Rapid and on-site analysis of amphetamine-type illicit drugs in whole blood and raw urine by slug-flow microextraction coupled with paper spray mass spectrometry

Advances in Chromatography-Free and Ambient Ionization Mass Spectrometry Techniques Toward Clinical Toxicology Testing

This review presents current scientific literature focused on chromatography-free/ambient ionization mass spectrometry techniques for clinical toxicology. Traditional methods like gas and liquid chromatography, paired with mass spectrometry, are commonly used in clinical laboratories but can be time-consuming, leading to backlogs. To alleviate workloads, immunoassays are often used for screening before confirmatory methods but are susceptible to false positives/negatives especially with structurally similar compounds. Therefore, chromatography-free ionization mass spectrometry methods could address concerns regarding uncertainty and lengthy separation. This work examines current efforts implementing these techniques along with their capabilities, limitations, and potential for future integration into clinical toxicology.

Rapid on-site detection of illicit drugs in urine using C18 pipette-tip based solid-phase extraction coupled with a miniaturized mass spectrometer

Drug abuse is a social issue worldwide, and there is an increasing demand for on-site rapid detection of illicit drugs. In this study, a rapid and simple analytical method for the detection of 6-monoacetylmorphine (6-MAM), methamphetamine (MA), methylenedioxymethamphetamine (MDMA), ketamine (K), norketamine (NK), and cocaine (COC) in urine was developed. The developed method combines C18 pipette-tip based solid-phase extraction (C18 PT-SPE) with a miniaturized mass spectrometer (miniMS), exhibiting remarkable simplicity, high sensitivity, and strong reliability, compared with the conventional method. The optimal extraction and elution conditions for C18 PT-SPE were considered as 9 and 3 aspirating-dispensing cycles, respectively. The miniMS parameters including spray voltage, isolation potential, and collision-induced dissociation energy for the detection of these six illicit drugs were optimized using a nano-electrospray ionization method. The limit of detection (LOD), limit of quantification (LOQ), linear range, and linearity for the analysis of six illicit drugs in urine with the proposed C18 PT-SPE-miniMS method were determined. Except for the LOD of K and COC was determined as 0.5 and 0.25 ng mL-1 respectively, and the LOD of 6-MAM MA, MDMA, and NK was determined as 1 ng mL-1. This method enables rapid on-site detection, providing easier operation, lower cost, and better portability compared to conventional methods, making it a potential tool in drug crime investigation and forensic science.

A simple, quick and non-destructive approach for sampling drugs of abuse in tablets and blotter for qualitative analysis by paper spray mass spectrometry

This study presents the development of a simple, fast, and inexpensive approach for the direct analysis of new psychoactive substances (NPS) in seized tablets and blotter paper, with improved sample preservation and increased analytical frequency. Paper triangles were gently rubbed against the surface of the samples containing synthetic drugs and then subjected to analysis by paper spray ionization mass spectrometry (PS-MS). Seized samples containing lysergic acid diethylamide (LSD) and several other substances from the classes of amphetamines, N-benzyl-substituted phenethylamines, synthetic cathinones, and synthetic cannabinoids, were analysed. Three types of paper were tested (filter paper, blotter paper, and synthetic paper) and several combinations of spray solvents were studied for the optimization. All samples were weighed and photographed before and after sequences of analysis in order to attest to the sample preservation. The results revealed that the approach is excellent for sample preservation, with less than 5% of mass loss even after 27 consecutive analyses. Moreover, no significant signal decreases were observed in mass spectrometry (MS) even after the experiments. It was possible to unequivocally identify illicit substances from seized samples (pills and blotter paper). By overcoming the solubilization and wet extraction process used for sample preparation, the waste was restricted to a volume of only 10 μL of solvent for the PS-MS analysis. The main advantage of our approach over existing methods is the sample preparation, which is simple and quick since the samples are just rubbed against the PS paper. This brings enormous benefits in terms of analytical frequency, economy of time and low consumption of solvents. Another important point is that the sample can remain intact for further analysis, which is crucial in forensic analysis.

