Determination of Pyrethroids in Blood Plasma and Pyrethroid/Pyrethrin Metabolites in Urine by Gas Chromatography-Mass Spectrometry and High-Resolution

In this chapter, two analytical methods are presented suitable for the determination of pyrethroids in blood plasma and pyrethroid/pyrethrin metabolites in urine. As pyrethroids such as cyfluthrin, cypermethrin, deltamethrin, permethrin, and bioallethrin are metabolized very fast, they can only be detected within about 24 h after exposure; that is, the method shown should only be applied in case of intoxication. After solid-phase extraction, the sample is analyzed by high-resolution gas chromatography-negative chemical ionization mass spectrometry (HRGC-NCIMS) with a detection limit of 5 ng/L blood plasma. In all other cases of exposure (occupational surveillance, environmental, biological monitoring programs, etc.), the determination of metabolites in urine by gas chromatography-mass spectrometry (GC-MS) or HRGC-MS should be preferred. The urine method is adequate for the simultaneous determination of the pyrethroid metabolites cis - and trans -3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid, cis -3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid, 3-phenoxybenzoic, and 4-fluoro-3-phenoxybenzoic acid as well as of the pyrethrin/bioallethrin-specific metabolite trans -chrysanthemumdicarboxylic acid (-CDCA). After acid hydrolysis and sample extraction with tert-butyl-methylether, the residue is derivatized with 1,1,1,3,3,3-hexafluoroisopropanol and analyzed by HRGC-MS (detection limit 0.1 �g/L urine).