a first conductivity, receive the second property, the second property being a second conductivity, and determine a total organic carbon within the water using a difference between the first property and the second property.

[0035] In some embodiments, the controller is configured to determine the TOC within the fluid using the first property as sensed and adjusted using another property such as, but not limited to, temperature, and the second property as sensed and adjusted using another property such as, but not limited to, temperature.

[0036] In some embodiments, the controller is configured to enable the ultraviolet source to oxidize organic compounds within the water.

[0037] In some embodiments, the dialysis system further includes a pump configured to pump water through the first conduit, into the microfluidic enclosure, and through the second conduit.

[0038] In some embodiments, the second conduit is fluidly connected to a drain to drain the water.BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Some embodiments of the disclosure are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the embodiments shown are by way of example and for purposes of illustrative discussion of embodiments of the disclosure. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the disclosure may be practiced.

[0040] FIG. 1 is a schematic diagram of a dialysis system, according to some embodiments.

[0041] FIG. 2 is a schematic diagram of a TOC measurement system, according to some embodiments.Attorney Docket No. 218079.023801 (IDF00022)

[0042] FIG. 3 is a schematic diagram of the TOC measurement system, according to some embodiments.

[0043] FIG. 4 is a schematic diagram of the TOC measurement system, according to some embodiments.

[0044] FIG. 5 is a top view of a portion of the TOC measurement system, according to some embodiments.

[0045] FIG. 6 is a top view of the portion of the TOC measurement system, according to some embodiments.

[0046] FIG. 7 is a top view of the portion of the TOC measurement system, according to some embodiments.

[0047] FIG. 8 is a front view of the portion of the TOC measurement system, according to some embodiments.

[0048] FIG. 9 is a front view of the portion of the TOC measurement system, according to some embodiments.DETAILED DESCRIPTION

[0049] Peritoneal dialysis systems can include, for example, home therapy devices that provide persons needing dialysis therapy with greater flexibility in therapy options.

[0050] Various embodiments of the present disclosure relate to systems, devices, apparatuses, and methods for a Total Organic Carbon (“TOC”) measurement system. Total Organic Carbon (“TOC”) is a measure of the amount of carbon in a fluid such as, for example, water used to make dialysis fluids for peritoneal dialysis therapy. Prior to purification, the fluid can include therein impurities including, for example, organic compounds and other contaminants. The suitability of the fluid is determined by measuring the TOC, which is indicative of the concentration of organic compounds in the fluid, and then comparing the TOC to a threshold. The TOC measurement system can be implemented in a peritoneal dialysis system. The TOC measurement system can also be implemented in a hemodialysis system. In some embodiments, the peritoneal dialysis system or the hemodialysis system can be a home therapy device. In some embodiments, the peritoneal dialysis system can include one or more subsystems including the TOC measurementAttorney Docket No. 218079.023801 (IDF00022)system for purifying water obtained from a source into purified water, which can then be used to produce the dialysis fluid for therapy.

[0051] The TOC measurement system can process and analyze a fluid or a volume of fluid to determine the TOC of the fluid. The TOC is measured as a function of carbon dioxide (CO2) present in the fluid after undergoing oxidation of organic compounds present in the fluid. The carbon dioxide is produced by exposing the fluid to one or more different wavelengths of ultraviolet (UV) radiation to oxidize the organic compounds and to kill bacteria present in the fluid. The TOC of the fluid exceeding a threshold value may be indicative of contamination from, for example, microbiological contaminants or issues with the sterilization, purification, filtration, other subprocesses, or any combinations thereof. For example, the TOC of water used in making the dialysis fluid exceeding the threshold of 500 ppb can be indicative of biofilm present in the fluid of the system.

[0052] The TOC measurement system can be implemented inline to one or more other subsystems including, for example, a water purification system for purifying and filtering water used to make dialysis fluid for peritoneal dialysis therapy. The TOC measurement system can also be implemented, for example, inline to a water for injection (“WFI”) system used to produce purified water used in making dialysis fluid. In some embodiments, the TOC measurement system can be in a peritoneal dialysis system including therein one or more subsystems including the water filtration system, WFI system, other subsystems, or any combinations thereof. For example, the peritoneal dialysis system can be a home therapy device that processes potable water into purified water for use in producing the dialysis fluid.

[0053] In a non-limiting example, the TOC measurement system includes a first conduit, an inlet sensor located on the first conduit, a microfluidic enclosure, a second conduit, and an outlet sensor located on the second conduit, the microfluidic enclosure being in fluid communication with the first conduit and the second conduit. The microfluidic enclosure can include a housing having an inlet connected to the first conduit and an outlet connected to the second conduit, a microfluidic sample cell in fluid communication with the inlet and the outlet (and the first conduit and the second conduit), and a UV light source located in the housingAttorney Docket No. 218079.023801 (IDF00022)configured to output UV radiation to the microfluidic sample cell and the fluid therein.

[0054] In the microfluidic enclosure, the microfluidic sample cell can be a microchannel or a microchamber. In some embodiments, the microchannel can have a crosssection characteristic length of less than 1 mm. In some embodiments, the crosssection characteristic length can be from 1 pm to 500 pm, or any range or subrange therebetween. The microchamber is a chamber configured to hold the fluid in the microfluidic sample cell for performing the oxidation process. The microchamber can have a cross-section characteristic length of less than 1 mm. In some embodiments, the cross-section characteristic length can be from 1 pm to 500 pm, or any range or subrange therebetween. In some embodiments, the cross-section characteristic length can be from 1 pm to 99 pm, or any range or subrange therebetween In some embodiments, the microchannels in a given microfluidic enclosure can have a smaller cross-section characteristic length than the microchambers in the microfluidic enclosure. In some embodiments, the crosssection characteristic length can be a channel height.

[0055] It is to be appreciated that the size of the microchannels and microchambers for the microfluidic sample cells are not intended to be limiting, and they can have different sizes, dimensions, and inner diameters to accommodate different volumes of fluid depending on factors such as, for example, the application, sampling volume, sampling time, sampling rate, oxidation parameters, measurement parameters, available dimensions for the TOC measurement system, or one or more portions thereof, other like factors, or any combinations thereof.

[0056] Depending on the configuration, the microfluidic sample cell can include one or more branches and the microfluidic sample cell can be connected to one or more inlets and one or more outlets. For example, the microfluidic sample cell can be a microchannel connected to a single inlet and connected to two outlets via a branching microchannel, the single inlet in fluid communication with a first conduit and inlet sensor and each of the outlets in fluid communication with a respectiveAttorney Docket No. 218079.023801 (IDF00022)second conduit and respective outlet sensor. In some embodiments, the microfluidic sample cell can be straight or can include therein one or more curves.