Slug-Flow Microextraction Mass Spectrometry for Enhanced Detection of Analytes in Human Tear Fluids using Noninvasive Microsampling and Nanoelectrospray Ionization via a Capillary

In vivo noninvasive sampling and sensitive analysis of human tear fluids at the microliter level is an important but challenging task in investigating eye health. In this work, capillary microsampling coupled with slug-flow microextraction mass spectrometry (SFME-MS) was developed for enhanced detection of analytes in human tear fluids. As low as 1.0 μL of human tear fluid could be directly sampled using a capillary, and extraction/spray solvent was then loaded into the capillary to perform slug-flow microextraction and direct nanoelectrospray ionization (nESI) of analytes. All analytical procedures, including tear microsampling, microextraction, and ionization of analytes, were performed using a capillary. Enhanced detection of therapeutic drugs and disease biomarkers in human tear fluids was successfully demonstrated. Acceptable analytical performances including sensitivity, reproducibility, and quantitation were obtained. It is found that the use of SFME could improve the nESI-MS detection of trace analytes over 100-fold that depends on the chemical properties of analytes. Overall, this study showed that SFME-nESI-MS is a highly effective method for enhanced detection of trace analytes in tear fluids and is expected to be a potentially powerful tool in significant biological and clinical applications.

Rapid fabrication of hydrophobic/hydrophilic patterns on paper substrates for paper spray mass spectrometry

A simple, rapid chemical coating and patterning method was developed and optimized for paper-based substrates for use in paper spray mass spectrometry (PS-MS). A variety of chlorosilanes were explored for coating paper substrates, and their effectiveness in forming hydrophobic surfaces was characterized via contact angle goniometry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Trichloromethylsilane was selected as the primary coating agent because of the short time required to produce a hydrophobic surface (contact angle > 130°), as well as the ease of patterning. Patterning was performed using 3D-printed masks and an oxygen/plasma cleaner. Optimal mask thickness and oxygen/plasma cleaning parameters were determined to produce channels varying from 0.5 to 2.5 mm in width. The effectiveness of the patterned substrates for PS-MS was determined via analysis of four antiretrovirals: emtricitabine, lamivudine, efavirenz, and dolutegravir. Calibration curves were made for each antiretroviral at varying channel widths, and the limits of detection and limits of quantification for each drug were determined. These results show that this patterning method results in an average 7.2-fold improvement in sensitivity and an average 190-fold improvement in limits of detection over uncoated paper substrates in a neat matrix. In a proof-of-concept experiment, calibration curves were generated for each antiretroviral in urine. A patterned paper substrate with a 2-mm channel resulted in an average 7.4-fold improvement in sensitivity and an average 18-fold improvement in limits of detection over uncoated paper substrates.

Paper Spray Mass Spectrometry as an Effective Tool for Differentiating Coffees Based on Their Geographical Origins

With the rising trend of valuing flavor complexity of coffees, means to distinguish the properties of individual coffee sources is vital to the sustainable growth of the coffee industry. Herein, paper spray mass spectrometry (PS-MS), a simple technique with little sample preparation, was used to collect mass data from aqueous extracts of coffees from various sources. Thereafter, principal component analysis and linear discriminant analysis were used to successfully classify coffee samples (with 80-100 % accuracy) from various studies including the differentiations of Arabica and Robusta coffees, Arabica coffees from different countries, Robusta coffees from different geographical locations, and Arabica coffees from different locations within the same province in Thailand. With further insight from significant test via Fisher weight determination, this method was proved to be practical for differentiating coffees based on types and geographical origins, thus paving the way for broader applications.

Potential of desorption electrospray ionization and paper spray ionization with high-resolution mass spectrometry for the screening of sports doping agents in urine

In this work, desorption electrospray ionization and paper spray ionization both with high-resolution mass spectrometry (DESI-HRMS and PSI-HRMS) were explored for the fast and direct analysis of stimulants and diuretics in urine samples. The analysis was performed at a resolution of 70 000 FWHM (m/z 200) using a quadrupole-Orbitrap mass spectrometer in full scan acquisition mode, detecting stimulants and diuretics in positive and negative ion modes, respectively. The most critical parameters affecting the desorption and ionization efficiencies of compounds were optimized, paying particular attention to the optimization of the spray solvent for PSI-HRMS analysis and to the selection of the DESI sample substrate. For stimulants, the PSI-HRMS method performed better than DESI-HRMS, allowing the direct analysis of raw urine samples with better signal-to-noise ratios than DESI. However, results obtained for diuretics were not as satisfactory as we expected. The PSI-HRMS method was applied to the screening of 52 stimulants for doping control purposes, providing satisfactory detectability for most of them at the Minimum Reporting Level (MRL) in less than 2 minutes for each single analysis. Despite the advantages offered by the PSI-HRMS method, in this study is also included a discussion on the limitations observed because of the presence of interference for some compounds.

