GC-FID optimization and validation for determination of 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxyamphetamine and methamphetamine in ecstasy tablets

Abstract

A methodology for the determination of 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxyamphetamine (MDA) and methamphetamine (MA) in seized tablets using gas chromatography with a flame ionization detector (GC-FID) is described. The chromatographic conditions, i.e. gas flow rates and temperatures for the column, injector and detector were optimized. The optimum chromatographic conditions were as follows: a CP-SIL 24 CB WCOT fused silica capillary column (30 m × 0.32 mm I.D., 0.25 μm film thickness), N2 carrier gas flowing at 2.6 mL/min, injector temperature at 290°C and detector temperature at 300°C. The oven temperature was ramped from 80°C at a rate of 20°C/min to final temperature of 270°C (1 min). All analytes were well separated within 7 min with an analysis time of 10.5 min. Calibration curves were linear over the concentration ranges of 3.125–200 μg/mL for MDMA and 6.25–200 μg/mL for MDA and MA (r > 0.990). The intra- and inter-day precisions for determining all analytes were 2.32–10.38% RSD and 1.15–9.77% RSD, respectively. The intra- and inter-day accuracies ranged from −19.79 to +17.51% DEV and −6.84 to +5.2% DEV, respectively. The lower limits of quantification (LLOQs) were 3.125 μg/mL for MDMA and 6.25 μg/mL for MDA and MA. All analytes were stable at room temperature during 24 h but significant loss occurred after 2-month storage at −20°C. The method was shown to be useful for determining the purity of MDMA in seized tablets.