Powerwash systems and methods of use thereof

Abstract

Disclosed herein are powerwash systems and methods of use therein including sampling probes with a transport channel including an inlet, an outlet, and a sampling inlet deposed between the inlet and the outlet and configured to receive at least a portion of a sample into the sampling inlet of the transport channel and configured to transport the sample via a transport fluid that flows from the inlet to the outlet of the transport channel; and a wash channel with a wash channel inlet and a wash channel outlet, where the wash channel is configured to transport one or more wash fluids from the wash channel inlet to the wash channel outlet, and where the one or more wash fluids are configured to exit the wash channel outlet and flow adjacent to the transport channel and toward the sampling inlet.

Description

Sciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTPOWERWASH SYSTEM AND METHODS OF USE THEREOFCROSS REFERENCE TO RELATED APPLICATION

[0001] This patent application claims the benefit of U.S. Provisional Patent Application No. 63 / 760,927, filed on February 20, 2025, which is incorporated by reference in its entirety herein.BACKGROUND

[0002] Mass spectrometry (MS) is an analytical technique for measuring mass-to-charge ratios of molecules, with both qualitative and quantitative applications. MS can be useful for identifying unknown compounds, determining the structure of a particular compound by observing its fragmentation patterns, and quantifying the amount of a particular compound in a sample. Mass spectrometers separate and detect chemical entities as ions, such that a conversion of the analytes to charged ions must occur prior to entering the mass spectrometer.

[0003] In the analysis of complex sample matrices (e.g., biological, environmental, and food samples), many current MS techniques require extensive pre-treatment steps to be performed on the sample prior to MS detection / analysis of the analyte of interest. Such pre-analytical steps can include sampling (i.e., sample collection) and sample preparation (separation from the matrix, concentration, fractionation and, if necessary, derivatization). It has been estimated, for example, that more than 80% of the time of overall analytical processing can be spent on sample collection and preparation to enable the analyte's detection via MS or to remove potential sources of interference present in the sample matrix, while increasing potential sources of dilution and / or error at each sample preparation stage.

[0004] Typically, in ESI, a liquid sample is continuously discharged into an ionization chamber from within an electrically conductive capillary, while an electric potential difference between the capillary and a counter electrode generates a strong electric field within the ionization chamber that electrically charges the liquid sample. This electric field causes the liquid discharged from the capillary to disperse into a plurality of charged microdroplets drawn toward the counter electrode if the charge imposed on the liquid's surface is strong enough to overcome the surface tension of the liquid (i.e., the particles attempt to disperse the charge and return to a lower energy state). As solvent within the micro-droplets evaporates during desolvation in the ionization chamber, charged analyte ions can then enter a sampling orifice of the counter electrode for subsequent mass spectrometric analysis.Sciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCT

[0005] Ideally, sample preparation and sample introduction techniques for MS should be fast, reliable, reproducible, inexpensive, and in some respects, amenable to automation. One example of an improved sample preparation technique is solid-phase microextraction (SPME), which essentially integrates sampling, sample preparation, and extraction into a single solvent-free step. Generally, SPME devices utilize a fiber or other surface (e.g., blades, micro-tips, pins, or mesh) coated with an extracting phase to which analytes within the sample can be preferentially adsorbed when the device is inserted into the sample. Because extraction can take place in situ by inserting a biocompatible device directly into tissue, blood, or other biological matrix for a short period of time, SPME does not require any sample collection. Alternatively, SPME devices can be used for ex vivo analysis using a small amount of a collected sample (i.e., a sample aliquot).

[0006] Though SPME is generally considered to be accurate and simple and can result in decreased sample preparation time and disposal costs, the mass-spectrometric based analysis of SPME-prepared samples may require additional equipment and / or time-consuming steps to ionize the analyte from the SPME device directly or to desorb the analytes from the SPME device prior to ionization as required for mass spectrometry (MS). By way of example, various ionization methods have been developed that can desorb / ionize analytes from condensed-phase samples with minimal sample handling (e.g., desorption electrospray ionization (DESI) and direct analysis in real time (DART), which “wipe-off’ analytes from the samples by exposing their surfaces to an ionizing medium such as a gas or an aerosol). However, such techniques can also require sophisticated and costly equipment and may be amenable only for a limited class of highly -volatile small molecules.

