Determination of paraquat and diquat by HPLC/MS/MS

Paraquat and diquat contained in human whole blood and urine samples have been analyzed by high-performance liquid chromatography (HPLC)/tandem mass spectrometry (MS/MS) with positive ion electrospray ionization. Paraquat, diquat and ethyl paraquat as internal standard (IS) formed base peaks due to [M-H]+ ions by HPLCIMS. By use of HPLC/MS/MS, the product ions produced from each quasi-molecular ion showed the base peaks at m/z 169 for paraquat, m/z 157 for diquat and m/z 185 for IS. Selected reaction monitoring (SRM) and selected ion monitoring (SIM) were compared for the detection of the compounds from whole blood and urine. SRM showed much higher sensitivity than SIM for both types of sample. Therefore, recovery rates, regression equations and detection limits were studied for paraquat and diquat by SRM with HPLC/MS/MS. The recoveries of paraquat and diquat extracted from whole blood were 57-79 %; those from urine were 91-94 %. The regression equations for paraquat and diquat showed excellent linearity in the range of 0.5-10 ng on column with the detection limits of 0.25 ng on column for whole blood and 0.1 ng on column for urine.rights:日本法中毒学会rights:本文データは日本法中毒学会の許諾のもと掲載しています