The Determination of Cannabinoids in Urine Samples Using Microextraction by Packed Sorbent and Gas Chromatography-Mass Spectrometry.

Cannabis is the most consumed illicit drug worldwide, and its legal status is a source of concern. This study proposes a rapid procedure for the simultaneous quantification of Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-THC), 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (THC-COOH), cannabidiol (CBD), and cannabinol (CBN) in urine samples. Microextraction by packed sorbent (MEPS) was used to pre-concentrate the analytes, which were detected by gas chromatography-mass spectrometry. The procedure was previously optimized, and the final conditions were: conditioning with 50 µL methanol and 50 µL of water, sample load with two draw-eject cycles, and washing with 310 µL of 0.1% formic acid in water with 5% isopropanol; the elution was made with 35 µL of 0.1% ammonium hydroxide in methanol. This fast extraction procedure allowed quantification in the ranges of 1-400 ng/mL for THC and CBD, 5-400 ng/mL for CBN and 11-OH-THC, and 10-400 ng/mL for THC-COOH with coefficients of determination higher than 0.99. The limits of quantification and detection were between 1 and 10 ng/mL using 0.25 mL of sample. The extraction efficiencies varied between 26 and 85%. This analytical method is the first allowing the for determination of cannabinoids in urine samples using MEPS, a fast, simple, and low-cost alternative to conventional techniques.

Analysis of opiates in urine using microextraction by packed sorbent and gas Chromatography- Tandem mass spectrometry.

Opiates recreational consumption has always been a concern in society, public health, and in clinical toxicology analysis. The aim of this study was to develop and fully validate an analytical method, which was simple and rapid for the determination of tramadol, codeine, morphine, 6- acetylcodeine, 6-monoacetylmorphine and fentanyl using gas chromatography coupled to tandem mass spectrometry. The procedure includes the use of microextraction by packed sorbent for sample clean-up. A mixed mode sorbent was used, allowing the minimal use of solvents. The method was validated in urine samples, with the ability to detect and quantify all analytes with satisfactory linearity (in the range of 1 - 1000 ng/mL for all analytes, except for fentanyl (10-1000 ng/mL)). Extraction efficiency varied from 17 to 107%, which did not impair sensitivity, taking into account the low LLOQs obtained (1 ng/ mL for all analytes; and 10 ng/mL for fentanyl). The developed procedure proved to be fast, selective, and accurate for use in routine analysis, with a low volume of sample (250 µL).

Determination of amphetamine-type stimulants in urine samples using microextraction by packed sorbent and gas chromatography-mass spectrometry.

The aim of this work was the development, optimization and full validation of a method applying microextraction by packed sorbent (MEPS) coupled to gas chromatography-mass spectrometry (GC-MS) to determine amphetamine (AMP), methamphetamine (MAMP), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxyethylmethamphetamine (MDMA), 3,4-methylenedioxy-N-methyl-α-ethylfenilethylamine (MBDB), and 3,4-methylenedioxy-N-ethylamphetamine (MDE) in urine samples. Using 200 µL of sample, the MEPS procedure was optimized concerning type of sorbent, sample dilution, number of strokes, activation of the ion exchange mechanism and composition of both washing and elution solvents. The method was fully validated according to the Food and Drug Administration and the Scientific Working Group of Forensic Toxicology guidelines for the validation of bioanalytical methods. The studied parameters included selectivity, calibration model and linearity, limits of detection and quantification, precision, accuracy, stability, dilution integrity and recoveries. Linearity was obtained in the range of 25-1000 ng/mL for MAMP, MBDB and MDE, 35-1000 ng/mL for AMP and MDMA, and 50-1000 ng/mL for MDA, with coefficients of determination (R2) >0.99 for all analytes. Both intra- and inter-day precision and accuracy were adequate, and coefficients of variation lower than 15% and mean relative errors (RE) within a range of ±15% of the theoretical concentrations were obtained for all compounds under study. Analyte recoveries ranged from 19 to 71%, allowing LLOQs ≤50 ng/mL.

Determination of "new psychoactive substances" in postmortem matrices using microwave derivatization and gas chromatography-mass spectrometry.