[0007] Alternatively, additional desorption steps have been utilized to extract the analytes from the SPME device prior to ionization via ionization techniques other than DESI or DART. For example, because electrospray ionization (ESI) is one of the most common ionization methods and requires the analyte to be in solution, some users have utilized liquid desorption and subsequent purification / separation of the extracted / enriched analytes via high-performance liquid chromatography (HPLC) prior to MS analysis. However, liquid desorption prior to HPLC may: i) require an extended processing step to transfer the analyte from the SPME coating to a relatively large volume liquid phase due to requirements imposed on the HPLC mobile phase (e.g., a weak solvent strength); ii) can decrease throughput; iii) introduce potential sources of error; iv) increase dilution; and v) cannot be easily automated. Some users have instead proposed substantial modifications to the standard electrospray ion source itself, which can be costly and time consuming.Sciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCT

[0008] Accordingly, there is a need for improved and / or reduced-cost systems that enable fast-coupling to MS systems with minimal alterations to the front-end while maintaining sensitivity, simplicity, selectivity, speed, and throughput.BRIEF SUMMARY

[0009] Further and alternative aspects and features of the disclosed principles will be appreciated from the following detailed description. As will be appreciated, the compositions and methods disclosed herein are capable of being carried out and used in other and different embodiments, and capable of being modified in various respects. Accordingly, it is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and do not restrict the scope of the appended claims.

[0010] In one aspect, the disclosure features a sampling probe including a transport channel including an inlet, an outlet, and a sampling inlet deposed between the inlet and the outlet and configured to receive at least a portion of a sample into the sampling inlet of the transport channel and configured to transport the sample via a transport fluid that flows from the inlet to the outlet of the transport channel and a wash channel including a wash channel inlet and a wash channel outlet, where the wash channel is configured to transport one or more wash fluids from the wash channel inlet to the wash channel outlet, and where the one or more wash fluids are configured to exit the wash channel outlet and flow adjacent to the transport channel and toward the sampling inlet.

[0011] In some embodiments, the transport channel and / or the wash channel includes a tubular or cannular shape. In some embodiments, the transport fluid comprises a liquid solvent. In some embodiments, the transport fluid has a higher flow rate at the outlet compared to the inlet, thereby creating a reduction in pressure at the sampling inlet. In some embodiments, the reduction in pressure enables aspiration of a sample at the sampling inlet. In some embodiments, the wash channel is adjacent to the transport channel. In some embodiments, the wash channel circumferentially surrounds the transport channel. In some embodiments, the wash channel outlet is from about 1 mm to about 25 mm, from about 2 mm to about 20 mm, from about 3 mm to about 15 mm, from about 4 mm to about 10 mm, or from about 5 mm to about 8 mm from the sampling inlet. In some embodiments, the one or more wash fluids include at least a first fluid; alternatively, at least a second fluid; alternatively, at least a third fluid. In some embodiments, the first, second, and / or third fluids are selected from the group consisting of an aqueous based solvent, an organic based solvent, and air. In some embodiments, the sampling probe of any preceding embodiment furtherSciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTincludes a liquid catch, where the liquid catch is configured to collect a bolus of liquid. In some embodiments, the liquid catch is further configured to release the bolus of liquid to flow uniformly around and adjacent to the transport channel toward the sampling inlet. In some embodiments, the sampling probe includes more than one wash channel. In some embodiments, the one or more wash fluids are configured to flow over the sampling inlet.

[0012] In one aspect, the disclosure features a method of washing the sampling probe of any preceding embodiment including: submerging the sampling inlet of the transport channel in a liquid sample; aspirating at least a portion of the sample into the sampling inlet of the transport channel; removing the sampling inlet of the transport channel from the liquid sample; and washing the sampling inlet of the transport channel.

[0013] In some embodiments, the washing of the sampling inlet of the transport channel includes collecting at least a first bolus of liquid in a liquid catch. In some embodiments, the washing of the sampling inlet of the transport channel further includes releasing the first bolus of liquid uniformly around and adjacent to the transport channel toward the sampling inlet. In some embodiments, the washing of the sampling inlet of the transport channel further includes collecting a second bolus of liquid in the liquid catch and releasing the second bolus of liquid uniformly around and adjacent to the transport channel toward the sampling inlet. In some embodiments, the first bolus of liquid and the second bolus of liquid are different liquids and / or have different concentrations of molecular species. In some embodiments, the washing of the sampling inlet of the transport channel further includes flowing a gas through the liquid catch and uniformly around and adjacent to the transport channel toward the sampling inlet. In some embodiments, the gas includes nitrogen, CO2, oxygen, air, argon, helium, or combinations thereof. In some embodiments, the gas is configured to flow continuously or to flow in a pulsed manner. In some embodiments, the washing the sampling inlet of the transport channel substantially eliminates sample carry-over (e.g., where carryover represents detection and interference of analytes from previous samples).BRIEF DESCRIPTION OF THE DRAWINGS

[0014] An understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:

[0015] FIG. 1 is a schematic of a cross-sectional view of a powerwash system illustrating several flow paths of the system.Sciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCT

[0016] FIG. 2 is an enlarged schematic of a cross-sectional view of a powerwash system illustrating several flow paths and structures of the system.

