Highly sensitive analysis of methamphetamine and amphetamine in human whole blood using headspace solid-phase microextraction and gas chromatography-mass spectrometry

SERS and machine learning based effective feature extraction for detection and identification of amphetamine analogs

Surface-enhanced Raman spectroscopy (SERS) is extensively researched in diverse disciplines due to its sensitivity and non-destructive nature. It is particularly considered a potential and promising technology for rapid on-site screening in drug detection. In this investigation, a technique was developed for fabricating nanocrystals of Ag@Au SNCs. Ag@Au SNCs, as the basic material of SERS, can detect amphetamine at concentrations as low as 1 μg/mL. The Ag@Au SNCs exhibits a strong surface plasmon resonance effect, which amplifies molecular signals. The SERS spectra of ten substances, including amphetamine and its analogs, showed a strong peak signal. To establish a qualitative distinction, we examined the Raman spectra and conducted density functional theory (DFT) calculations on the ten aforementioned species. The DFT calculation enabled us to determine the vibrational frequency and assign normal modes, thereby facilitating the qualitative differentiation of amphetamines and its analogs. Furthermore, the SERS spectrum of the ten mentioned substances was analysed using the support vector machine learning algorithm, which yielded a discrimination accuracy of 98.0 %.

Urinary bio-monitoring of amphetamine derivatives by needle trap device packed with the zirconium-based metal-organic framework

In this research, zirconium-based metal–organic framework was utilized as a novel and efficient porous adsorbent for headspace extraction of Amphetamine, Methamphetamine, and Fenfluramine from the urine samples by a needle trap device (NTD). The Zr-UiO-66-PDC was electrosynthesized at the green conditions and characterized by various analyses such as FT-IR, XRD, FE-SEM, EDS, and elemental mapping techniques. Then, the effective parameters on the NTD efficiency such as salt content, pH, extraction/desorption temperature and time were evaluated and optimized by response surface methodology. The optimal extraction of amphetamine compounds was accomplished in 50 min at 70 ºC at the situation with NaCl content of 27% and pH: 11.90. The limit of detection, and limit of quantification factors were determined to be 0.06–0.09 and 0.5–0.8 ng mL⁻¹, respectively. Furthermore, the precision and accuracy (intra- and inter-day) of the employed procedure in the term of relative standard deviation (RSD) were calculated in the range of 8.0–9.0% and 6.8–9.8%, respectively. Also, the recovery percent of the extracted analytes were concluded in the range of 95.0–97.0% after 10 days from the sampling and storage at 4 °C. Finally, the proposed procedure was involved in the analysis of amphetamine compounds in the real urine samples. These results were proved the proposed Zr-UiO-66-PDC@HS-NTD technique coupled with GC-FID can be used as an eco-friendly, fast-response, sensitive, and efficient drug test procedure for trace analysis of the amphetamine compounds in urine samples.

A Systematic Review of Solid-Phase Microextraction Applications in the Forensic Context

Since the introduction in 1990, the solid-phase microextraction (SPME) technology has brought significant progress in many fields of forensic sciences due to the versatility of this fast and solventless alternative to conventional extraction techniques. A systematic review about SPME applications in forensic context from January 1995 to June 2018 was carried out according to systematic review guidelines. The majority of the reviewed articles (40/133) aimed to identify drugs (cannabinoids, cocaine, opiates, amphetamines, simultaneous detection of different drugs of abuse, prescribed drugs); 29 of the 133 articles focused on the investigation of fatalities; 28 of the 133 papers used headspace SPME technique for the identification of markers of chronic alcohol abuse. Sixteen papers involved this technique for the isolation of volatile organic compounds for the human odor profile and 20 concerned forensic applications regarding living people. Solid-phase microextraction was preferably employed in the headspace mode and many kinds of fibers were employed, although polydimethylsiloxane was the most adaptable to many forensic realities. Gas chromatography/mass spectrometry was more frequently used, probably for the well-established coupling with SPME. Most of the papers validated their method to harmonize the scientific approaches of procedures development. Good outcomes are reported on biological material collected from living people as well as on cadaveric samples. The results obtained by most of the studies about alcohol biomarkers on scalp hair have been adopted by the "Society of Hair Testing" to demonstrate abstinence over a pre-defined time period and to assess chronic excessive alcohol consumption.