Despite worldwide efforts aiming to ban the marketing and subsequent abuse of psychoactive substances such as synthetic cathinones and phenethylamines, there has been an alarming growth of both in recent years. Different compounds similar to those already existing are continuously appearing in the market in order to circumvent the legislation. An analytical methodology has been validated for qualitative and quantitative determinations of D-cathine (D-norpseudoehedrine), ephedrine, methcathinone, 1-(4-methoxyphenyl)-propan-2-amine (PMA), mephedrone, methedrone, 2,5-dimethoxy-4-methylamphetamine (DOM), 4-bromo-2,5-dimethoxyamphetamine (DOB), 2,5-dimethoxyphenethylamine (2C-H), 4-bromo-2,5-dimethoxyphenethylamine (2C-B), 4-iodo-2,5-dimethoxyphenethylamine (2C-I), 2-[2,5-dimethoxy-4-(ethylthio)phenyl]ethanamine (2C-T-2), 2,5-dimethoxy-4-isopropylthiophenethylamine (2C-T-4) and 2-[2,5-dimethoxy-4-(propylthio)phenyl]ethanamine (2C-T-7), in low volumes of vitreous humor (100 µL), pericardial fluid (250 µL) and whole blood (250 µL), using deutered amphetamine, ephedrine and mephedrone as internal standards. The validation parameters included selectivity, linearity and limits of detection and quantification, intra- and interday precision and trueness, recovery and stability. The method included mixed-mode solid phase extraction, followed by microwave fast derivatization and analysis by gas chromatography-mass spectrometry operated in selected ion monitoring mode. The procedure was linear between 5 and 600 ng/mL, with determination coefficients higher than 0.99 for all analytes. Intra- and interday precision ranged from 0.1 to 13.6%, while accuracy variability was within 80-120% interval from the nominal concentration at all studied levels. The extraction efficiencies ranged from 76.6 to 112.8%. Stability was considered acceptable for all compounds in the studied matrices. The developed assay was applied to authentic samples of the Laboratory of Chemistry and Forensic Toxicology, Centre Branch, of the National Institute of Legal Medicine and Forensic Sciences, Portugal.

A validated procedure for detection and quantitation of salvinorin a in pericardial fluid, vitreous humor, whole blood and plasma using solid phase extraction and gas chromatography-mass spectrometry.

The use of vitreous humor and pericardial fluid as alternative matrices to blood and plasma in the field of forensic toxicology is described to quantitate low levels of Salvinorin A using ethion as internal standard. The method was optimized and fully validated using international accepted guidelines. The developed methodology utilizes a solid phase extraction procedure coupled to gas chromatography mass spectrometry operated in the selected ion monitoring mode. The method was linear in the range of 5.0-100ng/mL with determination coefficients higher than 0.99 in 100µL of vitreous humor and in 250µL of each matrix pericardial fluid, whole blood and plasma. The limits of detection and quantitation were experimentally determined as 5.0ng/mL, intra-day precision, intermediate precision and accuracy were in conformity with the criteria normally accepted in bioanalytical method validation. The sample cleanup step presented mean efficiencies between 80 and 106% in the different biological specimens analyzed. According to the low volumes of samples used, and the low limits achieved using a single quadrupole mass spectrometer, which is available in most laboratories, we can conclude that the validated methodology is sensitive and simple and is suitable for the application in forensic toxicology laboratories for the routine analysis of Salvinorin A in both conventional and unconventional biological samples.

Hair analysis for delta(9)-THC, delta(9)-THC-COOH, CBN and CBD, by GC/MS-EI. Comparison with GC/MS-NCI for delta(9)-THC-COOH.

A sensitive analytical method was developed for quantitative analysis of delta(9)-tetrahydrocannabinol (delta(9)-THC), 11-nor-delta(9)-tetrahydrocannabinol-carboxylic acid (delta(9)-THC-COOH), cannabinol (CBN) and cannabidiol (CBD) in human hair. The identification of delta(9)-THC-COOH in hair would document Cannabis use more effectively than the detection of parent drug (delta(9)-THC) which might have come from environmental exposure. Ketamine was added to hair samples as internal standard for CBN and CBD. Ketoprofen was added to hair samples as internal standard for the other compounds. Samples were hydrolyzed with beta-glucuronidase/arylsulfatase for 2h at 40 degrees C. After cooling, samples were extracted with a liquid-liquid extraction procedure (with chloroform/isopropyl alcohol, after alkalinization, and n-hexane/ethyl acetate, after acidification), which was developed in our laboratory. The extracts were analysed before and after derivatization with pentafluoropropionic anhydride (PFPA) and pentafluoropropanol (PFPOH) using a Hewlett Packard gas chromatographer/mass spectrometer detector, in electron impact mode (GC/MS-EI). Derivatized delta(9)-THC-COOH was also analysed using a Hewlett Packard gas chromatographer/mass spectrometer detector, in negative ion chemical ionization mode (GC/MS-NCI) using methane as the reagent gas. Responses were linear ranging from 0.10 to 5.00 ng/mg hair for delta(9)-THC and CBN, 0.10-10.00 ng/mg hair for CBD, 0.01-5.00 ng/mg for delta(9)-THC-COOH (r(2)>0.99). The intra-assay precisions ranged from <0.01 to 12.40%. Extraction recoveries ranged from 80.9 to 104.0% for delta(9)-THC, 85.9-100.0% for delta(9)-THC-COOH, 76.7-95.8% for CBN and 71.0-94.0% for CBD. The analytical method was applied to 87 human hair samples, obtained from individuals who testified in court of having committed drug related crimes. Quantification of delta(9)-THC-COOH using GC/MS-NCI was found to be more convenient than GC/MS-EI. The latter may give rise to false negatives due to the detection limit.