Post-mortem serum concentration of cantharidin in a fatal case of cantharides poisoning

A patient admitted to hospital died shortly after admission without a proper diagnosis having been made. Symptoms as well as the presence of a brown powder found in the possession of the deceased indicated the possibility of cantharidin intoxication. Cantharidin was positively identified by means of a GC/MS analysis, utilizing the selected ion monitoring technique (SIM), for m/z = 197.0813, (M + H+) for cantharidin, under positive chemical ionization conditions at a resolution of 7000 and a mass window of 30 ppm. Quantitation was done by means of a GC/MS SIM analysis of a toluene extract of acidified post-mortem serum under El+ conditions at a resolution of 3000, using clofibrate as internal standard and monitoring m/z = 128.0473 and 128.0029 for cantharidin and clofibrate respectively. The post-mortem serum was found to contain cantharidin at a concentration of 72.3 ng/ml whilst the cantharides powder contained 0.87% cantharidin.