[0057] The microfluidic enclosure, or one or more portions thereof, can be made of materials including microfabricated quartz or synthetic silica. In some embodiments, the one or more portions of the microfluidic enclosure can be made of fused quarts or fused synthetic silica. In some embodiments, the one or more portions of the microfluidic enclosure that are made of the microfabricated quartz or synthetic silica can include, but is not limited to, the housing, inlet, outlet, microfluidic sample cell, or any combinations thereof. In some embodiments, the microfluidic sample cell can be made of microfabricated quartz or synthetic silica. The microfluidic sample cell is made of the microfabricated quartz or synthetic silica to enable the microfluidic sample cell to be at least partially transparent. In some embodiments, the materials used to form the microfluidic sample cell are configured to enable certain wavelengths of UV light emitted from a UV light source to pass through the microfluidic sample cell wall and be applied onto the fluid therein, thereby allowing the oxidation process in the microfluidic sample cell.

[0058] The microfluidic enclosure, or one or more portions thereof, can include a catalyzer substrate applied onto one or more surfaces. The catalyst substrate can accelerate the photo-oxidation of the organic compounds in the fluid. In some embodiments, the catalyzer substrate can coat an inner surface of the microfluidic sample cell. In other embodiments, the catalyzer substrate can coat one or more inner surfaces of the microfluidic sample cell. In some embodiments, the catalyzer substrate can be applied onto an interior surface of the microfluidic enclosure, and the microfluidic sample cell can be formed so that the catalyzer substrate forms an inner surface of the channel of the microfluidic sample cell. The catalyst substrate can further include a micro-structure having a certain pattern, the pattern being configured to contact the fluid and thereby increase the mixing level of unoxidized compound species within the fluid in the microchannel. In some embodiments, the micro-structure can be a plurality of ribs. In some embodiments, the plurality of ribs can have a V-shaped pattern.Attorney Docket No. 218079.023801 (IDF00022)

[0059] The TOC measurement system may include one or more pumps (e.g., micropumps) and one or more valves (e.g., microvalves) that can be operated to regulate the flow of fluid for testing from one or more subsystems including, but not limited to, TOC measurement system, water filtration system, WFI system, other external subsystems of a peritoneal dialysis system associated with the TOC measurement system, or any combinations thereof. The TOC measurement system can operate the pumps and valves to direct a small volume of the fluid to one or more components of the TOC measurement system including the inlet sensor, the microfluidic enclosure, and the outlet sensor for measurement. The inlet sensor measures the first property of the small volume of fluid prior to the fluid passing into the microfluidic enclosure, the microfluidic enclosure and the UV light source perform the oxidation process on the small volume of fluid in the microfluidic sample cell, and the outlet sensor measures the second property of the small volume of fluid received from the microfluidic enclosure.

[0060] The TOC measurement system is configured to measure and oxidize small volumes of fluid. In some embodiments, as used herein, “small volumes of fluid” refers to fluids in a range of 10 nanoliters (nL) to 10 milliliters (mL). It is to be appreciated that the exact volume of fluid can vary. By using small volumes of fluid in the microfluidic enclosure of the TOC measurement system, the volume of fluid can complete oxidation in relatively shorter periods of time. Organic compounds are not directly oxidized down to carbon dioxide, but intermediate oxidation products like organic acids may be created that contribute to water conductivity and the pH of the fluid. Therefore, different combinations of TOC and flow rates can result in the same or similar electrical conductivity measurements and pH measurements in cases of incomplete oxidation, thereby preventing accurate correlations from being established when working with different flow rates.

[0061] In another non-limiting example, the TOC measurement system can include a plurality of first conduits, a plurality of inlet sensors, a microfluidic enclosure including therein a plurality of microfluidic sample cells and at least one UV energy source, a plurality of second conduits, and a plurality of outlet sensors. Each microfluidic sample cell can be in fluid communication with one or more respectiveAttorney Docket No. 218079.023801 (IDF00022)first conduits and one or more respective second conduits, and the corresponding inlet sensors and outlet sensors located at the respective first conduits and second conduits.

[0062] The contribution of organic compounds to electrical conductivity can be negligible in the fluid. Moreover, although the contribution of carbon dioxide to electrical conductivity can also be low, it is still relatively higher than compared with organic compounds. The embodiments described in the present disclosure performs photo-oxidation of fluid in the microfluidic sample cell of the microfluidic enclosure by exposing the fluid to certain wavelengths of UV radiation to cause the organic compounds in the fluid to produce carbon dioxide. The effects of the photooxidation corresponding to the TOC can be determined using the inlet sensor and the outlet sensor, the TOC being a function of the carbon dioxide present in the fluid after undergoing oxidation. The fluid in the microfluidic sample cell can be exposed to UV radiation having a first reference peak wavelength and a second reference peak wavelength, according to some embodiments. The first reference peak wavelength can be used to oxidize chemical compounds present in the fluid and the second reference peak wavelength can be used to kill bacteria present in the fluid and the organic residual from killed bacteria oxidized by the first reference peak wavelength.

[0063] The inlet sensor can measure one or more properties of the fluid before it enters the microfluidic enclosure to determine a baseline TOC of the fluid, and the outlet sensor can measure the one or more properties the fluid exiting the microfluidic enclosure. Based on the properties sensed by the respective inlet sensor and outlet sensor, the TOC of the fluid resulting from exposing the fluid in the microfluidic enclosure to UV radiation can be determined. In some embodiments, the system can include a controller configured to determine the TOC of the fluid based on the measurement of the one or more respective properties by the one or more sensors.

[0064] According to some embodiments, the inlet sensor and the outlet sensor can measure an electrical conductivity of the fluid. In some embodiments, the inlet sensor can include a first conductivity sensor for monitoring electrical conductivityAttorney Docket No. 218079.023801 (IDF00022)of the fluid at the inlet and the outlet sensor can include a second conductivity sensor for monitoring the electrical conductivity of the fluid at the outlet, and the TOC of the fluid can be determined based on the respective electrical conductivity measurements of the first conductivity sensor and the second conductivity sensor.

[0065] According to some embodiments, the inlet sensor and the outlet sensor can measure a pH of the fluid to enable determining intermediate oxidation products such as, for example, organic acids in the fluid. In some embodiments, the inlet sensor can include a pH sensor for monitoring a pH of the fluid at the inlet and the outlet sensor can include a second pH sensor for monitoring the pH of the fluid at the outlet, and the TOC of the fluid can be determined based on the respective pH level measurements of the first pH sensor and the second pH sensor.

[0066] According to some embodiments, the inlet sensor and the outlet sensor can measure a temperature of the fluid to compensate for temperature effects on the electrical conductivity, pH, UV, or any combinations thereof. In some embodiments, the inlet sensor can further include a first temperature sensor for monitoring a temperature of the fluid at the inlet and the outlet sensor can include a second temperature sensor for monitoring the temperature of the fluid at the outlet.. In some embodiments, the temperature sensors can be used to correlate conductivity to a reference temperature to account for changes in temperature because of the applied UV radiation. In some embodiments, the inlet sensor can include at least one of the first conductivity sensor, first pH sensor, and first temperature sensor; and the outlet sensor can include at least one of the second conductivity sensor, second pH sensor, and second temperature sensor. In other embodiments, the inlet sensor can include the first conductivity sensor, first pH sensor, first temperature sensor, or any combinations thereof; and the outlet sensor can include the second conductivity sensor, second pH sensor, second temperature sensor, or any combinations thereof.