[0017] FIGS. 3A and 3B are images of the outside surface of the second tube illustrating precipitated sample 195 on the outside surface of the second tube (FIG. 3 A) and rivulet 191 flowing in a thin stream on the outside surface of the second tube (FIG. 3B) after using a conventional washing method.

[0018] FIG. 4 is an ion chromatogram illustrating the inconsistent detection of sample carry-over after the injection of several blanks.

[0019] FIGS. 5A-5E are images of the tip of one embodiment of a powerwash system illustrating a method of washing the outside surface of the second tube.

[0020] FIGS. 6A and 6B are ion chromatograms illustrating the lack of carry-over of the sample from one injection to the next. FIG. 6A shows the full height of the parent ion peaks.FIG. 6B shows the same parent ion peaks with an enlarged baseline with arrows indicating where a carry-over peak would be seen if any carry-over was present.DETAILED DESCRIPTIONI. Introduction

[0021] Conventional sampling for analytical analysis (e.g., MS / MS) is typically done with autosamplers or sampling devices that rely on high pressure valves to introduce the sample aliquot into the transport stream. In these cases, the transport flow path is pressurized, where the sample is at ambient pressure. Thus, a pressure valve is required to enable the entry of sample into the pressurized stream. Carry-over in this system includes the flow path and the internal surface of the valve being exposed to the sample. The flow path includes a sampling needle, which is also exposed to the sample. Liquid chromatography systems include even more components (e.g., pressure valves and injectors) and are notorious for the carry-over of analytes from sample to sample as the pressure cycling leads to crystallization of dissolved components and scoring of the stator and rotor. The scratches may act as traps, compounding the wash out issues of the injector. In contrast to the transport channel, channels that direct the flow within the injector are not continuously washed by the transport fluid as the path is switched. Each switch exposes additional surfaces to the sample without a wash. The resulting carry-over of analytes limits the analytical analysis (e.g., MS / MS) by cross-contamination and signal merging.

[0022] The powerwash system disclosed herein eliminates the conventional injector and introduces a novel washing process that substantially eliminates carry-over including carry-Sciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTover due to the sampling needle. For example, a sampling probe as shown in FIG. 1 includes a transport channel in which a fluid travels from an inlet (transport fluid in) to an outlet (transport and sample flow out). A sample may be introduced (e.g., via Venturi effect, which creates a negative pressure gradient at the sample inlet, enabling sample aspiration) at a sample inlet deposed between the transport channel inlet and outlet (adjacent to the arrow pointing to the outside surface of OPI tube shown in FIG. 1). The tip of the sampling probe may be submerged into a sample liquid, where an aliquot of sample is aspirated into the transport fluid. The tip of the sampling probe may then be removed from the sample liquid. However, some analytes in the sample may adhere to the outside surface of the OPI tube (as shown, for example, in FIG. 3 A), which may be removed using a powerwash system and method as disclosed herein, substantially eliminating carry-over of the analytes from sample to sample. A gas and / or liquid is flowed into the wash channel (powerwash channel) and exits the wash channel outlet (powerwash liquid / gas exit) and enters a catch or powerwash focusing nozzle, facilitating even distribution of the liquid and / or gas over the outside surface of the OPI tube and effectively removing the analytes. The powerwash system offers sampling of pL sized aliquots at ambient pressure without the need of a pressure valve. The transport channel is continuously washed by the transport fluid. The powerwash system introduces a device and methods for washing the sampling tip and allows high throughput operations from about 0.1 to about 0.5Hz without substantially any carry-over.

[0023] The powerwash system includes an additional channel(s) that bring(s) wash liquid to the outside of the sampling tip. The channels may be set up to deliver gas or liquid in a continuous stream or as a pulse. Multiple channels may be used to allow the use of a combination of liquid and gas, as well as operation of one channel continuously while pulsing the other.II. Definitions

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the methods described herein belong. Any reference to standard methods refers to the most recent available version of the method at the time of filing of this disclosure unless otherwise indicated.

