Enzymatic digestion and selective quantification of underivatised delta-9-tetrahydrocannabinol and cocaine in human hair using gas chromatography-mass spectrometry.

Salah Eddine Breidi,James Barker,Declan P Naughton,Andrea Petróczi

doi:10.1155/2012/907893

Salah Eddine Breidi, James Barker + Show 2 more

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https://doi.org/10.1155/2012/907893

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Abstract

Gas chromatography-mass spectrometric (GC-MS) methods for drug analysis routinely employ derivatising reagents. The aim of this paper was to develop a method for the analysis of two recreational drugs, delta-9-tetrahydrocannabinol (Δ9-THC) and cocaine in hair samples using GC-MS, without prior derivatisation, thus allowing the sample to be reanalysed in its original form. An enzymatic digestion technique was also developed. Ten hair samples, that were known positive for either Δ9-THC and/or cocaine, were enzymatically digested, extracted, and then analysed by GC-MS. All samples measured contained Δ9-THC and one sample contained cocaine. The limits of detection (LOD) and quantification (LOQ) were 0.02 ng/mg and 0.05 ng/mg, respectively, for cocaine and 0.015 ng/mg and 0.02 ng/mg, respectively, for Δ9-THC. The wide detection window, ease of direct analysis by GC-MS, lower detection limits of underivatised samples, and the stability of drugs using this technique may offer an improved method of analysis.

Highlights

The United Nation’s Office on Drugs and Crimes (UNODC) and the World Health Organisation (WHO) recently estimated that 149–272 million people used psychoactive substances at least once in the past 12 months [1, 2]
We report lower limits of detection for Δ9THC and cocaine for the first time without derivatisation
The calibration curves were prepared by spiking known concentrations of Δ9-THC or cocaine to blank hair samples at 0.02, 0.05, 0.10, 0.50, 1.00, and 1.50 ng/mg, with a constant amount of Δ9-THC-D3 and cocaine-D3 (1 ng/mg)

Summary

Introduction

The United Nation’s Office on Drugs and Crimes (UNODC) and the World Health Organisation (WHO) recently estimated that 149–272 million people used psychoactive substances at least once in the past 12 months [1, 2]. The specific reasons behind the need for detection range from current risk to self and others, to future noncompliance [5]. Authorities often require evidence of abstinence from drugs before regranting driving licence [6, 7], allowing child custody [8], returning to workplace [9, 10], or licensing to practice [11]. In these cases, the detection window stretches beyond the most recent consumption. Other considerations include the accuracy, reproducibility, sample quantity required, and limits of detection/quantification for a developed method

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