Probe for extraction of molecules of interest from a sample

Abstract

The present disclosure describes a device for generating ionized molecules for analysis in a mass spectrometer. The device includes: a mesh substrate coated with an extraction phase, the extraction phase comprising a polymer that absorbs a molecule of interest from a matrix, or a polymer and solid phase microextraction (SPME) particles having pores dimensioned to absorb a molecule of interest from a matrix, where the mesh substrate has a sufficiently open structure to allow fluid to flow through the mesh substrate; and a solid substrate connected to the mesh substrate to provide stability to the coated mesh substrate. Mass spectrometry systems that include such a device are also described. Methods of analyzing an analyte previously extracted from a matrix onto the device are also described.

Claims

1. A device for generating ionized molecules for analysis in a mass spectrometer, the device comprising: a mesh substrate coated with an extraction phase of substantially uniform thickness that is from about 0.2 m to about 50 m, the extraction phase comprising: a polymer that absorbs a molecule of interest from a matrix, or a polymer and solid phase microextraction (SPME) particles having pores dimensioned to adsorb a molecule of interest from a matrix, wherein the coated mesh substrate has a sufficiently open structure to allow fluid to flow through the coated mesh substrate; and a solid substrate connected to the mesh substrate to provide stability to the coated mesh substrate.

2. The device according to claim 1, wherein the mesh substrate comprises a plurality of connected or impregnated wires, filaments or strings.

3. The device according to claim 2, wherein the plurality of connected or impregnated wires, filaments or strings have a diameter from 50 micrometers to 0.5 millimeters.

4. The device according to claim 2, wherein the plurality of connected or impregnated wires, filaments or strings comprise a metal, a metal alloy, or a polymer substrate.

5. The device according to claim 4, wherein the metal, metal alloy, or polymer substrate is: stainless steel, nitinol, nickel, titanium, aluminum, brass, iron, bronze, or polybutylene terephthalate.

6. The device according to claim 1, wherein the mesh substrate has an open area of at least 20%.

7. The device according to claim 1, wherein the extraction phase has a thickness sufficient to include one or two layers of particles.

8. The device according to claim 1, wherein the extraction phase is loaded with an internal standard.

9. The device according to claim 1, wherein the solid substrate comprises a metal, a metal alloy, or a polymer.

10. The device according to claim 9, wherein the solid substrate comprises stainless steel, titanium, a nickel-titanium alloy, nitinol, polybutylene terephthalate, or a 3-D printed polymer.

11. The device according to claim 1, wherein the solid substrate comprises a metal or a metal alloy and the coated mesh substrate is welded to the solid substrate.

12. The device according to claim 2, wherein the plurality of connected or impregnated wires, filaments or strings are in a grid configuration.

13. The device according to claim 6, wherein the mesh substrate has an open area of from about 50% to about 60%.

14. A mass spectrometry system comprising: a source of a heated gas, or a heated and metastable gas; an inlet for a mass spectrometer; a nozzle fluidly connected to the source of the heated gas, or heated and metastable gas for directing a flow of the heated gas, or heated and metastable gas to the inlet; and a device according to claim 1 positioned coaxial to, and at about a 0 angle from, the nozzle and the mass spectrometer inlet; wherein the nozzle is positioned to direct the heated gas, or heated and metastable gas through the coated mesh substrate of the device to desorb and ionize at least a portion of compounds sorbed on the coated mesh substrate, and wherein the inlet is positioned to collect and transport at least a portion of the desorbed and ionized compound to the mass spectrometer for analysis.

15. A method for analyzing an analyte previously extracted from a matrix onto a device according to claim 1, the method comprising: flowing a heated gas, a metastable gas, or a heated and metastable gas through the coated mesh substrate to desorb and ionize the analyte sorbed on the coated mesh substrate; transporting the desorbed and ionized analyte to a mass spectrometer; and analyzing the ionized analyte by mass spectrometry.

16. The method according to claim 15, further comprising rinsing the coated mesh substrate with a rinsing solution at least once before flowing the heated gas, metastable gas, or heated and metastable gas through the coated mesh substrate.

17. The method according to claim 15, wherein the desorbing is performed along the coated mesh substrate to characterize a distribution gradient of analytes along the coated mesh substrate.

18. A method for measuring or identifying one or more component of interest in a sample, said method comprising the steps of: positioning a device according to claim 1 in the sample; adsorbing the one or more component of interest onto the extraction phase; removing the device from the sample; and exposing the device to sufficient energy to desorb and ionize the one or more component of interest, resulting in ionization and desorption of the one or more component of interest from the extraction phase into a mass spectrometer for measurement or identification.