Green sample preparations for the bioanalysis of drugs of abuse in complex matrices

The sample preparation is the most critical step involved in the bioanalytical process. When dealing with green analytical chemistry, sample preparation can be even more challenging. To fit the green analytical chemistry principles, efforts should be made toward the elimination or reduction of the use of toxic reagents and solvents, minimization of energy consumption and increased operator safety. The simplest sample preparations are more appropriate for liquid biological matrices with little interfering compounds such as urine, plasma and oral fluid. The same does not usually occur with complex matrices that require more laborious procedures. The present review discusses green analytical approaches for the analyses of drugs of abuse in complex biological matrices, such as whole blood, breast milk, meconium and hair.

Aptamer-modified carbon nanomaterial based sorption coupled to paper spray ion mobility spectrometry for highly sensitive and selective determination of methamphetamine

A cellulose paper was modified with an aptamer against methamphetamine on either carbon dots (CDs) or on multichannel carbon nanotubes (CNTs). The resulting sorbent was applied to the extraction of METH from blood or saliva. The METH-loaded paper than also was directly applied as a paper spray ionization source in ion mobility spectrometry. The carbon nanomaterial enhances sensitivity, and the aptamer enhances selectivity. The materials were covalently bound to the paper on one side, while the aptamer was immobilized on the other. After optimization of the extraction process and instrumental parameters, the limits of detection when using the aptamer-CNT modified paper are 0.6 ng·mL^-1 for saliva, and 0.45 ng·mL^-1 for plasma. The respective values when using aptamer-CD modified paper are 1.5 ng·mL^-1 for saliva and 0.9 ng·mL^-1 for plasma. Calibration plots are linear in the 2 to 150 ng·mL^-1 METH concentration range for saliva, and in the 1.5 to 200 ng·mL^-1 concentration ranges for blood when using the aptamer-CNT based method. When using the aptamer-CDs, the dynamic ranges extend from 5 to 200 ng·mL^-1 and from 3 to 250 ng·mL^-1, respectively. The method was applied to the determination of METH in real samples of saliva and blood, and the accuracy of the method was confirmed by comparison of the results with data analyzed by GC-MS. Graphical abstract ᅟ.

G-quadruplex–hemin DNAzyme molecular beacon probe for the detection of methamphetamine

In this work, a simple, cost-effective, and label-free biosensor was constructed for methamphetamine (METH) detection.

Simultaneous analysis of amphetamine-type stimulants in plasma by solid-phase microextraction and gas chromatography-mass spectrometry

Brazil is considered one of the countries with the highest number of amphetamine-type stimulant (ATS) users worldwide, mainly diethylpropion (DIE) and fenproporex (FEN). The use of ATS is mostly linked to diverted prescription stimulants and this misuse is widely associated with (ab)use by drivers. A validated method was developed for the simultaneous analysis of amphetamine (AMP), DIE and FEN in plasma samples employing direct immersion-solid-phase microextraction, and gas chromatographic/mass spectrometric analysis. Trichloroacetic acid 10% was used for plasma deproteinization. In situ derivatization with propylchloroformate was employed. The linear range of the method covered from 5.0 to 100 ng/mL. The detection limits were 1.0 (AMP), 1.5 (DIE) and 2.0 ng/mL (FEN). The accuracy assessment of the control samples was within 85.58-108.33% of the target plasma concentrations. Recoveries ranged from 46.35 to 84.46% and precision was <15% of the value of relative standard deviation. This method is appropriate for screening and confirmation in plasma forensic toxicology analyses of these basic drugs.

Analysis of Salvinorin A in plants, water, and urine using solid-phase microextraction-comprehensive two-dimensional gas chromatography-time of flight mass spectrometry

Salvinorin A, a psychoactive hallucinogen, and related compounds, were analyzed in plants, water, and urine using liquid-liquid extraction (LLE), solid-phase microextraction (SPME) and comprehensive two-dimensional gas chromatography-time of flight mass spectrometry (GC×GC-ToFMS). A semi-qualitative study of the extraction of Salvinorin A and analogs from Salvia divinorum plants by LLE showed ppb levels of Salvinorin A and several analogs in the leaves and stems of S. divinorum plants, much lower than expected. Quantitative analysis of Salvinorin A spiked into water and urine showed much better figures of merit for SPME than LLE, with limit of detection of about 5 ng/mL, linear range from 8 to 500 ng/mL and precision about ±10% for the SPME-based analyses using external standard quantitation. GC×GC-ToFMS was especially effective in separating the peaks of interest from matrix and chromatographic interferences.