[0025] For any method disclosed herein that includes discrete steps, the steps may be conducted in any feasible order. And, as appropriate, any combination of two or more steps may be conducted simultaneously.Sciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCT

[0026] All headings are for the convenience of the reader and should not be used to limit the meaning of the text that follows the heading, unless so specified.

[0027] The words "preferred" and "preferably" refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful and is not intended to exclude other embodiments from the scope of the invention.

[0028] The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Such terms will be understood to imply the inclusion of a stated step or element or group of steps or elements but not the exclusion of any other step or element or group of steps or elements.

[0029] The singular form "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. These articles refer to one or to more than one (i.e., to at least one). The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. As used herein, the term "or" is generally employed in its usual sense including "and / or" unless the content clearly dictates otherwise. The term "and / or" means any one or more of the items in the list joined by "and / or". As an example, "x and / or y" means any element of the three-element set {(x), (y), (x, y)}. In other words, "x and / or y" means "one or both of x and y". As another example, "x, y, and / or z" means any element of the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, "x, y and / or z" means "one or more of x, y and z".

[0030] Where ranges are given, endpoints include all numbers subsumed within that range (e.g, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc.). Furthermore, unless otherwise indicated or otherwise evident from the context and understanding of one of ordinary skill in the art, values that are expressed as ranges can assume any specific value or subrange within the stated ranges in different embodiments of the disclosure, to the tenth of the unit of the lower limit of the range, unless the context clearly dictates otherwise. Herein, "up to" a number (for example, up to 50) includes the number (for example, 50). The term "in the range" or "within a range" (and similar statements) includes the endpoints of the stated range.

[0031] Reference throughout this specification to “one aspect (or embodiment),” “an aspect (or embodiment),” “certain aspects (or embodiments),” or “some aspects (orSciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTembodiments),” etc., means that a particular feature, configuration, composition, or characteristic described in connection with the aspect is included in at least one aspect of the disclosure. Thus, the appearances of such phrases in various places throughout this specification are not necessarily referring to the same embodiment of the disclosure.Furthermore, the particular features, configurations, compositions, or characteristics may be combined in any suitable manner in one or more aspects.

[0032] Unless otherwise indicated, all numbers expressing quantities of components, molecular weights, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about." As used herein in connection with a measured quantity, the term "about" refers to that variation in the measured quantity as would be expected by the skilled artisan making the measurement and exercising a level of care commensurate with the objective of the measurement and the precision of the measuring equipment used. The term "about" is used in connection with a numerical value throughout the specification and the claims denotes an interval of accuracy, familiar and acceptable to a person skilled in the art. In general, such an interval of accuracy is + / -10%. Thus, "about" can be understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1 %, 0.5%, 0.1 %, 0.05%, 0.01 %, or 0.001 % greater or less than the stated value. Accordingly, unless otherwise indicated to the contrary, the numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0033] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. All numerical values, however, inherently contain a range necessarily resulting from the standard deviation found in their respective testing measurements.

[0034] The term "exemplary" means serving as a non-limiting example, instance, or illustration. As utilized herein, the terms "e.g.," and "for example" set off lists of one or more non-limiting aspects, examples, instances, or illustrations.

[0035] As used herein, the term "substantially" refers to the qualitative condition of exhibiting total or near-total extent or degree of a characteristic or property of interest.Biological and chemical phenomena rarely, if ever, go to completion and / or proceed toSciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTcompleteness or achieve or avoid an absolute result. The term "substantially" is therefore used herein to capture the potential lack of completeness inherent in many biological and chemical phenomena. For example, "substantially" may refer to being within at least about 20%, alternatively at least about 10%, alternatively at least about 5% of a characteristic or property of interest.

