Rapid screening method for determination of Ecstasy and amphetamines in urine samples using gas chromatography-chemical ionisation mass spectrometry

The need for analytical screening tests more reliable and valid to detect amphetamine and related ‘‘designer drugs’’ inbiological samples is becoming critical, due to the increasing diffusion of these drugs on the European illegal market. Themost common screening procedures based on immunoassays suffer a number of limitations, including low sensitivity, lack ofspecificity and limited number of detectable substances. This paper describes a screening method based on gas-chromatography-mass–spectrometry (GC / MS) using positive chemical ionisation (PCI) detection. Methanol was used asreactant gas in the ionisation chamber. Molecular ions of different compounds were monitored, allowing a sensitivity of5–10 ng / ml with high selectivity. The sensitivity of the method gives positive results in samples taken 48–72 h after intakeof one dose of 50–100 mg. The method is simple and rapid. Sample preparation was limited to one liquid–liquid extraction,without any hydrolysis and derivatisation. Hydrolysis is critical to identify metabolites excreted as conjugates. Blank urinesamples spiked with known amounts of amphetamine (AM), methylamphetamine (MA), methylenedioxyamphetamine(MDA), methylenedioxymethylamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA) and methylenedi-oxyphenyl-N-methyl-2-butanamine (MBDB) were analysed. The method was successfully tested on real samples of urinefrom people, whose use of amphetamine was suspected, and results were compared with results obtained withimmunoassays.