Determination of different recreational drugs in hair by HS-SPME and GC/MS

A simple procedure combining headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC/MS) to detect and quantify amphetamines, ketamine, methadone, cocaine, cocaethylene and Delta(9)-tetrahydrocannabinol (THC) in hair is described. This procedure allows, in a single sample, even scant, analysis of drugs requiring different analytical conditions. A hair sample (10 mg) is washed and subjected to acidic hydrolysis. Then the HS-SPME is carried out (10 min at 90 degrees C) for amphetamines, ketamine, methadone, cocaine and cocaethylene. For derivatization of analytes, the fibre is introduced into the headspace of another closed vial containing acetic anhydride. After a chromatographic run, an alkaline hydrolysis for THC analysis is carried out in the same vial containing the hair sample previously used. For adsorption, the solid-phase microextraction needle is inserted into the headspace of the vial and the fibre is exposed for 30 min at 150 degrees C. For derivatization of analytes, the fibre is introduced into the headspace of another closed vial containing N-methyl-N-(trimethylsilyl)trifluoroacetamide. The GC/MS parameters were the same for both chromatographic runs. The linearity was proved to be between 0.01 and 10.00 ng/mg. The repeatability (intra- and interday precision) was below 10% as the coefficient of variation for all compounds. The accuracy, as the relative recovery, was 96.2-103.5% (spiked samples) and 88.6-101.7% (quality control sample). The limit of detection ranged from 0.01 to 0.12 ng/mg, and the limit of quantification ranged from 0.02 to 0.37 ng/mg. Application of the procedure to real hair samples is described. To the best of our knowledge, the proposed procedure combining HS-SPME and GC/MS is the first one be to successfully applied to the simultaneous determination of most of the common recreational drugs, including THC, in a single hair sample.

Preparation of ionic liquid based solid-phase microextraction fiber and its application to forensic determination of methamphetamine and amphetamine in human urine

A new solid-phase microextraction (SPME) procedure using an ionic liquid (IL) has been developed. Reusable IL-based SPME fiber was prepared for the first time by fixing IL through cross-linkage of IL impregnated silicone elastomer on the surface of a fused silica fiber. 1-Ethoxyethyl-3-methylimidazloium bis(trifluoromethane) sulfonylimide ([EeMim][NTf(2)]) ionic liquid was employed as a demonstration and the prepared fiber was applied to the forensic headspace determination of methamphetamine (MAP) and amphetamine (AP) in human urine samples. Important extraction parameters including the concentration of salt and base in sample matrix, extraction temperature and extraction time were investigated and optimized. Combined with gas chromatography/mass spectrometry (GC/MS) working in selected ion monitoring (SIM) mode, the new method showed good linearity in the range of 20-1500 microg L(-1), good repeatability (RSD<7.5% for MAP, and <11.5% for AP, n=6), and low detection limits (0.1 microg L(-1) for MAP and 0.5 microg L(-1) for AP). Feasibility of the method was evaluated by analyzing human urine samples. Although IL-based SPME is still at the beginning of its development stage, the results obtained by this work showed that it is a promising simple, fast and sensitive sample preparation method.

Pipette tip solid-phase extraction and gas chromatography – mass spectrometry for the determination of methamphetamine and amphetamine in human whole blood

