Comparison of different chiral selectors for the enantiomeric determination of amphetamine‐type substances in human urine by solid‐phase extraction followed by capillary electrophoresis‐tandem mass spectrometry

Abstract

The present study develops a method for the enantioseparation of a group of amphetamines and their metabolites in urine by CE coupled to MS/MS (CE-MS/MS). Amphetamines present a chiral center and thus two enantiomers, which is important from a toxicological point of view because they may have different pharmacokinetic and pharmacological properties. It is therefore essential to find suitable methods to distinguish both enantiomers. Today the use of CE is becoming more important in this field since, with the simple addition of a chiral selector to the background electrolyte, the enantioseparation can easily be achieved. However, when CE is coupled to MS, the use of volatile chiral selectors and compatible background electrolytes or other strategies such as the countercurrent migration approach are required to avoid contamination of the ion source from nonvolatile species. In the present study, we use the latter strategy to evaluate six different chiral selectors using CE-MS/MS. As a sample pre-treatment, two cationic-exchange sorbents-Oasis WCX and Oasis MCX-are compared for the urine pre-treatment. Using this method, it was possible to achieve the complete chiral separation of the amphetamines under study with detection limits ranging between 0.8 and 1.5 ng/mL and method quantification limits between 2.0 and 8.0 ng/mL. Matrix-matched calibration curves up to 150 ng/mL were used to cover the usual concentration ranges at which amphetamines have generally been found in toxicological and forensic analyses.

Capillary Electrophoresis: A Three-Year Literature Review

“…The presence of nonvolatile chiral selectors in the BGEs is the main reason for this situation. Recent strategies to eliminate contamination of the ionization source with chiral selectors still mainly involve the use of partial-filling or counter-migration techniques. Alternatively, chiral capillary electrochromatography (CEC) may offer a solution by immobilizing the chiral selectors on the capillary surface or in the stationary phase .…”

Interpol Review of Drug Analysis 2019-2022

“…2019 GC/MS method for fenethylline profiling of seized samples ; LC-QTOF-MS method for the simultaneous analysis of 111 amine-based compounds belonging to ergogenics, anorectics and other active components including phenethylamines (amphetamines, ephedrines), sibutramine or yohimbine [ 475 ]; excitation-emission matrix fluorescence combined with parallel factor analysis for quantitative analysis of the ATSs illegal drugs [ 476 ]; 2020 investigation of the efficiency and effectiveness of a gas-to-liquid (GTL) extraction system for the extraction of amphetamine-type substances and their precursors from the vapor phase [ 477 ]; LC-MS/MS method for detection of the presence of synthetic amines in dietary supplements [ 478 ]; enantioselective HPLC-MS/MS method for the quantification of (R)-AMP, (S)-AMP, (R)-MA, (S)-MA, (1R,2R)-pseudoephedrine, (1S,2S)-pseudoephedrine, (1R,2S)-ephedrine, (1S,2R)-ephedrine, (1R,2S)-norephedrine, (1S,2R)-norephedrine, (R)-cathinone, (S)-cathinone, and (1S,2S)-norpseudoephedrine (cathine) [ 479 ]; 2021 review of MA and AMP detection and roadside testing [ 480 ]; determination of the variations in delta C-13 and delta N-15 values of nitrogen sources used in the clandestine production of ATSs using isotope ratio mass spectrometry [ 481 ]; electrochemiluminescence strategy for the screening of MA and AMP [ 482 ]; review of laboratory-based and portable methods for detection of ATSs [ 483 ]; review of the prevalence of ATSs in Iran [ 484 ]; SALDI-MS method for the analysis of ATSs, including MA, MDMA, MDEA, and 4-fluoromethamphetamine (4-FMA) [ 485 ]; ATS drug classification using a one-dimensional convolutional neural network model [ 486 ]; 2022 colorimetric assay for detection of ATSs in aqueous solution, spiked drinks, and ‘ecstasy’ tablets [ 487 ]; development and validation of a GC-MS method for identification and quantification of AMP, MA, MDA and MDMA [ 488 ]; development of drug screening kits for the detection of ATSs in drinks [ 489 ]; analysis of feature selection method for 3D molecular structure of ATS drugs [ 490 ]; study of the pharmacological properties of MDA analogues and two related amphetamine-based compounds (N,alpha-DEPEA and DPIA) detected in street drug samples or in sport supplements [ 491 ]; chiral analysis of AMP (n = 143), MDMA (n = 94), and MA (n = 528) in samples seized in southern Germany in 2019 and 2020 using different chromatographic methods [ 492 ]; comparison of different chiral selectors for the enantiomeric determination of amphetamine-type substances by SPE-CE-MS/MS [ 493 ]; ultrahigh performance LC-MS/MS (UPLC-MS/MS) method coupled with magnetic SPE (MSPE) for determination of ultra-trace ATSs [ 494 ]; desk review of Vietnamese national drug policy documents regarding ATSs and in-depth key informant interviews were conducted from 2019 to 2021 [ 495 …”

Strategies for capillary electrophoresis: Method development and validation for pharmaceutical and biological applications—Updated and completely revised edition

“…This concept has been extensively reviewed considering the material used [436–440] or the target analytes (i.e., parabens [441], peptides [442], natural products [443], drugs of abuse [444], pollutants [445], organic acids [435], or oligonucleotides [446]). Beyond the use of non‐specific hydrophobic (C 18 [447] or carbon‐based materials [165, 448]) or electrostatic interactions [449, 450], perhaps the most significant advancements reported involve the use of much smaller volumes (typically just a few µL) of both sample and elution [451] and the application of custom materials [452] that can give some selectivity prior to the separation. In addition, many groups have invested significant efforts into the incorporation of novel phases into cartridges (for online [453, 454]) or in‐tube [455–457] SPE.…”