Chiral drug analysis using mass spectrometric detection relevant to research and practice in clinical and forensic toxicology

Role of LC-MS/MS in hair testing for the determination of common drugs of abuse and other psychoactive drugs

Hair testing has been used in toxicological investigations for the last two decades, but only recently a remarkable extension of hair analysis to a variety of application fields was observed, besides drug abuse recognition. The dramatic improvements of LC-MS/MS instrumentation make the detection of tiny amounts of almost whatever drug in hair possible, even after single-dose intake. The progresses observed during the last 5 years in the detection of psychoactive substances in hair are reviewed herein. The literature is partitioned according to the target compounds, namely traditional drugs of abuse, new psychoactive substances and pharmaceutical psychoactive substances. The LC-MS/MS methods presented are addressed to determine a single class of drugs, with the primary aim of accurate quantitation, or to perform multiclass analysis, for rapid and effective screening protocols.

In situ aqueous derivatization as sample preparation technique for gas chromatographic determinations

The use of derivatization reactions is a common practice in analytical laboratories. Although in many cases it is tedious and time-consuming, it does offer a good alternative for the determination of analytes not compatible to gas chromatography. Many of the reactions reported in the literature occur in organic medium. However, in situ aqueous derivatization reactions, which can be performed directly in aqueous medium, offer important advantages over those mentioned above, such as no need of a previous extraction step and easy automation. Here we review the most recent developments and applications of in situ aqueous derivatization. The discussion focuses on the derivatization reactions used for the determination of alcohols and phenols, carboxylic acids, aldehydes and ketones, nitrogen-containing compounds and thiols in different aqueous matrices, such as environmental, biological and food samples. Several reactions are described for each functional group (acylation, alkylation, esterification, among others) and, in some cases, the same reagents can be used for several functional groups, such that there is an unavoidable overlap between sections. Finally, attention is also focused on the techniques used for the introduction of the derivatives formed in the aqueous medium into the chromatographic system. The implementation of in situ aqueous derivatization coupled to preconcentration techniques has permitted the enhancement of recoveries and improvements in the separation, selectivity and sensitivity of the analytical methods.