[0036] As used herein, the term “fixedly positioned” as referring to an element indicates that the position of that element is not adjustable by a user.III. Powerwash System

[0037] The present disclosure is generally related to sampling systems for delivering samples to an analytical instrument (e.g., mass spectrometer). In accordance with various aspects of the present disclosure and referring to FIG. 2, a sampling probe 100 is used to introduce samples to the analytical instrument, where the sampling probe includes a transport channel 145 and 150, which includes an outer transport channel 150 and an inner transport channel 145, which is disposed co-axially within the outer transport channel 150 (e.g., a channel within a channel). Transport channel 145 and 150 include an inlet 120, an outlet 110, and a sampling inlet 130 deposed between the inlet 120 and the outlet 110 and further deposed between the outer transport channel 150 and the inner transport channel 145, configured to receive at least a portion of a sample into the sampling inlet 130 of the transport channel 145 and 150 and configured to transport the sample via a transport fluid that flows from the inlet 120 to the outlet 110 of the transport channel 145 and 150. Sampling probe 100 also includes a wash channel 160 including a wash channel inlet 140 and a wash channel outlet 180, where the wash channel 160 is configured to transport one or more wash fluids from the wash channel inlet 140 to the wash channel outlet 180, and where the one or more wash fluids are configured to exit the wash channel outlet 180 and flow adjacent to the transport channel 150 along the outer surface 190 and toward the sampling inlet 130 located at the tip of the sampling probe 100. The wash channel 160 may circumferentially surround outer transport channel 150 or may be disposed adjacent to outer transport channel 150. In some embodiments, sampling probe 100 also includes catch 170 configured to receive a wash liquid and / or gas and distribute it evenly over the tip of sampling probe 100.

[0038] In some embodiments, the sampling probe is in fluid communication with an inlet of an analytical instrument. In some embodiments, the sampling probe is in fluid communication with an ion source for discharging a liquid containing one or more analytesSciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCT(e.g., via an electrospray ionization probe) through an ionization chamber and into a mass spectrometer. In general, the powerwash system includes a fluid handling system including one or more fluidic conduits, valves, controller, and / or pumps for controlling the flow of liquid in the transport channel between the inlet and outlet of the sampling probe and into an analytical instrument (e.g., ion source of a mass spectrometer) and for controlling the flow of liquid and / or gas through the wash channel.

[0039] In some embodiments, an ion source can have a variety of configurations but is generally configured to generate ions of analytes contained within a sample that is received from the sampling probe. For example, an electrospray electrode, which can include a capillary that is fluidly coupled to the sampling probe, terminates in an outlet end that at least partially extends into the ionization chamber and discharges the transport fluid therein. An outlet end of the electrospray electrode can atomize, aerosolize, nebulize, or otherwise discharge (e.g., spray with a nozzle) the transport fluid into the ionization chamber to form a plume including a plurality of micro-droplets generally directed toward (e.g., in the vicinity of) the curtain plate aperture and vacuum chamber sampling orifice. In some embodiments, the mass spectrometer is a sector, a single quadrupole, a triple quadrupole, a Qtof, a Tof, an ion trap, a Fourier-transform ion cyclotron resonance mass spectrometer, or a hybrid instrument using a combination of the listed mass separation techniques.

[0040] Only for the purposes of illustration, a non-limiting example is described to facilitate a more complete understanding of the sampling probe, as disclosed herein. The sampling probe may be used in conjunction with the system described in Figure 2 of “Fluid Dynamics of the Open Port Interface for High-Speed Nanoliter Volume Sampling Mass Spectrometry” Anal. Chem. 2021, 93, 24, 8559-8567 (Chang Liu et al.), which is herein incorporated by reference, in its entirety. The OPI capture port A, shown in Figure 2 of the reference, can be replaced with the sampling probe 100, as disclosed herein. In operation, the inside of the transport channel is continuously washed by the flow of a transport fluid. While the inside of the transport channel is continuously washed, the outside of the tip may retain trace amounts of sample 195 on its exterior after immersion of the tip into a sample well. The outer surface 190 of the outer transport channel 150 also requires wash, especially near the sampling inlet 130. The wash of outer surface 190 involves a release of a bolus of liquid from a wash channel 160 through a wash channel outlet 180, to flow the wash liquid over the outer (exterior) surface 190. The wash channel 160 and its outlet 180 also provide the means to introduce a different liquid into the inner transport channel 145, which may provide an alternate chemistry for washing of the inside of the transport channel and / or conduit.Sciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTAlternatively, the washing steps can be used to introduce a bolus of wash liquid before, during, or sample introduction to enable chemical interaction with the sample and or transport fluid.

