Determination of paraquat and diquat in human body fluids by high-performance liquid chromatography/tandem mass spectrometry

• Published in: Journal of mass spectrometry. 2004-10, Vol.39 (10), p.1147-1152
• Main Authors: Lee, Xiao-Pen, Kumazawa, Takeshi, Fujishiro, Masaya, Hasegawa, Chika, Arinobu, Tetsuya, Seno, Hiroshi, Ishii, Akira, Sato, Keizo
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Animals; Biological and medical sciences; Body Fluids - chemistry; Chemistry; Chemistry, Clinical - instrumentation; Chromatographic methods and physical methods associated with chromatography; Chromatography, High Pressure Liquid - methods; diquat; Diquat - analysis; Diquat - blood; Diquat - urine; Exact sciences and technology; Herbicides - analysis; Herbicides - blood; Herbicides - urine; high-performance liquid chromatography; Humans; Mass Spectrometry - methods; Medical sciences; Other chromatographic methods; paraquat; Paraquat - analysis; Paraquat - blood; Paraquat - urine; Pesticides, fertilizers and other agrochemicals toxicology; Rats; tandem mass spectrometry; Toxicology
• ISSN: 1076-5174; 1096-9888
• DOI: 10.1002/jms.695

Paraquat (PQ) and diquat (DQ) in human whole blood and urine were analyzed by high‐performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) with positive ion electrospray ionization (ESI). The compounds were extracted with Sep‐Pak C18 cartridges from whole blood and urine samples containing ethyl paraquat as an internal standard. The separation of PQ and DQ was carried out using ion‐pair chromatography with heptafluorobutyric acid in 20 mM ammonium acetate and acetonitrile gradient elution for successful coupling with MS. Both compounds formed base peaks due to [M  H]+ ions by HPLC/ESI‐MS and the product ions produced from each [M  H]+ ion by HPLC/MS/MS. Selective reaction monitoring (SRM) showed much higher sensitivity for both body fluids. Therefore, a detailed procedure for the detection of compounds by SRM with HPLC/MS/MS was established and carefully validated. The recoveries of PQ and DQ were 80.8–95.4% for whole blood and 84.2–96.7% for urine. The calibration curves for PQ and DQ showed excellent linearity in the range of 25–400 ng ml−1 of whole blood and urine. The detection limits were 10 ng ml−1 for PQ and 5 ng ml−1 for DQ in both body fluids. The intra‐ and inter‐day precision for both compounds in whole blood and urine samples were not greater than 13.0%. The data obtained from the determination of PQ and DQ in rat blood after oral administration of the compounds are also presented. Copyright © 2004 John Wiley & Sons, Ltd.