Methamphetamine and amphetamine were extracted from human whole blood samples using pipette tip solid-phase extraction (SPE) with MonoTip C(18) tips, on which C(18)-bonded monolithic silica gel was fixed. Human whole blood (0.1 mL) containing methamphetamine and amphetamine, with N-methylbenzylamine as an internal standard, was mixed with 0.4 mL of distilled water and 50 microL of 5 M sodium hydroxide solution. After centrifugation, the supernatant was extracted to the C(18) phase of the tip (pipette tip volume, 200 microL) by 25 repeated aspirating/dispensing cycles using a manual micropipettor. Analytes retained in the C(18) phase were eluted with methanol by five repeated aspirating/dispensing cycles. After derivatization with trifluoroacetic anhydride, analytes were measured by gas chromatography - mass spectrometry with selected ion monitoring in the positive-ion electron impact mode. Recoveries of methamphetamine and amphetamine spiked into whole blood were more than 87.6 and 81.7%, respectively. Regression equations for methamphetamine and amphetamine showed excellent linearity in the range of 0.5-100 ng/0.1 mL. The limits of detection for methamphetamine and amphetamine were 0.15 and 0.11 ng/0.1 mL, respectively. Intra- and interday coefficients of variation for both stimulants were not greater than 9.6 and 13.8%, respectively. The determination of methamphetamine and amphetamine in autopsy whole blood samples is presented, and was shown to validate the present methodology.

Application of solid-phase microextraction in analytical toxicology

Solid-phase microextraction (SPME) is a miniaturized and solvent-free sample preparation technique for chromatographic-spectrometric analysis by which the analytes are extracted from a gaseous or liquid sample by absorption in, or adsorption on, a thin polymer coating fixed to the solid surface of a fiber, inside an injection needle or inside a capillary. In this paper, the present state of practical performance and of applications of SPME to the analysis of blood, urine, oral fluid and hair in clinical and forensic toxicology is reviewed. The commercial coatings for fibers or needles have not essentially changed for many years, but there are interesting laboratory developments, such as conductive polypyrrole coatings for electrochemically controlled SPME of anions or cations and coatings with restricted-access properties for direct extraction from whole blood or immunoaffinity SPME. In-tube SPME uses segments of commercial gas chromatography (GC) capillaries for highly efficient extraction by repeated aspiration-ejection cycles of the liquid sample. It can be easily automated in combination with liquid chromatography but, as it is very sensitive to capillary plugging, it requires completely homogeneous liquid samples. In contrast, fiber-based SPME has not yet been performed automatically in combination with high-performance liquid chromatography. The headspace extractions on fibers or needles (solid-phase dynamic extraction) combined with GC methods are the most advantageous versions of SPME because of very pure extracts and the availability of automatic samplers. Surprisingly, substances with quite high boiling points, such as tricyclic antidepressants or phenothiazines, can be measured by headspace SPME from aqueous samples. The applicability and sensitivity of SPME was essentially extended by in-sample or on-fiber derivatization. The different modes of SPME were applied to analysis of solvents and inhalation narcotics, amphetamines, cocaine and metabolites, cannabinoids, methadone and other opioids, fatty acid ethyl esters as alcohol markers, gamma-hydroxybutyric acid, benzodiazepines, various other therapeutic drugs, pesticides, chemical warfare agents, cyanide, sulfide and metal ions. In general, SPME is routinely used in optimized methods for specific analytes. However, it was shown that it also has some capacity for a general screening by direct immersion into urine samples and for pesticides and other semivolatile substance in the headspace mode.

Automated analysis of 2-methyl-3-furanthiol and 3-mercaptohexyl acetate at ngL−1 level by headspace solid-phase microextracion with on-fibre derivatisation and gas chromatography–negative chemical ionization mass spectrometric determination

A fast and automated method for the analysis at ng L(-1) level of aroma-powerful polyfunctional thiols has been developed and applied to wine. The sample is just poured in a 20 mL vial and its vapour extracted with a poly(dimethylsiloxane)-divinylbenzene (PDMS-DVB) solid-phase microextraction fibre (65 microm thickness) previously exposed to vapours of the reactive (pentafluorobenzyl bromide) and of an alkali (tributylamine). The derivatised compounds are subsequently desorbed in the GC system and determined by negative chemical ionization mass spectrometry. The method is fully automated by using a Combi-Pal autosampler conveniently programmed. The analysis takes 50 min, which contrasts to the long and tedious methods previously proposed. The development of an optimal procedure is constrained by the aggressive character of the reagent (towards the fibre and the chromatographic column), its volatility and the quality of the blanks that can be obtained. Therefore, a critical step was fixing in the fibre a "safe" and repetitive amount of reagent. This was achieved by exposing the fibre (5 min) to the vapours of a water:acetone (9:1) solution containing 200mg L(-1) of reagent. Under these conditions, the extraction-derivatisation of analytes improves with time and temperature, and the best working conditions are dictated by a compromise between sensitivity, speed and chromatographic performance. Although analytes studied were 2-methyl-3-furanthiol, 4-mercapto-4-methyl-2-pentanone, 3-mercaptohexanol, 2-furanmethanethiol and 3-mercaptohexyl acetate, a good analytical performance could be achieved only for these two last compounds. Both of them can be repetitively (10%<RSD<20%) determined in wine at concentrations below 0.1 ng L(-1). Other aspects considered in the method setup were the oxidation of analytes during the process, and the electron-capture detection (ECD) and MS properties of the pentafluorobenzyl derivatives of different polyfunctional thiols.

