Simultaneous determination of amphetamines and amphetamine-derived designer drugs in human urine by GC-MS.

OBJECTIVES: The purpose of this study is to evaluate the gas chromatographicmass spectrometric method (GC-MS) for assay of stimulants of amphetamine type: amphetamine (AMP), methamphetamine (MAMP), ephedrine (EPH), norephedrine (NOREPH), and the amphetamine-derived designer drugs 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA, ecstasy), 3,4-methylenedioxy-N-ethylamphetamine (MDEA) and N-methyl-benzodioxolylbutanamine (MBDB) in urine. These drugs are often encountered in forensic and clinical toxicological analysis.

METHODS: GC-MS method after mixed-mode solid-phase extraction (SPE) and derivatization with heptafluorobutyric anhydride (HFBA) is presented for quick and reliable screening as well as identification and quantification of amphetamines and amphetamine derived designer drugs in urine.

RESULTS: The measurement of calibration dependence allowed to determine the extent of linearity in the concentration range from 10 to 2,000 ng/ml for all amphetamines except AMP and for all amphetamine-derived designer drugs with correlation coefficients exceeding 0.98. Detection limits were established at 5 ng/ml and quantification limits at 10 ng/ml for all analytes, except AMP. LOD for AMP was established at 20 ng/ml and LOQ at 50 ng/ml. Extraction efficiency for all analytes at concentration levels 50 and 500 ng/ml (n=6) was established in the range 60-99%. Repeatability was measured at concentration levels 50 and 500 ng/ml (n=6), relative standard deviations (RSDs) were under 10% for all analytes.

CONCLUSIONS: The GC-MS method after mix-mode solid-phase extraction and derivatization with heptafluorobutyric anhydride is presented for screening followed by identification and quantification of AMP, MAMP, EPH, NOREPH, MDA, MDMA, MDEA, and MBDB. The applicability of the GC-MS method was proven by analyzing authentic urine samples.