[0067] According to some embodiments, the microfluidic enclosure can include a sensor.The sensor can monitor an amount of radiation that is absorbed by the carbon dioxide in the fluid in the microfluidic channels. In some embodiments, the sensor can include an infrared (IR) emitter and an IR receiver. In response to applying theAttorney Docket No. 218079.023801 (IDF00022)UV radiation from the UV light source to the fluid in the microfluidic sample cell, carbon dioxide molecules in the fluid can absorb a certain amount of the UV radiation energy emitted by the UV light source corresponding to the vibrational frequency of the carbon dioxide molecule multiplied by Planck’s constant. The difference between the amount of radiation emitted by the UV light source and the amount of radiation measured by the sensor after having passed through the fluid in the microfluidic channels can be an index representative of the amount of carbon dioxide produced by oxidation.

[0068] In some embodiments, the microfluidic enclosure can include a UV sensor. The UV sensor can be located opposite the microfluidic channel from the energy source to measure the radiation emitted by the energy source after having passed through the fluid.. The UV sensor can monitor an amount of radiation emitted by the energy source. That is, the microfluidic enclosure can include a UV sensor to determine whether the UV energy source is working properly or beginning to fail.

[0069] The TOC measurement systems provide one or more improvements over other systems and methodologies for TOC measurement including, for example, the microfluidic enclosure utilizes microchambers and microchannels for smaller volumes of fluid fortesting, thereby improving the photo-oxidation of the fluid. That is, by utilizing smaller sample volumes, relatively lower flow rates can be utilized for complete oxidation of the organic compounds in the fluid to facilitate correlating the amount of carbon dioxide to TOC even when flow rates may need adjusting for different volume samples. Furthermore, the smaller volumes necessitate less radiation to complete oxidation, allowing for use of energy sources that have lower electrical power demands and that can operate at lower surface temperatures compared with conventional TOC measurement systems. In addition, the smaller volumes of fluid for testing decreases the amount of waste fluid that is generated during testing.

[0070] In addition, the sensors utilized in the TOC measurement system have a smaller form factor as compared with other known systems. The smaller size of the sensors, combined with using microfluidics, enables the TOC measurement system to have a smaller overall size compared with other known systems, andAttorney Docket No. 218079.023801 (IDF00022)the TOC management system therefore has higher versatility in implementation and design. The TOC measurement system is capable of measuring different parameters including conductivity, pH, temperature, and IR absorption, depending on application. In addition, the system can regulate flow throughout the system, and can perform multiple and differential analysis of fluid from different subsystems, thereby providing improved versatility and improved adaptability to different testing parameters and system architectures and easing modification of the system to adapt to the different flows, volumes, and architectures.

[0071] Among those benefits and improvements that have been disclosed, other objects and advantages of this disclosure will become apparent from the following description taken in conjunction with the accompanying figures. Detailed embodiments of the present disclosure are disclosed herein; however, it is to be understood that the disclosed embodiments are merely illustrative of the disclosure that may be embodied in various forms. In addition, each of the examples given regarding the various embodiments of the disclosure which are intended to be illustrative, and not restrictive.

[0072] FIG. 1 is a schematic diagram of a dialysis system 100, according to some embodiments. In some embodiments, the dialysis system 100 can be representative of a peritoneal dialysis system including point of use dialysis fluid production. Peritoneal dialysis systems are one example of a dialysis system. It is to be appreciated that the systems and methods described in this disclosure can be applied to other dialysis systems such as, but not limited to, hemodialysis, hemofiltration, hemodiafiltration, or the like.

[0073] The illustrated embodiment includes a water purification system 102. A controller 104 is configured to be in electronic communication with the water purification system 102 to send and receive communications relating to sensed parameters, control of valves, or the like. The water purification system 102 can be fluidly connected to a cycler 106. The cycler 106 can be fluidly connected with a patient to perform the dialysis treatments. The cycler 106 can be configured to inject the dialysis fluid into the patient and drain the dialysis fluid when the treatment isAttorney Docket No. 218079.023801 (IDF00022)complete. The cycler 106 can be in electronic communication with the controller 104 to accomplish the necessary treatments for the patient.

[0074] The water purification system 102 includes a Total Organic Carbon (“TOC”) measurement system 112. The TOC measurement system 112 is configured to determine a TOC concentration of a fluid in the water purification system 102. The water purification system 102 may utilize the TOC measurement system to prepare the purified water, prepare the fresh dialysis fluid using the purified water, at other points in the water purification system 102, or any combinations thereof. In some embodiments, another device in the water purification system 102 may prepare the fresh dialysis fluid using purified water output from the water purification system 102. For example, the water purification system 102 may include a preparator for mixing the fresh dialysis fluid using purified water. The preparator can be in electronic communication with the controller 104 and the cycler 106 to accomplish the necessary treatments for the patient. In some embodiments, the preparator can be in electronic communication with the cycler 106 to accomplish the necessary treatments for the patient. In some embodiments, the TOC measurement system 112 can be located in one or more other systems of the water purification system 102 such as, for example, the preparator. It is to be appreciated that the cycler 106 can include one or more additional features such as, but not limited to, a user interface configured to receive user inputs, display outputs for the user, or any combination thereof.

[0075] The controller 104 can be in wired or wireless communication with the water purification system 102. In some embodiments, the controller 104 can be in wired or wireless communication with one or more modules in the water purification system 102 including, but not limited to, the TOC measurement system 112. The controller 104 can include a memory 108 and at least one processor 110. It is to be appreciated that the controller 104 can include one or more additional features such as, but not limited to, a display with a user interface configured to receive user inputs, display outputs for the user, or any combination thereof. In some embodiments, a separate user input can also be included so the user can interact with the dialysis system 100.Attorney Docket No. 218079.023801 (IDF00022)

[0076] FIG. 2 is a schematic diagram of a first non-limiting example of a TOC measurement system 112, according to some embodiments. The TOC measurement system 112 includes a first conduit 120, an inlet sensor 122, a microfluidic enclosure 124, a second conduit 126, and an outlet sensor 128.

[0077] First conduit 120 is in fluid connection with an inlet 136 of the microfluidic enclosure 124 and the second conduit 126 is in fluid connection with an outlet 138 of the microfluidic enclosure 124.

[0078] Inlet sensor 122 is located at first conduit 120. The inlet sensor 122 is configured to sense a first property of a fluid flowing through the first conduit 120. In some embodiments, the inlet sensor 122 is a first conductivity sensor. In some embodiments, the inlet sensor 122, or one or more portions thereof, can be in physical contact with the fluid in the first conduit 120. In other embodiments, the inlet sensor 122 can be isolated from the fluid in the first conduit 120 and the inlet sensor 122 is configured to measure the first property without coming into contact with the fluid. In some embodiments, the inlet sensor 122 can be a conductivity sensor, a temperature sensor, a pH sensor, combinations thereof, or the like.