19. The method according to claim 18, wherein exposing the device to sufficient energy to desorb and ionize the one or more component of interest comprises exposing the mesh substrate to a laser or a hot carrier gas.

20. A holder positioning one or more devices according to claim 1 between a nozzle that is fluidly connected to a source of a heated gas, a metastable gas, or a heated and metastable gas, and an inlet for a mass spectrometer so that ionized molecules desorbed from the coated mesh substrate are transported to the mass spectrometer, the holder comprising: connectors for each of the one or more devices, each of the connectors releasably securing one of the devices.

21. The holder according to claim 20, wherein the holder is sized and shaped to simultaneously hold up to twelve devices according to claim 1, and is sized and shaped to be fitted on an automated electrical actuator that positions the coated mesh substrate between the nozzle and the inlet for the mass spectrometer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an illustration that shows the overall procedure for the preparation of the SPME-TM devices including two main steps: preparation of the coating as well as welding of the coated mesh on the solid substrate.

(2) FIG. 2 is a photograph that shows a bare stainless steel mesh (7474 wires in.sup.1) after etching and conditioning.

(3) FIG. 3 is a photograph that shows a stainless steel mesh coated with C18-PAN after 5 coating steps.

(4) FIG. 4 is an SEM image of a stainless steel mesh coated with C18-PAN after 5 coating steps.

(5) FIG. 5 is an SEM image of the particle size C18 attached to the surface of the mesh after 5 coating steps.

(6) FIG. 6 is an SEM image of two filaments/strings coated with C18-PAN after 5 coating steps.

(7) FIG. 7 is an illustration that shows a scheme of the design used to construct the mesh-blade configuration used for the SPME-TM devices.

(8) FIG. 8 is an illustration that shows the experimental set up for SPME-TM extraction and desorption/ionization using direct analysis in real time (DART).

(9) FIG. 9 is an illustration that shows a scheme of the holder for SPME-TM for automated and stable desorption/ionizations using DART.

(10) FIG. 10 is a schematic of 12-SPME-TM DART holder. It can be used not only to perform concomitant extractions on a 96 well autosampler, but also automated and stable desorption/ionizations. The system is compatible with the automated rail commercialized by IonSense. Up to 12 SPME-TM devices can be easily installed or removed from the holder and spatial position can be accurately adjusted on the Z and Y axis.

(11) FIG. 11 is a graph that shows extraction time profiles for diazepam and cocaine, respectively. Extractions were performed using vortex agitator set-up at maximum speed (3200 rpm). Extractions from 1.5 mL of PBS spiked with 50 ppb of each analyte with 3 different TFME devices (n=6) for each extraction point. Extracts were analyzed using Thermo LC/MS on SRM mode.

(12) FIG. 12 is a graph that shows quantitative analysis of PBS spiked with cocaine (10 pg mL.sup.1 to 50 ng mL.sup.1) and its isotopologue [D.sub.3] cocaine (12 ng mL.sup.1). Bars represent the standard deviation of analysis for three replicates with independent SPME-TM devices.

(13) FIG. 13 is a graph that shows quantitative analysis of PBS spiked with diazepam (10 pg mL.sup.1 to 50 ng mL.sup.1) and its isotopologue [D.sub.5] diazepam (12 ng mL.sup.1). Bars represent the standard deviation of analysis for three replicates with independent SPME-TM devices.

(14) FIGS. 14A and 14B are graphs that show SPME-TM inter-mesh reproducibility; ion chronograms obtained after 1 min extraction from a solution spiked with 20 ppb of cocaine versus carry-over after 1 desorption/ionization cycle (FIG. 14A) or carry-over after 1 cleaning step (FIG. 14B).

(15) FIG. 15 is a graph that shows quantitative analysis of plasma spiked with cocaine (50 pg mL.sup.1 to 50 ng mL.sup.1) and its isotopologue [D.sub.3] cocaine (12 ng mL.sup.1).

(16) FIG. 16 is a graph that shows quantitative analysis of urine spiked with cocaine (50 pg mL.sup.1 to 50 ng mL.sup.1) and its isotopologue [D.sub.3] cocaine (12 ng mL.sup.1).

(17) FIG. 17 is a graph that shows quantitative analysis of plasma spiked with diazepam (500 pg mL.sup.1 to 50 ng mL.sup.1) and its isotopologue [D.sub.5] diazepam (12 ng mL.sup.1).

(18) FIG. 18 is a graph that shows quantitative analysis of urine spiked with diazepam (50 pg mL.sup.1 to 50 ng mL.sup.1) and its isotopologue [D.sub.5] diazepam (12 ng mL.sup.1).

(19) FIG. 19 is a graph that shows SPME-TM standard free calibration. Quantitative analysis of urine spiked with diazepam (500 pg mL.sup.1 to 50 ng mL.sup.1).