Amphetamine, methamphetamine, and MDMA in hair samples from a rehabilitation facility: Validation and applicability of HF-LPME-GC-MS

INTRODUCTION

It is known that drug abuse jeopardizes economic and social development. Toxicological analyses can guide prevention and treatment strategies in rehabilitation facilities. The current greatest challenge is finding easily adaptable and less costly sensitive methods that meet the principles of green chemistry. Hair, as a biological matrix, has several advantages, and its ability to detect consumption for longer periods keeping the matrix stable and unaltered stands out. This manuscript addresses the use of a miniaturized technique in an alternative matrix, by making use of a reduced amount of solvents to quantify amphetamines, aiming to guide prevention and treatment strategies in rehabilitation facilities.

METHODS

A Hollow Fiber Liquid-phase Microextraction (HF-LPME) technique for extracting amphetamines from hair samples with Gas Chromatography-Mass Spectrometry (CG-MS) was validated, adapted, and applied to ten samples from patients of a rehabilitation facility.

RESULTS

The technique proved to be sensitive, accurate, precise, and not affected by interference from the biological matrix and the linear range for the analytes was 0.2 to 20 ng mg ^-1. The three analytes were quantified in the samples analyzed. It is worth stressing that the patients were young.

CONCLUSION

The HF-LPME-GC-MS technique complied with the principles of green chemistry, and proved to be a sensitive technique, adaptable to the routine of common laboratories. Validation in the analysis phase with authentic samples, thus, showed that it can be an important tool for preventing and controlling drug addiction.

Direct adsorption sampling and ambient mass spectrometry analysis of tobacco smoke with porous paper strips

Chemical analysis of atmospheric aerosols by conventional analytical methods is usually required to perform complicated and time-consuming sample preparation processes. In recent decades, ambient ionization mass spectrometry (AI-MS) methods have been proven to be simple, rapid, and effective analytical tools for direct analysis of various complex samples. In this work, we applied porous paper filters for direct adsorptive sampling of tobacco smoke, and then the sampled paper filters were performed the emitters of the paper spray ionization (PSI) device. An auto-sampling device was made to control the generation and collection of tobacco smoke. Nicotine, the typical compound of tobacco smoke, was used to optimize the key conditions of auto-sampling. Moreover, different types of tobacco smoke were also compared with multivariate variable analysis, and the makers of tobacco smoke from different sources of tobacco smoke were investigated. By using this method, direct sampling and analysis of a single tobacco sample can be completed within minutes. Overall, our results show that PSI-MS is a powerful tool that integrates collection, extraction, ionization, and identification analytes in smoke.

Analysis of methamphetamine, methadone, tramadol, and buprenorphine in biological samples by ion mobility spectrometry after electromembrane extraction in tandem with slug flow microextraction