[0041] It will be appreciated that sampling probes in accordance with the present teachings can also have a variety of configurations and sizes. By way of non-limiting example, the dimensions of an inner diameter of the inner transport channel can be in a range from about 1 micron to about 1 mm (e.g., 250 microns), with dimensions of the outer diameter of the inner transport channel being in a range from about 100 microns to about 2 millimeters (e.g., 1,200 microns). Also, by way of example, the dimensions of the inner diameter of the outer transport channel can be in a range from about 100 microns to about 3 millimeters (e.g., 1,200 microns), with the typical dimensions of the outer diameter of the outer transport channel being in a range from about 150 microns to about 3.5 millimeters (e.g., 1,600 microns). By way of example, the dimensions of the inner diameter of the wash channel can be in a range from about 2 millimeters to about 5 millimeters, with the typical dimensions of the outer diameter of the wash channel being in a range from about 3 millimeters to about 7 millimeters. By way of example, the dimensions of the inner diameter of the catch can be in a range from about 2 millimeters to about 7 millimeters, with the typical dimensions of the outer diameter of the catch being in a range from about 3 millimeters to about 15 millimeters. The cross-sectional shapes of the inner transport channel and / or the outer transport channel and / or wash channel and / or catch can be circular, elliptical, superelliptical (i.e., shaped like a superellipse), or even polygonal (e.g., square). In some embodiments, the inner transport channel does not extend to the tip of the sampling probe. In other words, the inner transport channel is recessed relative to the outer transport channel. The inner transport channel can be recessed 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm from the tip of the sampling probe. In some embodiments, the distance between the catch and the tip of the sampling probe is from about 0.5 cm to about 10 cm. In some embodiments, the distance between the catch and the tip of the sampling probe is about 0.5 cm, about 1 cm, about 1.5 cm, about 2 cm, about 2.5 cm, about 3 cm, about 3.5 cm, about 4 cm, about 4.5 cm, about 5 cm, about 6 cm, about 7 cm, about 8 cm, about 9 cm, or about 10 cm.IV. Methods of Using a Sampling Probe

[0042] Disclosed herein are methods using a sampling probe. In operation, the tip of the sampling probe is quickly dipped into a sample vial where a small aliquot is pinned onto itsSciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTsurface. The aliquot is then drawn into the transport fluid by aspiration of the vortex flow. Internal surfaces of the transport channel are continuously washed by the transport fluid, but the outside surface of the tip of the sampling probe is not washed by the transport fluid. Even if the transport fluid is increased to overflow mode, the wicking back along the outside wall, prior to an overflow drop separating from the tip, is uncontrolled and subject to localized beading (sections of the surface being preferentially wetted) due to its history, resulting in inconsistent washing away of analytes from the surface. Hence, the sampling only process typically results in about 1 -4% carry-over from sample to sample (as shown, for example, in FIG. 3 A). A burst of liquid may be introduced through the powerwash exit to wash the OPI outside surface, but natural variation in hydrophobicity of the outside wall leads to an uneven wash due to beading and rivulet formation (FIG. 3B shows a rivulet flowing and washing only a small area of the outside surface).

[0043] Carry-over is reduced, but may, nonetheless, sporadically re-appear in an isolated dried island of wash liquid or sample, which acts as a contaminant when contacted by the meniscus of a sample in a new sample well or by wicking action of the sample up the outside of the sampling probe (e.g., FIG. 4 shows the sporadic appearance of contaminant peaks in subsequence sample blanks). The wash process was further improved by the introduction of a catch or powerwash focusing nozzle that distributes the wash liquid equally around the outside surface of the sampling probe. The catch effectively eliminates the carry-over but may cause peak shape distortion. Specifically, the wash liquid may either be dripped off the tip into waste or aspirated into the transport fluid. In either case, the powerwash transition into vortex mode, due to the powerwash liquid remnants on the outside surface, adversely affects the peak shape and hence peak definition. Adding a burst of gas flow through the catch or focusing nozzle after the powerwash liquid is delivered removes the bulk of the liquid remnants and restores the peak shape. In sum, after retrieving the sampling probe tip from the sample liquid a quick burst of liquid collects inside the catch or focusing nozzle and exits uniformly, the liquid symmetrically surrounds the outside OPI surface and starts to form a drop at the tip (or drips if the burst is longer). The wash liquid is then blown off the tip by a gas burst.

[0044] A non-limiting example is shown in FIGS. 5A- 5E. FIG. 5A shows the dry tip of a sampling probe. FIG. 5B, after the tip has been dipped into the sample liquid and a sample aliquot introduced into the transport fluid, shows liquid beginning to fill the catch from the wash channel outlet illustrated by the appearance of a meniscus of the wash fluid in the catch and a small amount of wash fluid beginning to wick along the outside of the outer transportSciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTchannel toward the tip. FIG. 5C shows the wash fluid continuing to enter the catch and forming a drop at the tip of the sampling probe. FIG. 5D shows the bulk of the wash fluid leaving the catch and dripping from the tip of the sampling probe (e.g., into a waste reservoir). FIG. 5E shows a bolus of air exiting the catch to remove remaining wash fluid from the tip of the sampling probe.