(20) FIG. 20 is a graph that shows SPME-TM standard free calibration. Quantitative analysis of urine spiked with cocaine (500 pg mL.sup.1 to 50 ng mL.sup.1).

(21) FIG. 21 is a graph that shows SPME-TM standard free calibration. Quantitative analysis of plasma spiked with cocaine (500 pg mL.sup.1 to 50 ng mL.sup.1).

(22) FIGS. 22A-22C show three graphs that illustrate ion chronograms of three controlled substances: heroin (FIG. 22A), propranolol (FIG. 22B), and stanozolol (FIG. 22C). 1 min extractions were performed using vortex agitator set-up at maximum speed (3200 rpm). Simultaneous extraction from 1.5 mL of PBS spiked with 20 ng mL.sup.1 of 21 substances described in Table 2. Analyses were performed using Thermo TSQ on MRM mode.

DETAILED DESCRIPTION

(23) The transitional term comprising is synonymous with including or containing and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.

(24) The transitional phrase consisting of excludes any feature, element, step, or ingredient not specified in the claim, but does not exclude additional components or steps that are unrelated to the invention such as impurities ordinarily associated with a composition.

(25) The transitional phrase consisting essentially of limits the scope of a claim to the specified materials, features or steps and those that do not materially affect the basic and novel characteristic(s) of the claimed invention.

(26) The subject matter disclosed herein relates to systems and methods that extract or enrich analytes of interest present in a sample, and that are then coupled to a thermal or solvent based desorption source of a mass spectrometer. The thermal or solvent based desorption source may use a heated gas with electronic excited-state species to desorb a molecule sorbed on the surface of the extractive device. The desorption source may be a direct analysis in real-time (DART) source.

(27) The system disclosed herein, when the extractive phase includes a polymer and solid phase microextraction (SPME) particles, may be referred to as solid phase microextraction-transmission mode (SPME-TM) as it can be used without further modification as a transmission mode (TM) substrate for desorbing a molecule that is adsorbed on the surface of the SPME device using a thermal or solvent based desorption technique. SPME-TM may integrate sample preparation and ambient ionization.

(28) The thermal or solvent based desorption device may use a heated gas with electronic excited-state species to desorb analytes that are sorbed on the extractive device. The heated gas with electronic excited-state species may be generated through, for example: Plasma Assisted Desorption/Ionization (PADI), Dielectric Barrier Discharge ionization (DBDI or DCBI), Desorption Atmospheric Pressure Chemical Ionization (DAPCI), Desorption Sonic Spray Ionization (DeSSI), Desorption Atmospheric Pressure Photoionization (DAPPI), Flowing Atmospheric-Pressure Afterglow (FAPA), desorption electrospray ionization (DESI), atmospheric laser desorption ionization, corona discharge, inductively coupled plasma (ICP), or glow discharge.

(29) A solid-phase microextraction transmission mode (SPME-TM) device includes a mesh substrate that is coated with an extractive coating that includes a polymer, preferably a biocompatible polymer, and solid phase microextraction (SPME) particles having pores dimensioned to adsorb a molecule of interest from a matrix. The polymer covers the SPME particles, but still allows at least some of the analytes of interest present in the matrix to be adsorbed by the SPME particles. Non-biocompatible polymer can be used to bind the particles when non-biological samples are analyzed. An alternative device according to the present disclosure includes a mesh substrate that is coated with an extractive coating that includes a polymer that absorbs a molecule of interest from a matrix.

(30) In one exemplary method of extracting a compound of interest from a sample matrix and detecting the extracted compound, a coating on a coated mesh substrate is placed in a methanol:water solution (50:50) at least 15 minutes before extraction in order to improve the interaction between the coating surface and the analytes present in the matrix. Although this exemplary method discusses a conditioning step using a methanol:water solution, it should be understood that this conditioning step may result in better extraction with only some coatings, such as coatings that include C-18 particles, and may not improve extraction with coatings that include other particles, such as HLB particles.

(31) The conditioned coated mesh substrate is subsequently inserted in a sample matrix and extraction or enrichment of the analyte is performed by agitating the sample at high speed (e.g. vortex agitation at 3200 rpm, t1 min). The coated mesh substrate is subsequently rinsed in a vessel containing LC/MS grade water (t10 s) to remove potential at least some artefacts adhered to the coating surface. In this exemplary method, the coated mesh substrate is subsequently installed on a mesh-holder (which allows the easy and fast replacement of the SPME-TM devices), which is positioned in an automatic linear rail that places the SPME-TM device in front of the DART nozzle. As discussed above, methods according to the present disclosure may place the coated mesh substrate in front of a nozzle for a different ionization device.