[0079] Microfluidic enclosure 124 is fluidly connected to the first conduit 120 and the second conduit 126. The microfluidic enclosure 124 is disposed fluidly downstream of the inlet sensor 122. The microfluidic enclosure 124 includes a housing 130, a microfluidic sample cell 132 disposed within the housing 130, and an energy source 134 disposed within the housing 130. The housing 130 has the inlet 136 and the outlet 138. In some embodiments, the inlet 136 is fluidly connected to the first conduit 120. In some embodiments, the outlet 138 is fluidly connected to the second conduit 126. The microfluidic enclosure 124 may also be referred to as a microfluidic chip, oxidation chip, and the like.

[0080] The microfluidic sample cell 132 can be a microchannel or microchamber in fluid connection with the inlet 136 and the outlet 138 of the housing 130. In some embodiments, the microfluidic sample cell 132 can be in fluid connection with the first conduit 120 and the second conduit 126 at a respective inlet 136 and outlet 138. The microfluidic sample cell 132 can also be referred to as a microchamber, according to some embodiments. In some embodiments, the microfluidic sampleAttorney Docket No. 218079.023801 (IDF00022)cell 132 can be a straight conduit connected to a single inlet 136 and outlet 138. In other embodiments, the microfluidic sample cell 132 can include one or more branches and can be connected to a single inlet 136, a plurality of inlets 136, a single outlet 138, a plurality of outlets 138, or any combinations thereof.

[0081] The microfluidic sample cell 132 can be a microchannel. The microchannel can have a cross-section characteristic length of up to 500 pm . In some embodiments, the cross-section characteristic length can be a channel height.

[0082] The energy source 134 is a UV light source configured to output radiation in the form of ultraviolet (“UV”) radiation to oxidize carbon dioxide from the organic compounds in the fluid in the microfluidic sample cell 132. The microfluidic enclosure 124 can include a single energy source 134. In some embodiments, the UV light emitted by the single energy source 134 can be capable of covering the entire interior region of the housing 130 and can thereby be applied to each microfluidic sample cell 132 therein. In other embodiments, the microfluidic enclosure 124 can include an array including a plurality of the energy source 134 arranged so as to cover the entire interior region of the microfluidic enclosure 124.

[0083] The energy source 134 is configured to output UV radiation at one or more peak reference wavelengths. In some embodiments, the energy source 134 is configured to output UV radiation at a first peak reference wavelength and a second peak reference wavelength. In some embodiments, the first peak reference wavelength is at 185 nm. In other embodiments, the first peak reference wavelength is at approximately 185 nm. In some embodiments, the second peak reference wavelength is at 254 nm. In other embodiments, the second peak reference wavelength is at approximately 254 nm. In some embodiments, the radiation emitted by the energy source 134 can be in a range between 100 nm to 400 nm, or any range or subrange therebetween.

[0084] In some embodiments, the energy source 134 can emit radiation in the range of 100 nm to 400 nm, 150 nm to 400 nm, 200 nm to 400 nm, 250 nm to 400 nm, 300 nm to 400 nm, 350 nm to 400 nm, 100 nm to 350 nm, 150 nm to 350 nm, 200 nm to 350 nm, 250 nm to 350 nm, 300 nm to 350 nm, 100 nm to 300 nm, 150 nm to 300 nm, 200 nm to 300 nm, 250 nm to 300 nm, 100 nm to 250 nm, 150 nm to 250Attorney Docket No. 218079.023801 (IDF00022)nm, 200 nm to 250 nm, 100 nm to 200 nm, 150 nm to 200 nm, 100 nm to 150 nm, other ranges, or any combinations thereof. It is to be appreciated that the energy source 134 can output UV radiation at one or more wavelengths in accordance with the present disclosure to cause oxidation of the organic compounds in the fluid to enable measurement of the carbon dioxide in the fluid.

[0085] In some embodiments, the microfluidic sample cell 132 is made of a suitable material to be at least partially transparent to radiation so as to enable exposing the fluid in the microfluidic sample cell 132 to the radiation emitted by the energy source 134 through the sidewall of the microfluidic sample cell 132. The microfluidic sample cell 132 can be made of quartz. In some embodiments, the microfluidic sample cell 132 can be fully made of quartz. In some embodiments, the microfluidic sample cell 132 can be made of fused quartz. In other embodiments, the microfluidic sample cell 132 can be fully made of fused quartz. In some embodiments, the microfluidic sample cell 132 can be made of fused synthetic silica. In other embodiments, the microfluidic sample cell 132 can be fully made ef fused synthetic silica.

[0086] Second conduit 126 is fluidly connected to the outlet 138 of housing 130 of the microfluidic enclosure 124. In some embodiments, the second conduit 126 is also fluidly connected to a drain to drain the fluid after measuring the TOC of the fluid.

[0087] Outlet sensor 128 is located at second conduit 126 disposed downstream of the microfluidic enclosure 124. The outlet sensor 128 is configured to sense a second property of the fluid as received from the microfluidic enclosure 124. In some embodiments, the outlet sensor 128 is a second conductivity sensor. In some embodiments, the outlet sensor 128, or one or more portions thereof, can be in physical contact with the fluid in the first conduit 120. In other embodiments, the outlet sensor 128 can be isolated from the fluid in the second conduit 126 and the outlet sensor 128 is configured to measure the second property without coming into contact with the fluid. In some embodiments, the outlet sensor 128 can be a conductivity sensor, a temperature sensor, a pH sensor, combinations thereof, or the like. In some embodiments, the outlet sensor 128 can be an IR sensor including both an IR emitter and an IR receiver. In such embodiments, an amount of the IRAttorney Docket No. 218079.023801 (IDF00022)signal from the emitter absorbed by the fluid can be determinative of a TOC measurement of the fluid. It is to be appreciated that in such embodiments, the inlet sensor 122 should also include an IR sensor.

[0088] To measure the TOC in the fluid, the inlet sensor 122 located at first conduit 120 can measure the first property of the fluid as it passes through the first conduit 120 and to the microfluidic enclosure 124, the energy source 134 can emit radiation onto the volume of fluid in the microfluidic sample cell 132 at microfluidic enclosure 124 to cause the organic compounds in the fluid to oxidize into carbon dioxide, and the outlet sensor 128 at the second conduit 126 can measure the second property of the fluid as it passes from the microfluidic enclosure 124 and through the second conduit 126.

[0089] In some embodiments, the TOC measurement system 112 further includes a controller 140. In some embodiments, the controller 140 is configured to receive the first property, receive the second property, and determine a total organic carbon within the fluid using a difference between the first property as sensed and the second property as sensed. It is to be appreciated that in some embodiments, the controller 140 is configured to compensate the as sensed values according to another parameter such as, but not limited to, temperature or the like. In some embodiments, the use of temperature can compensate for the changes in temperature which can affect the first property and the second property. In some embodiments, the first property is the first conductivity measured by the inlet sensor 122, the second property is the second conductivity measured by the outlet sensor 128, and the TOC can be determined within the fluid using a difference between the first property as sensed using the inlet sensor 122 and the second property as sensed using the outlet sensor 128.

