Fully-automated systematic toxicological analysis of drugs, poisons, and metabolites in whole blood, urine, and plasma by gas chromatography–full scan mass spectrometry

Abstract

The availability of automated, rapid and reliable methods for the systematic toxicological analysis (STA) of drugs and poisons in biosamples is of great importance in clinical and forensic toxicology laboratories. Gas chromatography–continuous scan mass spectrometry (GC–MS) possesses a high potential in STA because of its selectivity and identification power. However, in order to develop a fully automated STA method based on GC–MS two main obstacles have to be overcome: (a) sample preparation is rather sophisticated owing to the need to isolate analytes from the aqueous matrix and to allow a correct GC repartition of polar analytes; (b) the large amount of information collected within a single analysis makes it difficult to isolate relevant analytical information (mass spectra of analytes) from the chemical noise. Using a bench-top GC–MS system equipped with a laboratory robot for sample preparation (the Hewlett-Packard 7686 PrepStation) and an original method for mass spectral purification, a fully automated STA procedure was developed involving isolation of drugs from the sample (whole blood with minimal pretreatment, plasma, urine) by means of solid-phase extraction, derivatization (trimethylsilylation) of the acidic–neutral and of the basic extracts, GC–MS analysis, processing of data, and reporting of results. Each step of the procedure, and the method for data analysis in particular, can be easily integrated with other existing STA methods based on GC–MS.