Rapid drug-screening and quantitation of 3,4-methylenedioxymethamphetamine in urine by MALDI-TOF mass spectrometry

A method for the rapid screening of the drugs, 3,4-methylenedioxymethamphetamine (MDMA), in urine by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS) is described. In this method, α-cyano-4-hydroxycinnamic acid (CHCA) is used as the matrix for the MALDI samples. The identity of MDMA was confirmed by flight time of the fragmentation ([M + H]+ ion) using a mass calculation curve, the quantification of MDMA was achieved using stable-isotope-labeled MDMA (MDMA-D5) as the internal standard. For the analysis of MDMA/MDMA-D5-spiked urine samples, the calibration curve was linear in the range of 0.1-100 ppm with a coefficient of determination, r2, of 0.9993. This assay was used to determine MDMA in actual urine samples. The MALDI-TOFMS results were comparable to the GC/MS results. No significant bias is shown between the two methods by t-test at 95% confidence level. We conclude that MALDI-TOFMS can serve as a reliable and complementary method to GC/MS for use in forensic analysis.