Automated fast procedure for the simultaneous extraction of hair sample performed with an automated workstation

Introduction: Hair testing has a leading role in toxicology practice and even more in those aspects tightly linked to the assessment of psychoactive drug use and abuse in social life. Aim: The objective of the present study was to develop and validate an automated SPE sample-preparation step, suited for GC/MS confirmation analysis of basic drugs in hair drug control. The method was studied and optimized for quantitative determination and in a second time it was extended to real hair samples. The purpose of method validation was to ensure good reliability, reproducibility and quickness. Methods: Janus Automated Workstation (PerkinElmer) was employed to perform SPE hair extraction, using 96-well plate SPEC MP1 acquired from Varian (Agilent Technologies). After derivatization of dried extracts, screening confirmations were performed using gas chromatography (GC) followed by mass spectrometry (MS). GC/MS data were validated following standard guidelines, but our attention was focused on three headings: samples cross-contamination, "memory effect" and extraction recovery. Results: Validation requests were fully accomplished and we always obtained best results with the automated procedure. For instance, analytes mean recovery was between 70 and 90% and data analysis proved that no contamination between samples occurred. Conclusions: The automated workstation has shown good reliability (cross contamination and "memory effect" were tested and excluded), effectiveness (no false negative was detected), solvent saving (500 mu L/sample vs traditionally LLE 4 mL/sample) and quickness (50 min for 96 tests cycle). (C) 2011 Elsevier Ireland Ltd. All rights reserved.