Better hydrolysis and increased efficiency for urine drug testing using mixed-mode SPE with in-well hydrolysis

Most drugs and metabolites are conjugated prior to excretion in the urine. Methods to detect drug analytes in urine usually include enzyme hydrolysis to convert glucuronide metabolites back to their free form prior to LC-MS analysis to increase sensitivity. Optimum hydrolysis conditions depend upon the compounds of interest and the chosen enzyme. Here, we present a method for detection of approximately 100 drugs and metabolites in urine using mixed-mode polymeric cation exchange solid phase extraction (SPE). Four different glucuronidase enzymes and several incubation times and temperatures were evaluated to determine optimum hydrolysis conditions for seven commonly detected glucuronide metabolites. Samples were subjected to offline hydrolysis and SPE (EVOLUTE® EXPRESS CX, Biotage, Charlotte, NC) and results compared to an SPE plate that incorporates in-well hydrolysis (EVOLUTE HYDRO CX, Biotage).

Literature number: P175.V.1