(32) Sensitivity by SPME-TM can be enhanced towards an specific compound by changing: the characteristics of the mesh substrate (i.e. mesh material type, empty space diameter, consecutive hole to hole distance, and strand size); the characteristics of the coating (i.e. polymeric phase chemistry, particle size, porosity, thermal conductivity, thermal stability, and affinity for the analyte of interest); the operating parameters of the desorption device, such as gas temperature and flow, discharge voltage, grid electrode voltage, or spatial position of the mesh in relation to the ion source nozzle, in order to balance between efficient neutral generation by thermal desorption and transport into the mass spectrometer.

(33) Coated mesh substrates can be used for in vitro analysis of drug concentrations as well as for in situ analysis of contaminants, such as in a river stream. Coated mesh for in vitro analysis of biofluids can have any combination of extractive particles coated with an appropriate biocompatible coating, such as polyacrylonitrile (PAN), polyethylene glycol, polypyrrole, derivatised cellulose, polysulfone, or polyamide solution. Non-limiting examples of the coating include: a PAN/C-18 coating, a PAN/HLB coating, a PAN/RP-amide coating, a polyethylene glycol/HS-F5 coating, a derivatised cellulose/C-18 coating, a polypyrrole/C-30 coating, a polysulfone/phenyl coating and polyamide/cyano coating.

(34) A coated mesh substrate may be produced using a batch-coating process. In an exemplary batch-coating process, the coating was applied on the mesh by dipping the mesh into a vessel containing a suspension of extraction particles in a biocompatible coating solution. The desired coating area of the mesh was immersed in this solution for 15 seconds and then removed at a speed of about 0.1 to about 0.5 mm per second. Then, a flow of nitrogen of 1.5 L/min was used to remove the excess of coating slurry accumulated on the openings of the mesh. After applying one layer of coating, the coated blade was passed through a heater at an elevated temperature. In the exemplary batch-coating process, the steps noted above were repeated five times until the desired thickness was obtained. The rate of removal of the mesh substrate from the suspension of extraction particles can affect the interaction between the slurry and the mesh substrate. A removal rate of about 0.1 to about 0.5 mm/second results in desirable interactions between the slurry and the mesh substrate.

(35) In a batch-coating process, multiple thin layers of the suspension can be applied to the mesh substrate until the desired coating thickness is obtained. The advantage of applying multiple layers is that each coating layer is bonded and the coating thickness is uniform throughout the desired length on the mesh substrate. When the process parameters are controlled by automation, reproducibility between meshes can be greatly improved.

(36) The meshes can be pre-processed before the coating process in order to clean and roughen the surface. Pre-processing can be accomplished by washing with acetone, etching for 5 min in concentrated hydrochloric acid, washing the mesh with water and/or thoroughly cleaning the mesh by sonication in methanol. Prior to use, the coated mesh can be conditioned in water:methanol 50:50 wash for 30 min. Conditioning the C-18 based coatings with water or higher proportion of methanol can lead to worse reproducibility. Other coatings, however, can require only a very brief conditioning step (less than 5 min), or even none at all.

(37) In one example of a device according to the present disclosure, discussed in greater detail below, the coated mesh substrate (2.50.4 cm, where the coating is 10.4 cm, LW) is welded on a sheet (4.20.4 cm, LW) that can be constructed of any material. Preferably, the substrate used to construct the sheet is stainless steel or nitinol. A sheet of the size noted above allows the sheet to be used as a handle for manipulating the coated mesh substrate. Manipulating the handle, and not the coated mesh substrate, reduces the possibility that the coated mesh substrate is contaminated, and minimizes or prevents the contact of the analyst with the sample.

(38) One example of a batch-coating process is illustrated in FIG. 1. A non-coated mesh (10) is etched in a solution (12) of hydrochloric acid (37% by volume). The etched mesh (14) is cleaned in methanol (16). The cleaned mesh (18) is held with a temporary handle (20) and is dipped in a coating solution (22) that is stirred using a stir bar (24) to ensure the coating solution is well mixed. The coated mesh substrate (26) has a coated area (28) and a non-coated area (30). Excess coating solution is removed from the coated area (28) by flowing nitrogen (32) through the mesh. The coated mesh substrate having excess coating removed (34) is heated at 125 C. to remove solvent. The coating, nitrogen, and heating steps are repeated as desired. The dried coated mesh substrate (34) is removed from the temporary handle (20) and is attached to a support handle (36), for example through welding points (38).