A novel tandem extraction method based on electromembrane extraction (EME) and slug flow microextraction (SFME) was developed for the extraction of some narcotics (methamphetamine, methadone, tramadol, and buprenorphine) from biological samples. The analytes were quantified by corona discharge-ion mobility spectrometry (CD-IMS). In this method, initially, analytes were extracted using an EME procedure (step-1). After that, the acceptor solution of the first step containing target analytes was applied in an SFME procedure (step-2) as a donor solution for further preconcentration. In the second step, analytes were extracted from an aqueous solution into an organic extractant. The optimum EME and SFME conditions were as follows: type of supported liquid membrane: 2-nitrophenyl octyl ether containing 10% v/v di-(2-ethylhexyl) phosphate, acceptor solution pH: 1.0, sample solution pH: 4.0, voltage: 248 V, extraction time: 17.5 min, tilting number of glass capillary tube: 10 times, type of the organic extractant: toluene, the concentration of NaOH solution: 400 mM. Under optimum extraction conditions, good linearity was obtained in the range of 0.50-750.0 ng/mL with coefficients of determination (r²) ≥ 0.991. The limits of detection and quantification were achieved in the range of 0.15-3.5 ng/mL and 0.50-12.0 ng/mL, respectively. The inter-day and intra-day precisions (n = 3) provided RSDs lower than 12.8% and 12.7%, respectively. Enrichment factors and extraction recoveries of the analytes were in the range of 255.7 to 505.4 and 37.6-78.3%, respectively. Comparing the EME/HPLC-UV with EME-SFME/CD-IMS showed that using the tandem extraction method improved the enrichment factors by more than 2.7 times and limits of detection and quantification by more than 15 times. Finally, this procedure was used to quantify target analytes in plasma and urine samples.

Lab-on-Paper Devices for Diagnosis of Human Diseases Using Urine Samples-A Review

In recent years, microfluidic lab-on-paper devices have emerged as a rapid and low-cost alternative to traditional laboratory tests. Additionally, they were widely considered as a promising solution for point-of-care testing (POCT) at home or regions that lack medical infrastructure and resources. This review describes important advances in microfluidic lab-on-paper diagnostics for human health monitoring and disease diagnosis over the past five years. The review commenced by explaining the choice of paper, fabrication methods, and detection techniques to realize microfluidic lab-on-paper devices. Then, the sample pretreatment procedure used to improve the detection performance of lab-on-paper devices was introduced. Furthermore, an in-depth review of lab-on-paper devices for disease measurement based on an analysis of urine samples was presented. The review concludes with the potential challenges that the future development of commercial microfluidic lab-on-paper platforms for human disease detection would face.

Recent advances in lab-on-paper diagnostic devices using blood samples

Lab-on-paper, or microfluidic paper-based analytical devices (μPADs), use paper as a substrate material, and are patterned with a system of microchannels, reaction zones and sensing elements to perform analysis and detection. The sample transfer in such devices is performed by capillary action. As a result, external driving forces are not required, and hence the size and cost of the device are significantly reduced. Lab-on-paper devices have thus attracted significant attention for point-of-care medical diagnostic purposes in recent years, particularly in less-developed regions of the world lacking medical resources and infrastructures. This review discusses the major advances in lab-on-paper technology for blood analysis and diagnosis in the past five years. The review focuses particularly on the many clinical applications of lab-on-paper devices, including diabetes diagnosis, acute myocardial infarction (AMI) detection, kidney function diagnosis, liver function diagnosis, cholesterol and triglyceride (TG) analysis, sickle-cell disease (SCD) and phenylketonuria (PKU) analysis, virus analysis, C-reactive protein (CRP) analysis, blood ion analysis, cancer factor analysis, and drug analysis. The review commences by introducing the basic transmission principles, fabrication methods, structural characteristics, detection techniques, and sample pretreatment process of modern lab-on-paper devices. A comprehensive review of the most recent applications of lab-on-paper devices to the diagnosis of common human diseases using blood samples is then presented. The review concludes with a brief summary of the main challenges and opportunities facing the lab-on-paper technology field in the coming years.

Sample preparation and instrumental methods for illicit drugs in environmental and biological samples: A review

Detection of illicit drugs in the environmental samples has been challenged as the consumption increases globally. Current review examines the recent developments and applications of sample preparation techniques for illicit drugs in solid, liquid, and gas samples. For solid samples, traditional sample preparation methods such as liquid-phase extraction, solid-phase extraction, and the ones with external energy including microwave-assisted, ultrasonic-assisted, and pressurized liquid extraction were commonly used. The sample preparation methods mainly applied for liquid samples were microextraction techniques including solid-phase microextraction, microextraction by packed sorbent, dispersive solid-phase extraction, dispersive liquid-liquid microextraction, hollow fiber-based liquid-phase microextraction, and so on. Capillary microextraction of volatiles and airborne particulate sampling were primarily utilized to extract illicit drugs from gas samples. Besides, the paper introduced recently developed instrumental techniques applied to detect illicit drugs. Liquid chromatograph mass spectrometry and gas chromatograph mass spectrometry were the most widely used methods for illicit drugs samples. In addition, the development of ambient mass spectrometry techniques, such as desorption electrospray ionization mass spectrometry and paper spray mass spectrometry, created potential for rapid in-situ analysis.