[0090] In some embodiments, the TOC measurement system 112 further includes a pump 142. The pump 142 is configured to pump water through the first conduit 120, into the microfluidic enclosure 124, and through the second conduit 126. By flowing through the first conduit 120 and the second conduit 126, respectively, the fluid also flows through the inlet sensor 122 and the outlet sensor 128 for measuringAttorney Docket No. 218079.023801 (IDF00022)the first property and the second property, respectively. In some embodiments, the pump 142 can be a micropump.

[0091] In some embodiments, the TOC measurement system 112 can be disposed within a water purification system. The water purification system is configured to provide a purified water for a dialysis system, and the inlet sensor, the microfluidic enclosure, and the outlet sensor are configured to determine a TOC level in water output from the water purification system. In some embodiments, the water purification system can be water purification system 102 as shown in FIG. 1.

[0092] FIG. 3 is a schematic diagram of a second non-limiting example of the TOC measurement system 112, according to some embodiments.

[0093] According to some embodiments, in the TOC measurement system 112, the inlet sensor 122 and the outlet sensor 128 are configured to sense one or more properties of the fluid flowing through the first conduit 120 and the second conduit 126, respectively.

[0094] In some embodiments, the one or more properties includes a first property and a second property. The inlet sensor 122 is configured to sense the first property of the fluid and the outlet sensor 128 is configured to sense the second property of the fluid. In some embodiments, the first property is a first electrical conductivity, and the second property is a second electrical conductivity. In some embodiments, the inlet sensor 122 is a first conductivity sensor 144 configured to sense the first electrical conductivity of the fluid at the first conduit 120, and the outlet sensor 128 is a second conductivity sensor 146 configured to sense the second electrical conductivity of the fluid flowing through the second conduit 126.

[0095] In some embodiments, the one or more properties includes a third property and a fourth property. The inlet sensor 122 is configured to sense the third property of the fluid and the outlet sensor 128 is configured to sense the fourth property of the fluid. In some embodiments, the third property is a first pH, and the fourth property is a second pH, and the inlet sensor 122 is a first pH sensor 148 configured to sense the first pH of the fluid at the first conduit 120, and the outlet sensor 128 is a second pH sensor 150 configured to sense the second pH of the fluid flowing through the second conduit 126.Attorney Docket No. 218079.023801 (IDF00022)

[0096] In some embodiments, the one or more properties includes a fifth property and a sixth property. The inlet sensor 122 is configured to sense the fifth property of the fluid and the outlet sensor 128 is configured to sense the sixth property of the fluid. In some embodiments, the fifth property is a first temperature, and the sixth property is a second temperature, and the inlet sensor 122 is a first temperature probe 152 configured to sense the first temperature of the fluid at the first conduit 120, and the outlet sensor 128 is a second temperature probe 154 configured to sense a second temperature of the fluid flowing through the second conduit 126.

[0097] The inlet sensor 122 can include the first conductivity sensor 144, first pH sensor 148, first temperature probe 152, or any combinations thereof. The microfluidic enclosure 124 can include the second conductivity sensor 146, second pH sensor 150, second temperature probe 154, or any combinations thereof. In some embodiments, the inlet sensor 122 can include the first conductivity sensor 144 and the first pH sensor 148, and the outlet sensor 128 can include the second conductivity sensor 146 and the second pH sensor. In other embodiments, the inlet sensor 122 can include the first conductivity sensor 144 and the first temperature probe 152, and the outlet sensor 128 can include the second conductivity sensor 146 and the second temperature probe 154. In yet other embodiments, the inlet sensor 122 can include the first pH sensor 148 and the first temperature probe 152, and the outlet sensor 128 can include the second pH sensor 150 and the second temperature probe 154.

[0098] In some embodiments, the inlet sensor 122 can be an IR sensor. In such embodiments, the inlet sensor 122 can include an IR emitter and an IR receiver. The inlet sensor 122 can determine an amount of IR radiation that passes through the fluid and is not absorbed by the fluid.

[0099] In some embodiments, the outlet sensor 128 can be an IR sensor. In such embodiments, the outlet sensor 128 can include an IR emitter and an IR receiver. The outlet sensor 128 can determine an amount of IR radiation that passes through the fluid and is not absorbed by the fluid.

[0100] In some embodiments, the controller 140 is further configured to receive a first IR measurement at the inlet sensor 122 and a second IR measurement at the outletAttorney Docket No. 218079.023801 (IDF00022)sensor 128 corresponding to an amount of radiation absorbed by the fluid, and the controller determines the TOC within the fluid using, at least in part, a difference between the first IR measurement and the second IR measurement.

[0101] In some embodiments, the inlet sensor 122 can be a UV sensor. In such embodiments, the inlet sensor 122 can include a UV emitter and a UV receiver. In such embodiments, the inlet sensor 122 can determine an amount of UV radiation that passes through the fluid (e.g., from the emitter and received by the receiver) and is not absorbed by the fluid.

[0102] In some embodiments, the outlet sensor 128 can be a UV sensor. In such embodiments, the outlet sensor 128 can include a UV emitter and a UV receiver. In such embodiments, the outlet sensor 128 can determine an amount of UV radiation that passes through the fluid (e.g., from the emitter and received by the receiver) and is not absorbed by the fluid.

[0103] In some embodiments, the controller 140 is further configured to receive a first UV measurement at the inlet sensor 122 and a second UV measurement at the outlet sensor 128 corresponding to an amount of radiation absorbed by the fluid, and the controller determines the TOC within the fluid using, at least in part, a difference between the first UV measurement and the second UV measurement.

[0104] The TOC measurement system 112 can include the controller 140. The controller 140 can perform operations including receiving the first property, receiving the second property, and determining a TOC within the fluid using a difference between the first property as sensed and the second property as sensed. As used herein, using the first property as sensed and the second property as sensed can also include compensating the as-sensed values based on another parameter that can cause variability in the sensing such as, but not limited to, temperature. In some embodiments, the first property is a first conductivity sensed by the first conductivity sensor 144, the second property is a second conductivity sensed by the second conductivity sensor 146, and the TOC is determined using the difference between the first conductivity and the second conductivity.

[0105] In some embodiments, the controller 140 can perform operations including receive the third property, receive the fourth property, and determine a TOC within the fluidAttorney Docket No. 218079.023801 (IDF00022)using a difference between the third property as sensed and the fourth property as sensed. In some embodiments, the third property is a first pH sensed by the first pH sensor 148, the fourth property is a second pH sensed by the second pH sensor 150, and the TOC is determined using the difference between the first pH and the second pH.

[0106] In some embodiments, the controller 140 can perform operations including receive the fifth property, receive the sixth property, and determine a TOC within the fluid using a difference between the first property as adjusted using the fifth property as sensed and the second property as adjusted using the sixth property as sensed. In some embodiments, the fifth property is a first temperature sensed by the first temperature probe 152, the sixth property is a second temperature sensed by the second temperature probe 154, and the TOC is determined using the difference between the first property as adjusted using the first temperature and the second property as adjusted using the second temperature. It is to be appreciated that the temperature can be used to adjust the other properties (e.g., third and fourth) not just the first and second properties.