(39) Experiment 1

(40) Preparation of Exemplary Devices

(41) A SPME-TM device was prepared as follows: a stainless steel mesh (7474 wires/in, wire diameter 0.004 in) with a length of 2.5 cm and width of 0.4 cm was etched for 5 min in concentrated hydrochloric acid (37% vol/vol), washed with water, and cleaned by sonication in methanol. A photograph of the etched mesh is shown in FIG. 2. The etched mesh was stored in an inert atmosphere in a desiccator in order to prevent oxidation or significant changes of surface prior to coating.

(42) A coating solution, 0.18 wt/wt PAN/C18 particles ratio and 1% wt/wt PAN/DMF ratio, was prepared. The coating solution was continuously agitated at a speed of 1000 rpm using an octagonal stir bar (124.5 mm). Coatings were applied on the strands of the mesh substrate by dipping the mesh for 15 seconds into a small vessel containing the coating solution, and the mesh was removed at a speed ranging between 0.1 to 0.5 mm/s. The actual coated area has a length of 1 cm and width of 0.4 cm. Subsequently, nitrogen was flowed through the coated mesh substrate (1.5 L min.sup.1) to dry the coating on the wires and to remove excess slurry trapped on the mesh openings. The coating was cured for about 1.5 min at 125 C.

(43) The coating process was repeated until the desired thickness was obtained. It was found that 5 or fewer cycles was enough to obtain a thin layer of coating. A photograph of the coated mesh substrate is shown in FIG. 3, and scanning electron micrographs of the coated mesh substrate are shown in FIG. 4-6.

(44) The coated mesh substrate (34) has a coated area (28) and a non-coated area (30). The non-coated area (30) was arc welded to a support handle (36) made of a stainless steel sheet that is 4.20.4 cm (LW). In order to provide a strong attachment between the mesh and the solid substrate, the mesh was welded on 6 points (as illustrated in FIG. 7). The stainless steel sheet could alternatively be fabricated of any biocompatible material, e.g. nitinol. The coated mesh could alternatively be attached or glued to other biocompatible and chemically inert material, such as Teflon or polybutylene terephthalate or a 3D printing material.

(45) Experiment 2

(46) Analytical Process for Exemplary Devices

(47) An exemplary analytical process with SPME-TM, is illustrated in FIG. 8. As illustrated in step (40), a coated mesh substrate prepared according to Experiment 1 was inserted in a vial containing a sample matrix (300-1500 L) and extraction and enrichment was performed by agitating at the sample at high speed (vortex agitation at 3200 rpm, t1 min). The coated mesh substrate was rinsed at (42) in a vial containing water (1500 L, t10 s) to remove at least some artefacts adhered to the coating surface. The coated mesh substrate was installed on a holder, which allows the easy and fast replacement of the coated mesh substrate. Then holder is positioned in an automatic linear rail that moves the mesh between the DART nozzle and the MS inlet (with all three coaxial to one-another, 0 angle). As illustrated in step (44), a metastable gas stream was flowed through the mesh performing simultaneous desorption and ionization of the compounds sorbed on the surface of the coating particles. Ions of the extracted or pre-concentrated analytes were transported into the atmospheric pressure interface (API) and analyzed by tandem mass spectrometry.

(48) FIG. 9 illustrates a holder (46) that holds 12 coated mesh substrates (34) by the support handles (36). The holder (46) holds the coated solid substrates (34) in a configuration that allows them to be inserted into one row of a 96-well plate. The holders (46) include magnets (48) that are positioned to attach one holder to an adjacent holder. The holder (46) is sized and shaped so that 8 holders attached together allow the coated solid substrates to be inserted into the 8 rows of a 96-well plate. The 8 attached holders, each holding 12 coated solid substrates, allow each of the 96 coated solid substrates to be inserted into each of the 96 wells.

(49) FIG. 10 shows and illustrates an automatic linear rail that sequentially moves each coated mesh substrate between the DART nozzle and the MS inlet.

(50) Experiment 3

(51) Detection Capabilities of Exemplary Devices

(52) It has been incorrectly assumed by scientist not familiar with SPME that extraction and enrichment cannot be performed in short periods of time. In the context of the present disclosure, a short extraction time would be understood to mean extraction times of 60 seconds or less. High surface area contact between extraction phase and the matrix facilitates high mass transfer rates. The thin coatings ensure rapid equilibration times and efficient desorption to MS instrument. Additionally, it is also assumed by scientist not familiar with SPME that extractions should be performed at equilibrium to achieve lower LOD/LOQ.

