Liquid chromatography-atmospheric pressure ionization electrospray mass spectrometry determination of "hallucinogenic designer drugs" in urine of consumers

A procedure based on liquid chromatography-mass spectrometry (LC-MS) is described for determination of 3,4-methylenedioxymethamphetamine (MDMA), 2,5-dimethoxy-4-methyl-phenethylamine (2C-D), 4-bromo-2,5-dimethoxy-β-phenethylamine (2C-B), 1-(8-bromo-2,3,6,7-tetrahydrobenzo[1,2-b:4,5-b'] difuran-4-yl)-2-aminoethane (2C-B-Fly), 4-ethylthio-2,5-dimethoxy-β-phenethylamine (2C-T-2), 4-iodo-2,5-dimethoxy-β-phenethylamine (2C-I), and 4-ethyl-2,5-dimethoxy-β-phenethylamine (2C-E), 1-(m-chlorophenyl)piperazine (m-CPP), 4-hydroxy-N,N-diisopropyltryptamine (4-OH-DIPT) and 4-acetoxy-N,N-diisopropyltryptamine (4-acetoxy-DIPT) in urine of consumers using 3,4 methylendioxypropylamphetamine (MDPA) as internal standard. Sample preparation involved a solid-phase extraction procedure at pH 6 of both non-hydrolyzed and enzymatically hydrolyzed urine samples. Chromatography was performed on a C18 reversed-phase column using a linear gradient of 10 mM ammonium bicarbonate, pH 7.3 and acetonitrile as a mobile phase. Separated analytes were determined in LC-MS single ion monitoring mode using an atmospheric pressure ionization-electrospray ionization (ESI) interface. The assay was tested on urine samples from consumers of compounds under investigation (n = 32). Limits of quantification varied between 20 and 60 ng/mL for the different analytes under investigation. Calibration curves were linear to 2000 ng/mL for all the substances under investigation, with a minimum r2 > 0.99. At three concentrations spanning the linear dynamic range of the assay, mean recoveries ranged between 55.4 and 95.6% for the different analytes. Higher analytes concentrations in hydrolyzed samples showed the presence of conjugated compounds in urine. © 2008 Elsevier B.V. All rights reserved.