Forensic applications of supercritical fluid chromatography – mass spectrometry

Chiral separation and quantitation of methylphenidate, ethylphenidate, and ritalinic acid in blood using supercritical fluid chromatography

Supercritical fluid chromatography (SFC) is a technique that analyzes compounds that are temperature-labile, have moderately low weight, or are chiral compounds. Methylphenidate (MPH) is a chiral compound with two chiral centers. MPH has two chiral metabolites, ethylphenidate (EPH) and ritalinic acid (RA). MPH is sold as a racemic mixture. The d-enantiomer of threo-MPH is responsible for medicinal effects. Due to the differing effects of the enantiomers, it is important to analyze the enantiomers individually to better understand their effects. This method utilizes SFCand solid-phase extraction (SPE) to separate and analyze the enantiomers of MPH, EPH, and RA in postmortem blood. The objective of this method was to assess a unique approach with SFC for enantiomeric separation of MPH, EPH, and RA. A SPE method was developed and optimized to isolate the analytes in blood and validated as fit-for-purpose following international guidelines. The linear range for MPH and EPH was 0.25-25 and 10-1000 ng/mL for RA in blood. Bias was -8.6% to 0.8%, and precision was within 15.4% for all analytes. Following method validation, this technique was applied to the analysis of 49 authentic samples previously analyzed with an achiral method. Quantitative results for RA were comparable to achiral technique, whereas there was loss of MPH and EPH over time. The l:d enantiomer ratio was calculated, and MPH demonstrated greater abundance of the d-enantiomer. This is the first known method to separate and quantify the enantiomers of all three analytes utilizing SFC and SPE.

Green Assessment of Chromatographic Methods Used for the Analysis of Four Methamphetamine Combinations with Commonly Abused Drugs

Numerous agents with anxiolytic or stimulant effects have the potential to be overused, and their misuse is associated with serious side effects. In Saudi Arabia, the estimated percentage of Saudis who abuse drugs is around 7–8% and the age range is 12–22 years. Methamphetamine, captagon, tramadol, heroin, and cannabis/cannabinoids have been proven to be the most commonly abused drugs in Saudi Arabia, with methamphetamine being at the top of the list. The present study focuses on the chromatographic analytical methods used for the analysis of methamphetamine in combination with commonly abused drugs, aiming to point out the greenest among them. These mixtures have been chosen as they are analyzed periodically and frequently in criminal evidence and forensic medicine. Therefore, the chances of hazards for analysts and the environment are high if the mixtures are not handled appropriately. This study aims to compare 23 chromatographic methods used for the analysis of methamphetamine mixtures in four major combinations, and to assess their greenness by using three greenness assessment tools, namely, NEMI, ESA and AGREE, to recommend the greenest analytical method. The NEMI results were proven to have low discriminating abilities and, accordingly, the comparisons are based on ESA and AGREE scores. The analysis results show that the safest methods with the most eco-friendly results (based on ESA and AGREE) are the GC-MS method proposed by Mohammed et al. to analyze methamphetamine and captagon mixtures (ESA = 79 and AGREE = 0.57), the UHPLC–MS-MS method proposed by Busardò et al. to analyze methamphetamine and cannabis/cannabinoid mixtures (ESA = 78 and AGREE = 0.57), the LC-MS method proposed by Herrin et al. to analyze methamphetamine and tramadol mixtures (ESA = 81 and AGREE = 0.56), and the LC-MS method proposed by Postigo-et al to analyze methamphetamine and heroin mixtures (ESA = 76 and AGREE = 0.58).

Supercritical fluid extraction-supercritical fluid chromatography of saliva: Single-quadrupole mass spectrometry monitoring of caffeine for gastric emptying studies†

Saliva is an attractive sampling matrix for measuring various endogenous and exogeneous substances but requires sample treatment prior to chromatographic analysis. Exploiting supercritical CO₂ for both extraction and chromatography simplifies sample preparation, reduces organic solvent consumption, and minimizes exposure to potentially infectious samples, but has not yet been applied to oral fluid. Here, we demonstrate the feasibility and benefits of online supercritical fluid extraction coupled to supercritical fluid chromatography and single-quadrupole mass spectrometry for monitoring the model salivary tracer caffeine. A comparison of ¹³ C- and ³² S-labeled internal standards with external standard calibration confirmed the superiority of stable isotope-labeled caffeine over nonanalogous internal standards. As proof of concept, the validated method was applied to saliva from a magnetic resonance imaging study of gastric emptying. After administration of 35 mg caffeine via ice capsule, salivary levels correlated with magnetic resonance imaging data, corroborating caffeine's usefulness as tracer of gastric emptying (R²  = 0.945). In contrast to off-line methods, online quantification required only minute amounts of organic solvents and a single manual operation prior to online bioanalysis of saliva, thus demonstrating the usefulness of CO₂ -based extraction and separation techniques for potentially infective biomatrices.

Interpol review of controlled substances 2016-2019

This review paper covers the forensic-relevant literature in controlled substances from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20Papers%202019.pdf.

Crystal Structures and Spectroscopic Characterization of Four Synthetic Cathinones: 1-(4-Chlorophenyl)-2-(Dimethylamino)Propan-1-One (N-Methyl-Clephedrone, 4-CDC), 1-(1,3-Benzodioxol-5-yl)-2-(Tert-Butylamino)Propan-1-One (tBuONE, Tertylone, MDPT), 1-(4-Fluorophenyl)-2-(Pyrrolidin-1-yl)Hexan-1-One (4F-PHP) and 2-(Ethylamino)-1-(3-Methylphenyl)Propan-1-One (3-Methyl-Ethylcathinone, 3-MEC)

Every year new synthetic cathinones are flooding the European drug market. They gain more and more popularity in place of cathinones that became illegal. Compounds from both groups, “classic” and “new” cathinones, have a similar chemical structure and, as a consequence, their psychoactive properties are not much different. Cathinone analogs were secured by the police during the search of a suspect’s apartment. The aim of this paper was to present results of analyses and identification of these synthetic cathinones. The structure of new psychoactive substances (NPS) was identified by single-crystal X-ray analysis, solution nuclear magnetic resonance (NMR), UHPLC-QQQ-MS/MS and GC-MS.

Recent applications of on-line supercritical fluid extraction coupled to advanced analytical techniques for compounds extraction and identification

In a previous review (Sánchez-Camargo et al., J. Sep. Sci. 40 (2017) 213-227), we discussed the application of on-line supercritical fluid extraction coupled to chromatographic techniques. This review includes an update of the most recent publications (from January 2016 till June 2018) on this topic, which employs advanced analytical techniques for extracting and identifying valuable analytes. Supercritical fluid extraction has been widely recognized as a green sample preparation technique, because it is efficient, environmentally friendly, powerful, and faster, offering the possibility of direct coupling to analytical instrumental techniques. Among those techniques, supercritical fluid chromatography has experienced an innovative progression in the last 10 years, and the most recent applications of supercritical fluid extraction are coupled to this advanced analytical tool. The general principles, both methodological and instrumental of on-line supercritical fluid extraction coupled to supercritical fluid chromatography are described here. Besides, applications of the mentioned coupling for analysing biological fluids, food, soil, and botanical samples are also presented and discussed. Finally, a brief description about the very recent on-line coupling of supercritical fluid extraction to ion mobility spectrometry is presented, as well as concluding remarks about the importance of using these coupled techniques in the near future.