Separation and quantification of paraquat and diquat in serum and urine bycapillary electrophoresis

The use of capillary electrophoresis (CE) for simultaneous qualitative and quantitative detection of paraquat (PQ) and diquat (DQ) in both serum and u rine was investigated. The two herbicides were extracted from biological fl uids with liquefied phenol. Serum required a deproteinization with chlorofo rm and ammonium sulfate as pretreatment. The extracts were hydrodynamically injected and the complete separation was carried out in 10 min, using a ca pillary tube (75 pin i.d., 500 mm) of fused silica containing 50 nM phospha te buffer (pH 2.50) as the carrier. UV absorbance detection at 200 nm was p erformed by an on-column detector. The analytes were characterized by their respective migration times. Analytical recoveries were 52.6% for PQ and 62 .6% for DQ in serum, and 71.4% and 59.3%, respectively, in urine. The linea rity was studied up to 4 mg/L and the limits of detection (LODs) were bette r than 5 pg/mL in serum or urine. The CE method described was applied to th e characterization of two lethal poisonings and results were related. Copyr ight. (C) 2001 John Wiley & Sons, Ltd.