Exploring the chemical profile of designer drugs by ESI(+) and PSI(+) mass spectrometry-An approach on the fragmentation mechanisms and chemometric analysis

The consumption of design drugs, frequently known as new psychoactive substances (NPS), has increased considerably worldwide, becoming a severe issue for the responsible governmental agencies. These illicit substances can be defined as synthetic compounds produced in clandestine laboratories in order to act as analogs of schedule drugs mimetizing its chemical structure and improving its pharmacological effects while hampering the control and making regulation more complicated. In this way, the development of new methodologies for chemical analysis of NPS drugs is indispensable to determine a novel class of drugs arising from the underground market. Therefore, this work shows the use of high-resolution mass spectrometry Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) applying different ionization sources such as paper spray ionization (PSI) and electrospray ionization (ESI) in the evaluation of miscellaneous of seized drugs samples as blotter paper (n = 79) and tablet (n = 100). Also, an elucidative analysis was performed by ESI(+)MS/MS experiments, and fragmentation mechanisms were proposed to confirm the chemical structure of compounds identified. Besides, the results of ESI(+) and PSI(+)-FT-ICR MS were compared with those of GC-MS, revealing that ESI(+)MS showed greater detection efficiency among the methodologies employed in this study. Moreover, this study stands out as a guide for the chemical analysis of NPS drugs, highlighting the differences between the techniques of ESI(+)-FT-ICR MS, PSI(+)-FT-ICR MS, and GC-MS.

Fiber spray ionization mass spectrometry in forensic chemistry: A screening of drugs of abuse and direct determination of cocaine in urine

RATIONALE

Ambient mass spectrometry techniques are much required in forensic chemistry to evaluate evidence with low analytical interference, high confidence, and accuracy. However, traditional methodologies, such as paper spray ionization, have been shown to present low sensitivity in the analysis of illicit drugs from biological matrices.

METHODS

Fiber spray ionization mass spectrometry (FSI-MS) was developed using a capillary polypropylene (PP) hollow fiber. Seized samples of drugs, i.e. a tablet, blotter paper, hashish, and cocaine powder, were analyzed. Cocaine was quantified from whole urine by dipping the fiber directly into solution. FSI-MS was tested for the analysis of a sample of urine obtained from a drug abuse suspect.

RESULTS

The FSI(+) analysis showed the detection of different types of synthetic drugs in tablet and blotter paper samples, e.g. amphetamine, cathinones, phenethylamines, and opioids, while pure cocaine and different types of coca alkaloids were identified from cocaine powder with good sensitivity and high mass accuracy. The hashish analysis by FSI(-) revealed signals of cannabinoids, cannabinoid acids, and cannabinoid derivatives, detected mainly as [M - H]^- ions or chlorine adducts [M + Cl]^- . The quantification of cocaine in whole urine showed good sensitivity and precision with limits of detection and quantification of 5.16 and 17.21 ng/mL, respectively, linearity above 0.999, and relative standard deviation below 2.71%. The evaluation of seized sample of urine showed the detection of cocaine with relative ion intensity greater than 36%, as well as the metabolites benzoylecgonine and cocaethylene with a relative intensity of 1.4% and 6%, respectively.

CONCLUSIONS

The developed FSI-MS method has the potential to be applied to forensic sample evaluation as well as to determine illicit drugs from biological matrices in toxicological analysis. The use of a capillary PP fiber has advantages as an extractor agent and ionizing substrate, and also the feature of it being dipped directly into the sample, thus preserving the integrity of the sample, which makes this a very promising ambient mass spectrometry method and relevant to forensic chemistry.

