Comparison of FIA and on-column LC-MS/MS method to measure simultaneously ABG, ASM, GAA, GALC, GLA and IDUA activities for Immunosuppressant Assay by LC-MS/MS

Lysosome is a membrane-enclosed organelle and contains hydrolytic enzymes. They can digest virtually all kinds of biomolecules. Some techniques such as fluorometric and spectrophotometric assays have been developed to measure these enzyme activities. Multiplex flow injection analysis using tandem mass spectrometry (FIA-MS/MS) method has been developed that simultaneously measures the activities of the enzymes, alphaglucocerebrosidase (ABG), sphingomyelinase (ASM), alpha-glucosidase (GAA), galactocerebrosidase (GALC), alpha-galactosidase A (GLA) and alpha-iduronidase (IDUA). The use of mass spectrometric techniques has exhibited advantages over the other techniques in the simultaneous quantiflcation of several targets. However, FIA-MS/MS method can exhibit background noise levels that lead to inaccurate data interpretation. Here we compared and evaluated FIA LC-MS/MS method and on-column LC-MS/MS method to simultaneously measure these enzyme activities.