(53) Given that the dilution factor inherent in most SPME-LC methods is removed from the analytical procedure, methods and devices disclosed herein outperform traditional detection limits with remarkably brief extraction times. Hence, the LOD associated with methods and devices disclosed herein is mainly constrained by the detection capabilities of the MS system rather than by built-in features of the coating. Experiments using thin-film microextraction devices (TFME, blade geometry as illustrated in FIG. 7) showed that 15 seconds is sufficient to extract a quantifiable amount of analyte at the low ppb level even when using the traditional LC/MS approach. Results of these experiments are shown in FIG. 11. Indeed, if lower LOD are required, the interaction time between the coating and the sample matrix can be increased. For instance, LOQ as low as 2 and 19 pg mL.sup.1 were reached when performing 1 minute extraction from 1.5 mL of phosphate buffered saline (PBS) spiked with cocaine and diazepam (DZP), respectively. Furthermore, the linear dynamic range of the method, evaluated from 10 pg mL.sup.1 up to 50 ng mL.sup.1, showed astounding linearity. Results of these experiments are shown in FIGS. 12 and 13. It is worth emphasizing that higher concentration levels are not a limitation for SPME. Indeed, if there is the case in which a compound is present at high concentration (i.e. ppm levels) and the affinity of the coating for the analyte is strong, shorter extraction times (e.g. 30 s) can be performed.

(54) Experiment 4

(55) Intra- and Inter-Device Reproducibility of Exemplary Devices

(56) A unique feature of the devices disclosed in Experiment 1 in comparison with other ambient mass spectrometry devices is their reusability. Extractions performed with 9 independent devices (n=36) from 1.5 mL of PBS solution spiked with cocaine and diazepam showed intra-/inter-device reproducibility lower than 4.7 and 3.2%, respectively (Table 1-5). Certainly, herein is confirmed that by using thin-coatings not only efficient mass transfer of the analytes is achieved (fast extractions), but also effective desorption. In addition, despite that it was found that the signal obtained on a second desorption and ionization cycle (carryover) was approximately 5% of signal use for quantitation of DZP (FIG. 14A), it is important to highlight that detection of DZP and cocaine was performed concomitantly. Thus, DART experimental conditions were not exclusively optimized for DZP and this could explain why a small fraction of analyte still remained after the first desorption and ionization cycle. Nevertheless, by implementing a cleaning step shortly after the desorption and ionization cycle (i.e. mixture of methanol, isopropanol and acetonitrile; 50:25:25) negligible carry-over was attained (0.4%, FIG. 14B). The cleaning step could be optimized according to both the chemistry of the coating and its affinity towards the analyte of interest. In cases where there is an extensive variation in analyte concentration among samples (i.e. low ppt to ppm levels) devices could preferably be restricted to a single use. Otherwise, a few amount of analyte could remain on the coating, even after the cleaning cycle, and cause potential false positives. While working with compounds at concentrations greater than 50 ppb and with high affinity towards the coating, shorter extractions can be performed (30 s). Extracting with shorter extraction times reduces the amount of analyte enriched and the complete removal of the analytes that are not desorbed by DART, or other solvent or thermally based ionization approaches, is possible when including the cleaning step.

(57) TABLE-US-00001 TABLE 1 SPME-TM inter-device reproducibility. Ratio RSD % Carryover % Carryover Experiment [A/Is] SD [%] DART [A.sub.c/A.sub.i] solvent [A.sub.c/A.sub.i] Diazepam 1.8 0.05 3 5 0.3 Cocaine 1.6 0.05 3 2.4 0.2 SD, standard deviation; RSD, relative standard deviation. Ratio [Analyte/Isotopologue] results correspond to the average of extractions performed with 9 independent devices (n = 36) from a PBS solution spiked with 20 ppb of each analyte.

(58) TABLE-US-00002 TABLE 2 Inter- and intra-mesh reproducibility (n = 36). Results are reported as ratio of analyte (diazepam) versus internal standard isotopologue [D.sub.5] diazepam. 1 min extractions were performed using vortex agitator set-up at maximum speed (3200 rpm). Extraction from 1.5 mL of PBS spiked with 20 ng mL.sup.1 of each substance. Analyses were performed using Thermo TSQ on SRM mode. Experiment Mesh_1 Mesh_2 Mesh_3 Mesh_4 Mesh_5 Mesh_6 Mesh_7 Mesh_8 Mesh_9 Replicate 1 1.9 1.8 1.9 1.8 1.8 1.7 1.8 1.8 1.8 Replicate 2 1.9 1.8 1.8 1.8 1.8 1.8 1.7 1.8 1.7 Replicate 3 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 Replicate 4 1.8 1.8 1.9 1.9 1.8 1.8 1.8 1.7 1.8 Average 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 SD 0.07 0.02 0.09 0.04 0.02 0.04 0.01 0.03 0.03 RSD 3.6 1.2 4.6 2.1 1.4 2.0 0.7 1.9 1.9 SD, standard deviation. RSD, relative standard deviation.

