Features of glucuronidated metabolites of the synthetic cannabimimetics detection in urine by LC-MC
In most cases, the screening of drugs in urine assumes carrying out time-consuming sample preparation. This procedure is considered necessary when establishing the intake of drugs undergoing extensive metabolism including conjugation. This feature is typical for synthetic cannabimimetic family: for detection of their metabolites the mineral or enzyme de-conjugation is usually assumed. The LC-MS detection of conjugates allows to skip this step. This article contains the comparison of several methods for extraction of glucuronidated metabolites of synthetic cannabimimetics. It is found that extraction of metabolites with acetonitrile or by reversed phase cartridges was most reliable, and advantage of the first method is simplicity of performance, and of the second - possibility to concentrate analytes. At LC-MS method development, the highest sensitivity was achieved with applying of positive mode electrospray ionization with elution of analytes by acid mobile phases. As glucuronidated metabolites undergo partial fragmentation in electrospray, the choice of ion-precursors was determined by degree of analytes decomposition and matrix effects.