Objective: To establish a method to determine the presence and concentration of DEP, DMDTP, DEDTP, PNP, CMHC and TCPY organophosphorus pesticides metabolites in human urine by LC-MS/MS.
Method: 2.0 ml of urine was enzymatically hydrolyzed in water bath 37 degrees C for 4 hours, then the urine samples were solid-phase extracted by Oasis HLB and eluted with methanol, after centrifugation and concentration the urine samples were separated on waters symmetry C18 5 microm (2.1 mm x 150 mm) column with ammonium acetate buffer solution acetonitrile-water as mobile phase to constant gradient elution. Electrospray ionization source (ESI) was applied and operated in positive ion mode, and multiple reaction monitoring (MRM) mode was adopted.
Results: Within concentration ranging from 0 - 1000 ng/ml the correlation coefficient for 5 compounds of 6 were greater than 0.990, recoveries were between 79% - 130%, RSD < 8.2%. The RSD of intra-day and inter-day were less than 15% (n = 6).
Conclusion: The procedure of samples collection is simple. This is a accurate and specific method for testing organophosphorus pesticides metabolites in human urine.