Rapid and simple method for direct determination of several amphetamines in seized tablets by GC–FID

A simple and rapid method for direct simultaneous determination of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA) and N-methyl-1-(3,4-methylenedioxyphenyl)-2-butanamine (MBDB) in seized tablets was developed using gas chromatography with flame ionization detection. Separation of all six underivatized amphetamines, including diphenylamine as internal standard, was performed in about 6 min, using SPB-50 capillary column. Amphetamine and methamphetamine eluted with negligible tailing while the other amphetamines had highly symmetrical peaks. Sensitivity per component on-column was in the nanogram range, and reproducibility from 2.6 to 6.6% at low concentration (2.4 microg/mL) and from 1.2 to 2.6% at high (70 microg/mL) concentration. The method has a wide linear range, from Limit of detection (LOD) to almost 200 microg/mL, thus allowing analysis of different samples across a wide range of possible concentrations of amphetamines. This simple, fast and precise method using gas chromatography--flame ionization detector (GC--FID), in conjunction with other methods (TLC, IR, HPLC), can be used for identification of amphetamines and direct determination in seized tablets, especially in laboratories with heavy workload.

Application of solid-phase microextraction combined with derivatization to the determination of amphetamines by liquid chromatography

This work evaluates the utility of solid-phase microextraction (SPME) in the analysis of amphetamines by liquid chromatography (LC) after chemical derivatization of the analytes. Two approaches have been tested and compared, SPME followed by on-fiber derivatization of the extracted amphetamines, and solution derivatization followed by SPME of the derivatives formed. Both methods have been applied to measure amphetamine (AP), methamphetamine (MA), and 3,4-methylenedioxymethamphetamine (MDMA), using the fluorogenic reagent 9-fluorenylmethyl chloroformate (FMOC) and carbowax-templated resin (CW-TR)-coated fibers. Data on the application of the proposed methods for the analysis of different kind of samples are presented. When analyzing aqueous solutions of the analytes, both approaches gave similar analytical performance, but the sensitivity attainable with the solution derivatization/SPME method was better. The efficiencies observed when processing spiked urine samples by the SPME/on-fiber derivatization approach were very low. This was because the extraction of matrix components into the fiber coating prevented the extraction of the reagent. In contrast, the efficiencies obtained for spiked urine samples by the solution derivatization/SPME approach were similar to those obtained for aqueous samples. Therefore, the later method would be the method of choice for the quantification of amphetamines in urine.

Preparation and usage of a new solid phase micro-extraction membrane

Liquid-liquid or solid phase extraction methods are widely used for isolating analytes from urine, blood and other samples. But the preparation procedures of the samples are laborious, intensive, and costly. In addition, the organic solvents used are toxic to both the human body and the environment. An accurate, simple and rapid method for analysis of some compounds is required for forensic, judicial, and clinical purposes. Solid phase micro-extraction membrane (SPMEM) is a new, simple and solventless preparation technique. It integrates sampling, extraction and concentration into a single step and has the advantages of both the solid phase micro-extraction (SPME) and membrane separation. In this paper, a new kind of membrane used for the solid phase micro-extraction was prepared with amide compounds. The extraction conditions such as adsorption time, desorption solvents, methods and time are studied and optimized. The dichlorvos in the blood, morphine and phenobarbital in the urine were perfectly separated by using this solid phase micro-extraction membrane, and were tested by gas chromatograph-mass spectrometer (GC-MS). All the data were acquired in scan mode except that of morphine which was obtained in a selected ion monitoring (SIM) mode. Ions used for identification were those with m/z 57, 115, 162, 215, 285.

