Abstract

An ion mobility spectrometry (IMS) method was developed for the rapid detection of mitragynine, the most abundant alkaloid in Mitragyna speciosa also known as kratom. The peak corresponding to the mitragynine protonated ion exhibited a reduced ion mobility of 0.95 ± 0.00014 cm²/(V s), and the mitragynine limit of detection using IMS was 0.5 ng. The IMS method was applied to the analysis of 15 commercial samples suspected of containing kratom. IMS results were compared to those obtained from liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis of the same samples. Mitragynine was conclusively detected in 14 of 15 samples using LC–MS/MS and 13 of 15 samples using IMS. The discrepancy between methods reflected the fact that one sample contained mitragynine at a concentration below the IMS detection limit. This study demonstrates the utility of IMS for the rapid screening of products containing kratom as well as the scientific reliability of the IMS screening method, which was demonstrated by comparing the IMS results to the confirmatory results obtained using LC–MS/MS.