[0107] In some embodiments, the controller 140 can perform operations including, but not limited to, receive the first property from first conductivity sensor 144, receive the second property from second conductivity sensor 146, receive the third property from first pH sensor 148, receive the fourth property from second pH sensor 150, receive the fifth property from first temperature probe 152, receive the sixth property from second temperature probe 154, receive one or more other properties from one or more other sensors, or any combinations thereof. In some embodiments, the controller 140 can further perform operations including determine the TOC using the differences between the first property, second property, third property, fourth property, fifth property, sixth property, one or more other properties, or any combinations thereof.

[0108] In the TOC measurement system 112, the microfluidic enclosure 124 can include at least one sensor 156. In some embodiments, the at least one sensor 156 can be an ultraviolet sensor. The at least one sensor 156 can be located in the housing 130 opposite the microfluidic sample cell 132 from the energy source 134. The atAttorney Docket No. 218079.023801 (IDF00022)least one sensor 156 can be configured to sense an amount of radiation emitted by the energy source 134. In this regard, the radiation sensed by the at least one ultraviolet sensor 156 can be used to determine whether the energy source 134 is functioning properly.

[0109] FIG. 4 is a schematic diagram of another non-limiting example of the TOC measurement system 112, according to some embodiments.

[0110] The TOC measurement system 112 can include a plurality of first conduits 120, a plurality of inlet sensors 122 configured to sense a first property of a fluid flowing through a respective one of the plurality of first conduits 120, a microfluidic enclosure 124 fluidly connected to the plurality of first conduits 120, the microfluidic enclosure 124 being disposed fluidly downstream of the plurality of inlet sensors 122, and the microfluidic enclosure 124 including a housing 130 having a plurality of inlets 136 and a plurality of outlets 138, a plurality of microfluidic sample cells 132 disposed within the housing 130, the plurality of microfluidic sample cells 132 being at least partially transparent to LIV radiation, the plurality of inlets 136 being fluidly connected to respective ones of the plurality of first conduits 120, an energy source 134 being disposed within the housing 130 and configured to output ultraviolet radiation, and a plurality of second conduits 126 fluidly connected to the plurality of outlets 138; a plurality of outlet sensors 128 configured to sense a second property of the fluid as received from the microfluidic enclosure 124 and disposed downstream of the microfluidic enclosure 124.

[0111] In some embodiments, the TOC measurement system 112 includes an inlet array 160 and an outlet array 162. In some embodiments, the inlet array 160 can include the plurality of the inlet sensors 122 and the outlet array 162 can include the plurality of the outlet sensors 128. In some embodiments, the plurality of inlet sensors 122 are a plurality of first conductivity sensors and the plurality of outlet sensors 128 are a plurality of conductivity sensors, and the controller 140 is configured to receive the first property, the first property including a respective first conductivity from the plurality of first conductivity sensors, receive the second property, the second property including a respective second conductivity from theAttorney Docket No. 218079.023801 (IDF00022)plurality of second conductivity sensors, and determine a TOC within the fluid using a difference between the first property and the second property.

[0112] The inlet sensor 122 can include a plurality of sensors therein. In some embodiments, the plurality of sensors in the inlet sensor 122 can include, but is not limited to, a plurality of the first conductivity sensors, a plurality of first pH sensors, a plurality of first temperature probes, or any combinations thereof. The outlet sensor 128 can also include a plurality of sensors therein. In some embodiments, the plurality of sensors in the outlet sensor 128 can include, but is not limited to, a plurality of the second conductivity sensors, a plurality of second pH sensors, a plurality of second temperature probes, or any combinations thereof.

[0113] The microfluidic enclosure 124 includes a plurality of the microfluidic sample cells 132 and an energy source 134. Each microfluidic sample cell 132 of the plurality of the microfluidic sample cells 132 can be in fluid connection with a respective one of the plurality of the first conduits 120. The microfluidic enclosure 124 can also include the at least one sensor 156 (FIG. 3). In some embodiments, the microfluidic enclosure 124 can include a plurality of ultraviolet sensors located in the housing 130. In some embodiments, the at least one sensor 156 can be used to monitor a lifespan of the energy source 134 or that the energy source 134 is functioning properly.

[0114] In some embodiments, the inlet sensor 122 can be an IR sensor. In such embodiments, the inlet sensor 122 can include an IR emitter and an IR receiver. The inlet sensor 122 can determine an amount of IR radiation that passes through the fluid and is not absorbed by the fluid.

[0115] In some embodiments, the outlet sensor 128 can be an IR sensor. In such embodiments, the outlet sensor 128 can include an IR emitter and an IR receiver. The outlet sensor 128 can determine an amount of IR radiation that passes through the fluid and is not absorbed by the fluid.

[0116] In some embodiments, the controller 140 is further configured to receive a first IR measurement at the inlet sensor 122 and a second IR measurement at the outlet sensor 128 corresponding to an amount of radiation absorbed by the fluid, and theAttorney Docket No. 218079.023801 (IDF00022)controller determines the TOC within the fluid using, at least in part, a difference between the first IR measurement and the second IR measurement.

[0117] In some embodiments, the inlet sensor 122 can be a UV sensor. In such embodiments, the inlet sensor 122 can include a UV emitter and a UV receiver. In such embodiments, the inlet sensor 122 can determine an amount of UV radiation that passes through the fluid (e.g., from the emitter and received by the receiver) and is not absorbed by the fluid.

[0118] In some embodiments, the outlet sensor 128 can be a UV sensor. In such embodiments, the outlet sensor 128 can include a UV emitter and a UV receiver. In such embodiments, the outlet sensor 128 can determine an amount of UV radiation that passes through the fluid (e.g., from the emitter and received by the receiver) and is not absorbed by the fluid.

[0119] In some embodiments, the controller 140 is further configured to receive a first UV measurement at the inlet sensor 122 and a second UV measurement at the outlet sensor 128 corresponding to an amount of radiation absorbed by the fluid, and the controller determines the TOC within the fluid using, at least in part, a difference between the first UV measurement and the second UV measurement.

[0120] In some embodiments, the TOC measurement system 112 further includes a pump 142 configured to pump water through the plurality of first conduits 120, into the microfluidic enclosure 124, and through the plurality of second conduits 126. In some embodiments, the TOC measurement system 112 can be included in a water purification system such as, for example, water purification system 102 in FIG. 1, the water purification system 102 being configured to provide a purified water for a dialysis system. In some embodiments, the plurality of inlet sensors 122, the microfluidic enclosure 124, and the plurality of outlet sensors 128 are configured to determine a TOC in water output from the water purification system. In some embodiments, the TOC can be determined for a plurality of different locations in the water purification system. In some embodiments, each location of the plurality of different locations in the water purification system can correspond to one of the plurality of the first conduits 120. In the illustrated embodiment, the pump 142 is disposed on the outlet side, but can alternatively be placed on the inlet side.Attorney Docket No. 218079.023801 (IDF00022)

[0121] The TOC measurement system 112 can further include a flow controller 164 to fluidly connect one or more of the plurality of first conduits 120 for initiating a fluid test. In some embodiments, the flow controller 164 can fluidly connect one or more of the plurality of first conduits 120 to the pump 142 and to initiate the fluid test in the corresponding one of the plurality of first conduit 120 and plurality of second conduits 126. In some embodiments, the TOC measurement system 112 can further include one or more valves 166. Referring to FIG. 4, the one or more valves 166 is shown including a three-way microvalve connecting a plurality of the first conduits 120 to the flow controller 164 through a corresponding plurality of the microfluidic sample cells 132 in the microfluidic enclosure 124. In some embodiments, the plurality of second conduits 126 are fluidly connected to a drain to drain the fluid.