(59) TABLE-US-00003 TABLE 3 Inter- and intra-mesh reproducibility (n = 36). Results are reported as ratio of analyte (cocaine) versus internal standard isotopologue [D.sub.3] cocaine 1 min extractions were performed using vortex agitator set-up at maximum speed (3200 rpm). Extraction from 1.5 mL of PBS spiked with 20 ng mL.sup.1 of each substance. Analyses were performed using Thermo TSQ on SRM mode. Experiment Mesh_1 Mesh_2 Mesh_3 Mesh 4 Mesh_5 Mesh_6 Mesh_7 Mesh_8 Mesh_9 Replicate 1 1.5 1.5 1.5 1.6 1.5 1.6 1.6 1.6 1.6 Replicate 2 1.5 1.5 1.6 1.6 1.6 1.6 1.6 1.6 1.6 Replicate 3 1.5 1.5 1.6 1.5 1.6 1.6 1.7 1.6 1.5 Replicate 4 1.5 1.5 1.5 1.5 1.5 1.5 1.6 1.6 1.5 Average 1.5 1.5 1.5 1.6 1.5 1.6 1.6 1.6 1.6 SD 0.03 0.02 0.05 0.04 0.07 0.03 0.04 0.04 0.05 RSD 2.1 1.0 3.3 2.8 4.7 1.7 2.2 2.8 3.3 SD, standard deviation. RSD, relative standard deviation.

(60) TABLE-US-00004 TABLE 4 Inter- and intra-mesh carry-over (n = 36). Results are reported as ratio of analyte (diazepam) versus internal standard isotopologue [D.sub.5] diazepam. 1 min extractions were performed using vortex agitator set-up at maximum speed (3200 rpm). Extraction from 1.5 mL of PBS spiked with 20 ng mL.sup.1 of each substance. Analyses were performed using Thermo TSQ on SRM mode. % Carryover % Carryover Experiment [A/Is] SD RSD DART [A2/A1] solvent [A2/A1] Replicate 1 1.8 0.06 3.2 7.2 0.5 Replicate 2 1.8 0.04 2.4 4.4 0.3 Replicate 3 1.8 0.03 1.9 4.3 0.3 Replicate 4 1.8 0.06 3.1 3.9 0.2 Average 1.8 0.05 2.7 5.0 0.3 SD, standard deviation. RSD, relative standard deviation.

(61) TABLE-US-00005 TABLE 5 Inter- and intra-mesh carry-over (n = 36). Results are reported as ratio of analyte (cocaine) versus internal standard isotopologue [D.sub.3] cocaine. 1 min extractions were performed using vortex agitator set-up at maximum speed (3200 rpm). Extraction from 1.5 mL of PBS spiked with 20 ng mL.sup.1 of each substance. Analyses were performed using Thermo TSQ on SRM mode. % Carryover % Carryover Experiment [A/Is] SD RSD DART [A2/A1] solvent [A2/A1] Replicate 1 1.6 0.05 3.4 3.1 0.5 Replicate 2 1.6 0.03 2.2 1.8 0.1 Replicate 3 1.6 0.05 3.5 2.0 0.1 Replicate 4 1.5 0.05 3.0 2.5 0.1 Average 1.6 0.05 3.2 2.4 0.2 SD, standard deviation. RSD, relative standard deviation.
Experiment 5
Application of Exemplary Devices to the Quantitation of Drugs in Complex Matrices

(62) MS analysis provides significant amounts of information about complex samples. However, sample pre-treatment required before traditional MS analysis not only is labor-intensive and time-consuming but also intricate. Due to the speed and the easiness of the analysis when using devices and methods disclosed herein, screening of controlled substances in biological samples as well as for therapeutic drug monitoring (TDM) may be performed with less labour and/or taking less time. Devices as disclosed in Experiment 1 were used for the quantification of cocaine and DZP in urine and plasma. FIGS. 15 to 18 summarize the linearity achieved in both matrices. Similar to PBS, LOQs of 2 and 5 pg mL.sup.1 were determined for cocaine in urine and plasma, respectively. Thus, matrix effects are significantly reduced by the sample clean-up provided by the disclosed methods, and analytes with low binding present comparable detection limits independently of the matrix. Because salts and biomolecules that remain mechanically attached to the coated strands during the extraction are removed through the rinsing step, the rinsing step aids to extend the operative time of the mass spectrometer by providing reliably high instrumental sensitivity as well as minimizing instrument maintenance. Unlike cocaine, the LOQ for DZP in plasma (497 pg mL.sup.1) was significantly higher in comparison to urine and PBS (19 and 28 pg mL.sup.1, respectively). However, it is worth mentioning that DZP is 98% bound to plasma proteins and devices described herein only extract the free-portion of analyte present in the matrix. Last but not least important, since the TM configuration may result in a homogeneous interaction between extracted and ionizing species, standard-free quantitation is also feasible with SPME-TM (FIGS. 19-21). Nevertheless, given that extraction is not performed at equilibrium (t1 min), precise variables should be properly controlled in order to obtain reproducible results. Such variables include: sampling time, convection (agitation speed and homogeneity of agitation), as well as coating thickness homogeneity. The first two parameters may be controlled by using automated extraction or rinsing systems. When the coating process parameters are controlled by automation, greater reproducibility between meshes can be attained.