Position of chromatographic techniques in screening for detection of drugs or poisons in clinical and forensic toxicology and/or doping control

This paper reviews chromatographic screening procedures for simultaneous detection of several drug classes relevant to clinical and forensic toxicology or doping control in urine or blood using gas chromatography-mass spectrometry (GC-MS), liquid chromatography coupled with a diode-array detector (LC-DAD) or a mass spectrometer (LC-MS). The pros and cons of the different techniques and procedures are discussed leading to the following conclusions and perspectives. GC-MS, especially in the electron ionization full-scan mode, is still the method of choice for comprehensive screening providing best separation power, specificity and universality, although requiring derivatization. LC-DAD is also often used for screening, but its separation power and its specificity are still inferior to those of GC-MS. Finally, LC-MS has shown to be an ideal supplement, especially for the detection of more polar, thermolabile and/or low-dose drugs, especially in blood plasma. It may become the gold standard in clinical and forensic toxicology and doping control if, at a later date, the costs of the apparatus will be markedly reduced, the current disadvantages like irreproducibility of fragmentation, reduction of ionization by matrix, etc. will be overcome, and finally if one of the increasing number of quite different techniques will become the apparatus standard.

Automated headspace solid-phase microextraction and capillary gas chromatography analysis of ethanol in postmortem specimens

Solid-phase microextraction (SPME) is a relatively new solventless sample preparation technique that allows simultaneous sampling, extraction, pre-concentration, and introduction of analytes from a sample matrix in a single procedure. This methodology has been used for the analysis of several drugs of forensic toxicology interest including volatile compounds. This paper describes a methodology for analysis of ethanol and other volatile compounds using automatic headspace solid-phase microextraction (HS-SPME) and capillary gas chromatography in postmortem specimens. The methodology was initially developed using standard solutions of acetaldehyde, acetone, methanol, and ethanol. Isobutanol was used as internal standard. Postmortem samples of blood, urine, and vitreous humor were obtained during medico-legal autopsies. To date, there are no published paper regarding alcohol analysis in vitreous humor specimens using HS-SPME and limited literature analyzing blood and urine samples. HS-SPME analysis showed that, under optimized conditions, ethanol and isobutanol (internal standard) were well-separated from other volatile compounds such as acetaldehyde, acetone, and methanol considered to be potential interferents in ethanol analysis. The calibration curves for each volatile compound demonstrated good linearity throughout the concentration range from 0.001 to 1.0 g/dl and the detection limit of ethanol in the studied specimens was approximately 0.0001 g/dl.

Quantitation of amphetamine, methamphetamine, and their methylenedioxy derivatives in urine by solid-phase microextraction coupled with electrospray ionization-high-field asymmetric waveform ion mobility spectrometry-mass spectrometry

Amphetamine, methamphetamine, and their methylenedioxy derivatives have been identified and measured in a human urine matrix using solid-phase microextraction (SPME) and high-field asymmetric waveform ion mobility spectrometry (FAIMS) in combination with electrospray ionization (ESI) and mass spectrometric detection (MS). Limits of detection in human urine between 200 pg/mL and 7.5 ng/mL have been achieved. The use of a simple extraction method, SPME, combined with the high sensitivity and selectivity of ESI-FAIMS-MS eliminates the need for chromatographic separation and allows for very rapid sample processing.

Current awareness. Current literature in mass spectrometry

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of mass spectrometry. Each bibliography is divided into 11 sections: 1 Books, Reviews & Symposia; 2 Instrumental Techniques & Methods; 3 Gas Phase Ion Chemistry; 4 Biology/Biochemistry: Amino Acids, Peptides & Proteins; Carbohydrates; Lipids; Nucleic Acids; 5 Pharmacology/Toxicology; 6 Natural Products; 7 Analysis of Organic Compounds; 8 Analysis of Inorganics/Organometallics; 9 Surface Analysis; 10 Environmental Analysis; 11 Elemental Analysis. Within each section, articles are listed in alphabetical order with respect to author (3 Weeks journals - Search completed at 7th. Mar. 2001)