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 (500µL/sample vs traditionally LLE 4mL/sample) and quickness (50min for 96 tests cycle).

Detection and quantification of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid in hair by GC/MS/MS in Negative Chemical Ionization mode (NCI) with a simple and rapid liquid/liquid extraction.

INTRODUCTION: The fine detection of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCCOOH) in hair matrix remains one of the most important topics in hair analysis. This relevance lies in the necessity to obtain evidence of effective drug consumption and dispel any doubt of environmental contamination. THCCOOH is the highest and mainly represented Δ9-THC metabolite, but its concentration in hair is very low. A sensitive method for quantitative determination of THCCOOH in hair was developed. As first step, the method was tested with different SPE/LLE conditions, but the best results were obtained with a simple ad hoc LLE extraction. The final method was fully validated, evaluating parameters like extraction recovery, linearity, specificity and sensitivity. More than one hundred hair samples were then analyzed with the validated method. Data analysis was performed so as to determine respective concentrations of the metabolite and active molecule. METHODS: Hair was washed and cut into small pieces (2-4mm). Samples (20-50mg) were spiked with deuterated internal standard (THC-d(3) and THCCOOH-d(3)) and then hydrolyzed at 90°C in 1mL of 1M NaOH for 15min. THC was isolated by a LLE basic extraction with n-hexane:ethyl acetate (9:1). Next the aqueous solution was acidified (pH 4) adding concentrated acetic acid. THCCOOH was extracted with the same mixture. Dried extracts were derivatized with pentafluoropropionic anhydride and hexafluoroisopropanol and analyzed by GC/MS/MS (Agilent 7000B triple quadrupole) in NCI mode. RESULTS: The linear range of THCCOOH is 0.1-5pg/mg, with good correlation coefficients (r(2)>0.9993). This method has great sensitivity (LOD 0.01pg/mg to LOQ 0.04pg/mg), high recovery, reproducibility and robustness. CONCLUSIONS: Based on these results, the method proved to be effective for the rapid determination of THC and THCCOOH in hair specimens.