(63) Experiment 6

(64) Analysis of Multiple Controlled Substances

(65) Nowadays multiple efforts are directed towards the development of powerful LC-MS/MS or GC-MS/MS methods that allow the analysis of controlled substances in complex matrices. Given the complexity of the components in the samples, such procedures entail cumbersome and extensive sample preparation steps. Consequently, approaches that allow fast, quantitative, and direct analysis are highly demanded. As a proof-of-concept, devices as described in Experiment 1 were used to simultaneously monitor 21 prohibited substances spiked in PBS at 20 ng mL.sup.1. Selected reaction monitoring (SRM) was used to exclusively identify each compound. LOD were tentatively predicted based on the results obtained for cocaine and diazepam in PBS (Table 6). Even though DART source parameters were not optimized for each analyte, all substances were detected and 16 compounds provided hypothetical detection limits lower than 50 pg mL.sup.1 (e.g. heroin [Log P 1.52], propranolol [Log P 3.48], and stanozolol [Log P 5.53]; FIGS. 22A-C). Insofar as methods and devices described in these Experiments derive their sensitivity and selectivity from the physicochemical properties of the exemplary extraction phase, other coatings with greater affinity towards specific target compounds can be used. Certainly, the ability to screen numerous substances in a single analysis using methods and devices described herein, without forfeiting sensitivity or quickness, is a noteworthy characteristic of this technique that could be used in other applications such as monitoring of personal care products in wastewaters or pesticides in food commodities.

(66) TABLE-US-00006 TABLE 6 MS/MS parameters used for the analysis of 21 WADA controlled substances in positive mode, as well as instrumental response of C.sub.18-PAN SPME-TM tandem mass spectrometry analysis. Integrated peak area obtained for a 20 ng mL.sup.1 solution in PBS. Average peak area (n = 3). Polarity = +. Parent Product ion Collision Average # Compound name Log P ion (m/z) (m/z) S-lenses energy peak area LOD* 1 Amphetamine 1.76 136.099 91.114 17 36 178070 112 2 Methamphetamine 2.07 150.112 91.120 19 45 984694 20 3 Nikethamide 0.33 179.100 108.102 18 76 1160349 17 4 Salbutamol 0.64 240.143 148.103 18 59 13566 1474 5 Propranolol 3.48 260.123 116.138 17 89 649034 31 6 Metoprolol 1.60 268.140 116.146 18 94 184973 108 7 Trenbolone 2.27 271.133 165.106 56 97 647916 31 8 Clenbuterol 2.61 277.068 203.049 15 70 1487480 13 9 Testosterone 3.32 289.157 97.123 21 91 1957478 10 10 Exemestane 3.70 297.173 121.118 19 72 1147042 17 11 Codeine 1.20 300.105 152.092 64 104 438727 46 12 Cocaine 2.30 304.142 182.173 18 87 10975211 2 13 Bisoprolol 2.14 326.160 116.135 17 102 441435 45 14 6-acetylmorphine 0.42 328.126 165.092 37 122 931494 21 15 Stanozolol 5.53 329.229 81.108 44 130 926273 22 16 Strychnine 1.93 335.155 184.129 36 136 604931 33 17 6-acetylcodeine 2.08 342.124 165.092 45 165 2703792 7 18 Formoterol 2.20 345.133 121.090 32 85 24071 831 19 Heroin 1.52 370.133 165.097 48 119 1574345 13 20 Toremifene 6.80 406.210 72.167 24 108 479105 42 21 GW501516 6.29 454.091 257.068 29 108 56878 352 LOD*, limit of detection estimated.

(67) In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments. However, it will be apparent to one skilled in the art that these specific details are not required. Accordingly, what has been described is merely illustrative of the application of the described embodiments and numerous modifications and variations are possible in light of the above teachings.

(68) Since the above description provides example embodiments, it will be appreciated that modifications and variations can be effected to the particular embodiments by those of skill in the art. Accordingly, the scope of the claims should not be limited by the particular embodiments set forth herein, but should be construed in a manner consistent with the specification as a whole.