The role of miniaturized systems in analytical toxicology: new psychoactive substances

• Main Author: Moreno, Ivo Emanuel Dias
• Publication Date: 2016
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://hdl.handle.net/10400.6/4319
• topic: Substâncias psicoactivas; Substâncias psicoactivas - Microextracção em seringa empacotada; Substâncias psicoactivas - Amostras biológicas

In recent years new psychoactive substances (NPS) have emerged, sold via the Internet as licit drugs of abuse. These compounds, also called "legal highs", are designed as substitutes for illegal drugs, causing similar effects. In Portugal, as in the rest of the world, their abuse as well as their effects and consequences in the life of individuals and society, has become increasingly alarming and with great social impact, claiming more attention from health professionals. As such, due to lack of scientific information in this context, there is a clear need to provide laboratories with tools for combating this situation, by means of methods development to identify and quantify these emerging psychoactive substances. The objectives of this thesis were the development, optimization and validation of extractive and chromatographic techniques for the identification and quantification of new psychoactive drugs available in Portugal, namely salvinorin A, ketamine (K) and its major metabolite norketamine (NK) and methoxetamine (MXE) in samples of toxicological interest (plasma and urine). Gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) was the chosen chromatographic technique. Sample preparation was carried out through microextraction in packed sorbent (MEPS), and for a better efficiency of the extraction process, all parameters susceptible of influencing the procedure were optimized using a powerful statistical tool, the Design of Experiments (DOE). To verify that the analytical method was suitable for its intended purpose, it has been validated according to internationally accepted criteria. The methodologies proved to be selective, linear within the studied concentration ranges, with determination coefficients greater than 0.99 for all analytes and presenting limits of detection of 5 ng/mL for salvinorin A, K, and NK and 1 ng/mL for MXE. Under optimized conditions, recovery values ranged from 71 to 80% for salvinorin A, 73-101% for K and NK in urine and 63-89% in plasma, 80-110% and 81-88% for MXE in urine and plasma, respectively. To evaluate the applicability of the present methods, they were applied to real samples; however, none of the psychoactive substances was detected, with exception of mCPP. MEPS proved to be a fast and easy-to-use procedure for the determination of selected drugs in urine and plasma samples, reducing costs and time of analysis. Furthermore, the use of reduced volumes of biological sample makes the method a valuable tool for the determination of the studied compounds, for example in situations of clinical and forensic context.