[0045] In some cases, the air burst may not have removed all the liquid from the outside surface of the outer transport channel of the sampling probe. In some embodiments, the outer transport channel can be formed of or be coated with a composition that minimizes liquid adhesion such as a hydrophobic (e.g., a fluoropolymer, silicone), lipophobic, or omniphobic material. In some embodiments, the surface may be restored (e.g., liquid removed) by dipping the tip of the sampling probe into a wash liquid, where the surface tension of the meniscus of the wash liquid helps to pull the remaining liquid off the tip as the sampling probe is withdrawn.

[0046] In some embodiments, the volumetric flow rate through the outer transport channel can be temporarily increased relative to the volumetric flow rate through the inner transport channel such that the transport fluid overflows from the open end of the sampling inlet. In some embodiments, the flow rate is adjusted by a pump. In some embodiments, the flow rate is adjusted by changing the flow rate of a nebulizer gas in the ionization chamber. A flow of gas flowing adjacent to the liquid transport fluid exiting an electrospray probe will apply a “pulling” force (Venturi effect). For example, increasing the flow rate of the nebulizer gas increases the flow rate of the transport fluid through the inner transport channel. In some embodiments, the nebulizer gas includes a nebulizer gas configured to dry the liquid sample. In some embodiments, the nebulizer gas includes hydrogen, helium, nitrogen, argon, oxygen, carbon dioxide, SFe, or combinations thereof. In some embodiments, the nebulizer gas flows at a rate from about 0.5 L / min to about 50 L / min or from about 1 L / min to about 20 L / min.

[0047] It will be appreciated in light of the present teachings that the exemplary methods and systems described can be utilized in an automated protocol and can reduce and / or eliminate the need for complex and time-consuming sample preparation steps such as liquid chromatography. In accordance with various aspects of the present teachings, an actuation mechanism (e.g., robotic arm, stage, electromechanical translator, step motor, etc.) can be utilized to deliver under the control of a controller (not shown) and without human intervention one or more samples to the sampling space of the sampling probe, timed forSciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTexample to coincide with the configuration of the fluid handling system and used to automate one or more washing processes as disclosed herein.

[0048] The following examples further illustrate the invention but should not be construed in any way as limiting its scope.EXAMPLESExample 1

[0049] FIG. 4 is an ion chromatogram that showed a primary analyte peak, Chlorhexidine (100 pg / pL), from a sample followed by several minor analyte peaks representing carry-over still present on the outside of the transport channel after using a conventional wash method, which contaminates the subsequent blank samples introduced into the transport fluid. The transport liquid is Methanol at a flowrate of 400 pL / min. For example, FIG. 3A showed a residual amount of analyte precipitated (arrow) on the outside of the transport channel. FIG. 3B showed a wash step without a catch that formed a rivulet of liquid (arrow), washing only a small area of the outside of the transport channel and leaving residual sample liquid behind.Example 2

[0050] FIG. 6A is an ion chromatogram that shows the introduction of sample followed by washing the sampling probe with a catch. A sample without any analytes (e.g., a blank) was then introduced into the transport fluid. The introduction of sample followed by a blank was repeated three times. FIG. 6B is the same ion chromatogram as FIG. 6A with an enlarged baseline. FIG. 6B showed that substantially no carry-over was present in the blank samples. The arrows indicate where a carry-over peak would have occurred if present. During the sampling event, 1 pL of analyte, Reserpine at 10 ng / pL, was introduced into the transport flow, 400 pL / min of methanol, to generate the signal peak. Subsequent wash consisted of the following steps, through the catch: a burst of methanol wash liquid, 40 pL, followed by a single, 2 second, burst of gas that delivered 65 mL of air. These wash steps were performed prior to testing of the blank well.

[0051] All features disclosed in the specification, including the claims, abstracts, and drawings, and all the steps in any method or process disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. Each feature disclosed in the specification, including the claims, abstract, and drawings, can be replaced by alternative features serving the same, equivalent or similarSciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTpurpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0052] It will be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.

