Determination and long-term stability of twenty-nine cathinones and amphetamine-type stimulants (ATS) in urine using gas chromatography–mass spectrometry

A method was developed for the screening and quantification of seven amphetamine-type stimulants (ATS) and 22 cathinones, including three metabolites, in urine with Gas Chromatography–Mass Spectrometry. This method allowed the detection and quantification of ATS and cathinones group molecules using one procedure. A study of the stability of the drug mixtures for a period of 201 days in human urine samples under three different conditions has been carried. The ATS and cathinones include amphetamine, methamphetamine, MDA, MDEA, MDMA, PMA, PMMA, cathinone, methcathinone, 3′-position-substituted, ring-substituted, methylenedioxy-substituted, N-alkyl-substituted and pyrrolidinyl-substituted. Twenty drugs out of twenty-nine were validated with a quantitative method. This method can be applied to the nine remaining drugs as a screening method. The linearity of the assay was from 50 to 2000 ng/ml, with limits of detection of 0.5 to 10 ng/ml. In terms of accuracy, between-run and within-run precision were ≤20% for 20 compounds with good selectivity. No carryover was seen, and the recovery was between 80 and 120% for most drugs tested. ATS and pyrrolidinyl-substituted groups were conducted to be stable compounds under all conditions. All compounds tested were stable at −20 °C. Some cathinones were primarily degraded after 21 days at 4 °C. They were detectable but unstable after 201 days at 4 °C. Most cathinones were unstable after a day and completely lost after 28 days at RT.