QUANTITATION OF PARAQUAT IN SERUM BY HPLC

An HPLC method for the quantitation of paraquat in urine was applied to serum. Sample preparation consisted of ion-pair extraction on disposable cartridges of end-capped octadecyl silica. The paraqust thus extracted, was quantitated by HPLC using 1, 1′-diethyl-4, 4′-dipyridyl dichloride as an internal standard. Relatively small sample volumes (1 mL serum) were required. Within- and between-assay coefficients of variation for the HPLC technique were 2.9% and 4.0%, respectively, at low paraquat serum concentration (0.4 µg/mL), and 2.4% and 3.2% at high paraquat serum concentration (4.0 µg/mL). The between-assay coefficient of variation for the total procedure, including the extraction, was 5.6% at low concentration (0.4 µg/mL). Serum concentration levels down to 0.025 µg/mL could be quantitated. The technique was checked for interference from muscle relaxants (pancuronium bromide and vecuronium bromide) and from anticoagulants (heparin and K2EDTA). No interference was observed. © 1993 Oxford University Press.