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Determination of licit and illicit drugs and metabolites in human sweat by liquid chromatography-tandem mass spectrometry

Sotom, Margaret; Bowdler, Paul; Honeychurch, Kevin C.


Margaret Sotom

Paul Bowdler


A liquid chromatography-tandem mass spectrometry screening method in sweat was developed for the simultaneous determination of three licit drugs (nicotine, paracetamol, and caffeine); four illicit drugs (cocaine, ketamine, 25I-NBOMe and methamphetamine) and two metabolites (benzoylecgonine and cotinine). Target drugs were liberated from sweat patches with pH 5 sodium acetate buffer and further purified by solid phase extraction (SPE) utilising Strata-X-Drug B cartridges. Optimal solvent constituents for SPE organic wash and elution were 70% v/v methanol in deionised water and 5% v/v ammonium hydroxide in methanol respectively. Chromatographic separation was achieved using a superficially porous particle C18 column with gradient elution, using (A) 0.1% formic acid in water and (B) acetonitrile as mobile phase constituents. Target drugs were identified using a combination of retention time, and the ion ratios for two precursor-product ion transitions for each analyte monitored in multiple reaction monitoring (MRM) mode. The method was linear for all target drugs from 1.0-150.0 ng mL−1 with corresponding limits of quantitation of 1.0 ng mL−1. Limits of detection were found to range from 0.1-0.6 ng per patch. The method was subsequently applied to the analysis of sweat samples from five male and four female participants aged 20-25 years. Sweat was collected from two areas (right forearm and left thigh) using protected layers of gauze. All eighteen patches tested positive for at least one target analyte. The results of this study not only show a multi-substance screening method was achieved but also that sweat patches can be used to indicate an individual's drug use. Therefore, they can provide an alternative non-invasive technique for forensic applications.

Journal Article Type Article
Acceptance Date Aug 1, 2023
Online Publication Date Aug 2, 2023
Publication Date Sep 7, 2023
Deposit Date Aug 12, 2023
Publicly Available Date Aug 3, 2024
Journal Analytical Methods
Print ISSN 1759-9660
Electronic ISSN 1759-9679
Publisher Royal Society of Chemistry
Peer Reviewed Peer Reviewed
Volume 15
Issue 33
Pages 4085-4093
Keywords General Engineering, General Chemical Engineering, Analytical Chemistry
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