[0122] The TOC measurement system 112 can include the plurality of first conduits 120 and the plurality of second conduits 126, and the microfluidic enclosure 124 can include a plurality of microfluidic sample cells 132 therein, thereby forming a multichannel system to perform a differential analysis on the TOC at one or more different parts of the TOC measurement system 112 such as, for example, throughout water purification system 102 in FIG. 1. The TOC measurement system 112 can be managed by a system of micropumps such as pump 142 and one or more microvalves such as valve 166 and flow controller 164 to regulate the flow of fluid from the different subsystems.

[0123] In this regard, the TOC measurement system 112 may measure the TOC level at one of the microfluidic sample cells 132 in the microfluidic enclosure 124 that is connected between the respective first conduit 120 of the plurality of first conduits 120 and the second conduit 126 at the plurality of second conduits 126. When the TOC level measured at the respective microfluidic sample cell 132 is higher than a certain threshold, the other microchannels and microchambers in the TOC measurement system 112 can be activated and primed with samples drawn from the other subsystems to perform the differential analysis and to enable the controller 140 to diagnose and determine where the failure is occurring and to thereby determine the source of the TOC exceeding the certain threshold.Attorney Docket No. 218079.023801 (IDF00022)

[0124] FIG. 5 is a top view of a non-limiting example of the microfluidic enclosure 124, according to some embodiments. The microfluidic enclosure 124 is shown including a microfluidic sample cell 132a forming a straight microchannel and having a single independent inlet as inlet 136a and a single independent outlet as outlet 138a. The microfluidic enclosure 124 is also shown including a microfluidic sample cell 132b forming a microchannel having a single independent inlet as inlet 136b and dual outlets as outlet 138b and outlet 138c. The microfluidic enclosure 124 is also shown including microfluidic sample cell 132c forming a straight microchamber with single independent inlet as inlet 136c and outlet as outlet 138d. In some embodiments, the microfluidic enclosure 124 can include microfluidic sample cell 132a, microfluidic sample cell 132b, microfluidic sample cell 132c, other configurations of microfluidic sample cells, or any combinations thereof.

[0125] FIG. 6 is a top view of the portion of the TOC measurement system 112, according to some embodiments.

[0126] The microfluidic enclosure 124 is shown including a microfluidic sample cell 132d forming one straight microchannel with dual inlets as inlet 136d and inlet 136e and a single independent outlet as outlet 138e. The microfluidic enclosure 124 is also shown including a microfluidic sample cell 132e forming one straight microchamber with a single independent inlet as inlet 136f and double outlets as outlet 138f and outlet 138g. In some embodiments, the microfluidic enclosure 124 can include microfluidic sample cell 132d, microfluidic sample cell 132e, other microfluidic sample cells 132, or any combinations thereof.

[0127] FIG. 7 is a top view of portion of the TOC measurement system 112, according to some embodiments.

[0128] The microfluidic enclosure 124 is shown including microfluidic sample cell 132g forming a curved microchannel with single independent inlet as inlet 136g and outlet as outlet 138h. The microfluidic enclosure 124 is also shown including microfluidic sample cell 132h forming a straight microchamber with a single independent inlet as inlet 136h and outlet as outlet 138i, and a surface of the microfluidic sample cell 132h including a catalyzer substrate 168 having a microstructure forming a plurality of V-shaped ribs between the inlet 136h and outletAttorney Docket No. 218079.023801 (IDF00022)138i. The V-shaped ribs configured to interact with unoxidized compounds in the fluid. In some embodiments, the microfluidic enclosure 124 can include microfluidic sample cell 132g, microfluidic sample cell 132h, other microfluidic sample cell 132, or any combinations thereof.

[0129] It is to be appreciated that the configuration of each microfluidic sample cell 132 in the microfluidic enclosure 124 is not intended to be limiting, and that each microfluidic sample cell 132 can be straight or curved, and the microfluidic sample cell 132 can be connected to a single inlet, multiple inlets, single outlet, multiple outlets, or any combinations thereof.[0130JFIG. 8 is a front view of the portion of the TOC measurement system 112, according to some embodiments.

[0131] The microfluidic enclosure 124 is shown including two microchamber inlets shown as inlet 136j and inlet 136k and one microchannel inlet shown as inlet 1361. The microfluidic sample cell 132 can be made of a microfabricated quartz. In some embodiments, the microfluidic sample cell 132 can be made of a synthetic silica. In addition, in some embodiments, the microfluidic sample cell 132 can be coated with a catalyzer substrate 168 coating an interior surface of the microfluidic sample cell 132. The catalyzer substrate 168 is configured to accelerate oxidation of the fluid flowing through the microfluidic sample cell 132 in the microfluidic enclosure 124. In some embodiments, the catalyzer substrate 168 further includes a micropattern configured to contact unoxidized species in the fluid to increase a mixing level of the fluid in the microfluidic sample cell 132. For example, the microfluidic sample cell 132 can be a straight microchannel made of microfabricated quartz and include the catalyzer substrate on one or more inner surfaces of the microfluidic sample cell 132. In some embodiments, the catalyzer substrate 168 is titanium dioxide (TiO?).[0132JFIG. 9 is a front view of the portion of the TOC measurement system 112, according to some embodiments.

[0133] The microfluidic enclosure 124 is shown with two microchamber inlets 136m and 136n. In some embodiments, the microfluidic sample cell 132 formed to include the inlet 136m or inlet 136n, for example, can be made of a microfabricated quartzAttorney Docket No. 218079.023801 (IDF00022)or synthetic silica coupled with a substrate coated with V-shape ribs. In some embodiments, the V-shaped ribs in the microfluidic sample cell 132 can be micro structured TiO2.

[0134] All prior patents and publications referenced herein are incorporated by reference in their entireties.

[0135] Throughout the specification and claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise. The phrases "in one embodiment," “in an embodiment,” and "in some embodiments" as used herein do not necessarily refer to the same embodiment(s), though it may. Furthermore, the phrases "in another embodiment" and "in some other embodiments" as used herein do not necessarily refer to a different embodiment, although it may. All embodiments of the disclosure are intended to be combinable without departing from the scope or spirit of the disclosure.

[0136] As used herein, the term "based on" is not exclusive and allows for being based on additional factors not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meaning of "a," "an," and "the" include plural references. The meaning of "in" includes "in" and "on."