Analysis of biofluids by paper spray-MS in forensic toxicology

Direct ambient ionization techniques have been developed with the aim to reduce the complexity of mass spectrometry analysis by minimizing sample preparation and chromatographic separation. In this context, paper spray-MS (PS-MS) is an innovative approach that provides faster and cheaper analysis of biofluids by the addition of the sample directly to a paper. In forensic toxicology, the analytical workflow for the detection and quantification of drugs of abuse is onerous, including sample treatment, extraction and clean up, especially regarding complex biological matrices. PS-MS allows the detection of analytes of toxicological interest in blood, plasma and urine using low sample volume. This review aims to discuss the potential use, advances and challenges of PS-MS in forensic toxicology.

Emerging trends in paper spray mass spectrometry: Microsampling, storage, direct analysis, and applications

Recent advancements in the sensitivity of chemical instrumentation have led to increased interest in the use of microsamples for translational and biomedical research. Paper substrates are by far the most widely used media for biofluid collection, and mass spectrometry is the preferred method of analysis of the resultant dried blood spot (DBS) samples. Although there have been a variety of review papers published on DBS, there has been no attempt to unify the century old DBS methodology with modern applications utilizing modified paper and paper-based microfluidics for sampling, storage, processing, and analysis. This critical review will discuss how mass spectrometry has expanded the utility of paper substrates from sample collection and storage, to direct complex mixture analysis to on-surface reaction monitoring.

Protein precipitation coupled to paper spray with a tube for one-step analysis of blood

RATIONALE

Accurate measurement of trace compounds in blood samples is important in clinical diagnosis and life science. Ambient ionization mass spectrometry, however, suffers from the matrix effect when dealing with complex samples such as blood. Therefore, it is important to reduce the matrix effects in blood samples.

METHODS

A low-cost and disposable Teflon tube was used as a platform to precipitate the protein in blood. The analytes are extracted into organic solvent, and the precipitated protein can be adsorbed by the chromatography paper inserted. Therefore, the Teflon tube after precipitation can be directly subjected to paper spray ionization mass spectrometry, achieving one-step analysis of blood.

RESULTS

High sensitivity and satisfactory stability were achieved for pharmaceuticals, acids, and endogenic metabolites in blood. The absolute signal intensities of characteristic product ions of the tested analytes were 8-20 times higher after protein precipitation than those obtained using paper spray. Detection limits and quantitative performance were evaluated for three drugs: carbamazepine, metformin, and tioconazole. In addition, the limits of detection and quantitation were improved 9-14- and 8-12-fold, respectively.

CONCLUSIONS

Protein precipitation coupled to paper spray with a tube and then to mass spectrometry was successfully achieved and applied in the one-step analysis of trace compounds in blood samples. The experimental results showed that this method was sensitive, stable, convenient, and economic for the direct analysis of blood.

Agarose hydrogel-enhanced paper spray ionization mass spectrometry for metabolite detection in raw urine

Rapid analysis of metabolites in biofluids is of great importance for disease diagnosis or new-born disease screening. Herein, we introduce an agarose hydrogel conditioning method to enhance the performance of paper spray ionization mass spectrometry. With facile and fast hydrogel conditioning, the signal intensity of therapeutic drugs spiked in urine was 5 to 15 fold higher than that in direct paper spray ionization mass spectrometry analysis. Consequently, the sensitivity of metabolites in urine was improved via hydrogel conditioning, resulting in 9 to 15 fold decrease in the possibility of detection (POD) levels. These results show that agarose hydrogel conditioning coupled with paper spray ionization mass spectrometry could serve as a facile ionization method for ambient mass spectrometry, which might be useful in fast screening of metabolites and therapeutic drugs in raw biofluids.