Claims

Sciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTClaims:

1. A sampling probe comprising:a transport channel comprising an inlet, an outlet, and a sampling inlet deposed between the inlet and the outlet and configured to receive at least a portion of a sample into the sampling inlet of the transport channel and configured to transport the sample via a transport fluid that flows from the inlet to the outlet of the transport channel; anda wash channel comprising a wash channel inlet and a wash channel outlet, wherein the wash channel is configured to transport one or more wash fluids from the wash channel inlet to the wash channel outlet, and wherein the one or more wash fluids are configured to exit the wash channel outlet and flow adjacent to the transport channel and toward the sampling inlet.

2. The sampling probe of claim 1, wherein the transport channel and / or the wash channel comprises a tubular or cannular shape.

3. The sampling probe of claim 1 or claim 2, wherein the transport fluid comprises a liquid solvent.

4. The sampling probe of any one of claims 1 to 3, wherein the transport fluid has a higher flow rate at the outlet compared to the inlet, thereby creating a reduction in pressure at the sampling inlet.

5. The sampling probe of claim 4, wherein the reduction in pressure enables aspiration of a sample at the sampling inlet.

6. The sampling probe of any one of claims 1 to 5, wherein the wash channel is adjacent to the transport channel.

7. The sampling probe of claim 6, wherein the wash channel circumferentially surrounds the transport channel.

8. The sampling probe of any one of claims 1 to 7, wherein the wash channel outlet is from about 1 mm to about 25 mm, from about 2 mm to about 20 mm, from about 3Sciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTmm to about 15 mm, from about 4 mm to about 10 mm, or from about 5 mm to about 8 mm from the sampling inlet.

9. The sampling probe of any one of claims 1 to 8, wherein the one or more wash fluids comprise at least a first fluid; alternatively at least a first fluid and a second fluid; or alternatively at least a first fluid, a second fluid, and a third fluid.

10. The sampling probe of claim 9, wherein the first, second, and / or third fluids are selected from the group consisting of an aqueous based solvent, an organic based solvent, and air.

11. The sampling probe of any one of claims 1 to 10 further comprising a liquid catch, wherein the liquid catch is configured to collect a bolus of liquid.

12. The sampling probe of claim 11, wherein the liquid catch is further configured to release the bolus of liquid to flow uniformly around and adjacent to the transport channel toward the sampling inlet.

13. The sampling probe of any one of claims 1 to 12, wherein the sampling probe comprises more than one wash channel.

14. The sampling probe of any one of claims 1 to 13, wherein the wash channel comprises more than one outlet.

15. The sampling probe of any one of claims 1 to 14, wherein the one or more wash fluids are configured to flow over the sampling inlet.

16. The sampling probe of any one of claims 1 to 15, wherein the transport channel further comprises an inner transport channel and an outer transport channel having an outer surface, wherein the inner transport channel is deposed co-axially within the outer transport channel.

17. A method of washing the sampling probe of any one of claims 1 to 16 comprising:submerging the sampling inlet of the transport channel in a liquid sample;Sciexrefno: 2024-24166-P-WO Lathrop ref no: 773729: DASC-005PCTaspirating at least a portion of the sample into the sampling inlet of the transport channel;removing the sampling inlet of the transport channel from the liquid sample; andwashing the sampling inlet of the transport channel.

18. The method of claim 17, wherein the washing of the sampling inlet of the transport channel comprises collecting at least a first bolus of liquid in a liquid catch.

19. The method of claim 18, wherein the washing of the sampling inlet of the transport channel further comprises releasing the first bolus of liquid uniformly around and adjacent to the transport channel toward the sampling inlet.

20. The method of claim 19, wherein the washing of the sampling inlet of the transport channel further comprises collecting a second bolus of liquid in the liquid catch and releasing the second bolus of liquid uniformly around and adjacent to the transport channel toward the sampling inlet.

21. The method of claim 20, wherein the first bolus of liquid and the second bolus of liquid are different liquids and / or have different concentrations of molecular species.

22. The method of any one of claims 18 to 21, wherein the washing of the sampling inlet of the transport channel further comprises flowing a gas through the liquid catch and uniformly around and adjacent to the transport channel toward the sampling inlet.

23. The method of claim 22, wherein the gas comprises nitrogen, CO2, oxygen, air, argon, helium, or combinations thereof.

24. The method of claim 22 or claim 23, wherein the gas is configured to flow continuously or to flow in a pulsed manner.

25. The method of any one of claims 17 to 24, wherein the washing the sampling inlet of the transport channel substantially eliminates sample carryover.

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