[0137] As used herein, the term “between” does not necessarily require being disposed directly next to other elements. Generally, this term means a configuration where something is sandwiched by two or more other things. At the same time, the term “between” can describe something that is directly next to two opposing things. Accordingly, in any one or more of the embodiments disclosed herein, a particular structural component being disposed between two other structural elements can be:disposed directly between both of the two other structural elements such that the particular structural component is in direct contact with both of the two other structural elements;disposed directly next to only one of the two other structural elements such that the particular structural component is in direct contact with only one of the two other structural elements;Attorney Docket No. 218079.023801 (IDF00022)disposed indirectly next to only one of the two other structural elements such that the particular structural component is not in direct contact with only one of the two other structural elements, and there is another element which juxtaposes the particular structural component and the one of the two other structural elements;disposed indirectly between both of the two other structural elements such that the particular structural component is not in direct contact with both of the two other structural elements, and other features can be disposed therebetween; orany combination(s) thereof.

[0138] As used herein “embedded” means that a first material is distributed throughout a second material.

Claims

Attorney Docket No. 218079.023801 (IDF00022)CLAIMSWhat is claimed is:

1. A system comprising:a first conduit;an inlet sensor configured to sense a first property of a fluid flowing through the first conduit;a microfluidic enclosure fluidly connected to the first conduit,wherein the microfluidic enclosure is disposed fluidly downstream of the inlet sensor;wherein the microfluidic enclosure comprises:a housing having an inlet and an outlet;a microfluidic sample cell disposed within the housing, wherein the microfluidic sample cell is at least partially transparent to ultraviolet radiation;wherein the inlet is fluidly connected to the first conduit; and an ultraviolet source disposed within the housing and configured to output ultraviolet radiation;a second conduit fluidly connected to the outlet; andan outlet sensor configured to sense a second property of the fluid as received from the microfluidic enclosure and the outlet sensor disposed downstream of the microfluidic enclosure.

2. The system of claim 1 , wherein the inlet sensor is a first conductivity sensor, and the outlet sensor is a second conductivity sensor.

3. The system of claim 2, further comprising a controller, wherein the controller is configured to:receive the first property,wherein the first property is a first conductivity;receive the second property,Attorney Docket No. 218079.023801 (IDF00022)wherein the second property is a second conductivity; anddetermine a total organic carbon (TOC) within the fluid using a difference between the first property and the second property.

4. The system of claim 3, wherein the first conductivity, the second conductivity, or a combination thereof, are adjusted using a temperature of the fluid to account for temperature variations in the fluid.

5. The system of claim 3, wherein the inlet sensor is configured to sense one or more properties of the fluid flowing through the first conduit, and the outlet sensor is configured to sense one or more other properties of the fluid flowing through the second conduit.

6. The system of claim 5, wherein the inlet sensor is further configured to sense a third property of the fluid flowing through the first conduit, and the outlet is further configured to sense a fourth property of the fluid flowing through the second conduit.

7. The system of claim 6, wherein the inlet sensor further comprises a first pH sensor and the outlet sensor further comprises a second pH sensor; andwherein the controller is further configured to:receive the third property sensed by the first pH sensor, andreceive the fourth property sensed by the second pH sensor;wherein the controller determines the TOC within the fluid using a difference between the third property as sensed by the first pH sensor and the fourth property as sensed by the second pH sensor.

8. The system of claim 5, wherein the inlet sensor is further configured to sense a fifth property of the fluid flowing through the first conduit, and the outlet is further configured to sense a sixth property of the fluid flowing through the second conduit, wherein the inlet sensor further comprises a first temperature sensor and the outlet sensor further comprises a second temperature sensor; andAttorney Docket No. 218079.023801 (IDF00022)wherein the controller is further configured to:receive the fifth property sensed by the first temperature sensor, andreceive the sixth property sensed by the second temperature sensor; wherein the controller determines the TOC within the fluid using a difference between the first property as sensed and adjusted using the fifth property as sensed by the first temperature sensor and the second property as sensed and adjusted using the sixth property as sensed by the second temperature sensor.

9. The system of claim 3, wherein the microfluidic enclosure comprises: at least one ultraviolet sensor,wherein the at least one ultraviolet sensor is configured to sense an amount of ultraviolet radiation emitted by the ultraviolet source.

10. The system of claim 9, wherein the controller is further configured to: receive a first ultraviolet measurement from the at least one ultraviolet sensor corresponding to the amount of ultraviolet radiation emitted by the ultraviolet source, wherein the controller determines a lifespan of the ultraviolet source using the first ultraviolet measurement.

11. The system of claim 1, wherein the microfluidic sample cell further comprising:a catalyzer substrate coating an interior surface of the microfluidic sample cell, the catalyzer substrate being configured to accelerate oxidation of the fluid in the microfluidic enclosure,wherein the catalyzer substrate further comprises a micro-pattern configured to contact the fluid to increase a mixing level of the unoxidized species in the fluid in the microfluidic sample cell.

12. A system comprising:a plurality of first conduits;Attorney Docket No. 218079.023801 (IDF00022)a plurality of inlet sensors configured to sense a first property of a fluid flowing through a respective one of the plurality of first conduits;a microfluidic enclosure fluidly connected to the plurality of first conduits, wherein the microfluidic enclosure is disposed fluidly downstream of the plurality of inlet sensors;wherein the microfluidic enclosure comprises:a housing having a plurality of inlets and a plurality of outlets; a plurality of microfluidic sample cells disposed within the housing, wherein the plurality of microfluidic sample cells are at least partially transparent to ultraviolet radiation;wherein the plurality of inlets are fluidly connected to respective ones of the plurality of first conduits; andan ultraviolet source disposed within the housing and configured to output ultraviolet radiation;a plurality of second conduits fluidly connected to the plurality of outlets; and a plurality of outlet sensors configured to sense a second property of the fluid as received from the microfluidic enclosure and disposed downstream of the microfluidic enclosure.

13. The system of claim 12, further comprising a flow controller to fluidly connect one or more of the plurality of first conduits for initiating a fluid test.

14. A dialysis system comprising:a water purification system configured to purify water for use in dialysis; and a total organic carbon sensing system comprising:a first conduit;an inlet sensor configured to sense a first property of the water flowing through the first conduit;a microfluidic enclosure fluidly connected to the first conduit, wherein the microfluidic enclosure is disposed fluidly downstream of the inlet sensor;Attorney Docket No. 218079.023801 (IDF00022)wherein the microfluidic enclosure comprises:a housing having an inlet and an outlet;a microfluidic sample cell disposed within the housing, wherein the microfluidic sample cell is at least partially transparent to ultraviolet radiation;wherein the inlet is fluidly connected to the first conduit; andan ultraviolet source disposed within the housing and configured to output ultraviolet radiation;a second conduit fluidly connected to the outlet; andan outlet sensor configured to sense a second property of the water as received from the microfluidic enclosure and disposed downstream of the microfluidic enclosure.

15. The dialysis system of claim 14, wherein the controller is configured to enable the ultraviolet source to oxidize organic compounds within the water.

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