High-Throughput Liquid-Liquid Extractions with Nanoliter Volumes

Current methods for liquid-liquid extractions generally require microliter to milliliter volumes of solvents and sample, long equilibration times, and manual procedures. Extraction methods for samples in microfluidic systems have been limited as this tool is difficult to implement on the nanoliter or smaller scale. We have developed slug-flow nanoextraction (SFNE), a method based on droplet microfluidics that allows multiple liquid-liquid extractions to be performed simultaneously in a capillary tube, using only 5 nL of sample and extraction solvent per extraction. Each two-phase slug is segmented from the others by immiscible carrier fluid. We found rapid extractions (<5 s), partition coefficients matching those achieved at larger scale extractions, and potential to preconcentrate samples through volume manipulation. This method was used to accurately and rapidly determine octanol-water partition coefficients (Kow), determining identical Kow as the shake-flask method for acetaminophen, Kow = 2.48 ± 0.02. The measurement, along with calibration and 12 replicates, was complete within 5 min, consuming under 150 nL of solvent and sample. The method was also applied to extract analytes from complex biological samples prior to electrospray ionization-tandem mass spectrometry (ESI-MS/MS) at a rate of 6 s per sample, allowing for simultaneous determination of five different drugs spiked into human plasma, synthetic urine (SU), and artificial cerebral spinal fluid (aCSF) using ethyl acetate as the extraction phase. The signal-to-noise (S/N) for analytes improved up to 19-fold compared to direct ESI-MS of single-phase droplets (aqueous plugs segmented by carrier fluid), with limits of detection down to 7 nM (35 amol).

Simultaneous Determination of Selegiline, Desmethylselegiline, R/S-methamphetamine, and R/S-amphetamine on Dried Urine Spots by LC/MS/MS: Application to a Pharmacokinetic Study in Urine

Objective: Chiral analysis is a crucial method to differentiate selegiline intake from drug abuse. A dried urine spot (DUS) analytical method based on spotting urine samples (10 μL) onto dried spot collection cards, and followed by air-drying and extraction, was developed and validated for the determination of selegiline, desmethylselegiline, R/S-methamphetamine, and R/S-amphetamine. Methods: Methanol (0.5 mL) was found to be the ideal extraction solvent for target extraction from DUSs under orbital-horizontal stirring on a lateral shaker at 1,450 rpm for 30 min. Determinations were performed by direct electrospray ionization tandem mass spectrometry (ESI-MS/MS) under positive electrospray ionization conditions using multiple reaction monitoring mode. The chromatographic system consisted of a ChirobioticTM V2 column (2.1 × 250 mm, 5 μm) and a mobile phase of methanol containing 0.1% (v/v) glacial acetic acid and 0.02% (v/v) ammonium hydroxide. Results and conclusions: The calibration curves were linear from 50 to 5,000 ng/mL, with r > 0.995 for all analytes, imprecisions ≤ 15% and accuracies between -11.4 and 11.7%. Extraction recoveries ranged from 48.6 to 105.4% with coefficients of variation (CV) ≤ 13.7%, and matrix effects ranged from 45.4 to 104.1% with CV ≤ 10.3%. The lower limit of quantification was 50 ng/mL for each analyte. The present method is simple, rapid (accomplished in 12 min), sensitive, and validated by a pharmacokinetic study in human urine collected after a single oral administration of SG.

Rapid Detection of the Antibiotic Sulfamethazine in Pig Body Fluids by Paper Spray Mass Spectrometry

We report herein a practical method for nonlethal detection of the antibiotic sulfamethazine in pig body fluids via the combination of simple extraction and paper spray mass spectrometry (PS-MS). This method requires minimal sample preparation while still providing high sensitivities and accuracies in complex matrices including pig whole blood (LOD = 7.9 μg/L; recovery = 95.4-103.7%), pig serum (LOD = 11.5 μg/L; recovery = 103.2-106.2%), and synthetic urine (LOD = 11.2 μg/L; recovery = 99.1-103.2%). Given a known correlation between the level of sulfamethazine in body fluids and edible tissues, this method shows great promise as a practical and nonlethal solution for rapid testing of the drug, which can substantially aid managerial decision in the livestock industry.

Recent advances in microextraction procedures for determination of amphetamines in biological samples

Amphetamine and its related derivatives have stimulant and hallucinogenic properties. Illegal use of these drugs is an increasing global problem resulting in significant public health and legal problems. Deaths have been reported after intake of these drugs due to overdose. It is important to determine the type and concentration of illicit drugs in biological samples. These compounds are found in complex matrices at low concentration levels. The microextraction techniques are dominant sample preparation procedure and they are widely accepted as the most labor-intensive part of the bioanalytical process. For this purpose, a survey of recent published advances in microextraction procedures for quantification of amphetamines in biological samples found in the different databases from 2008 to date will be conducted.