DETERMINATION OF PARAQUAT IN PLASMA AND URINE BY MICELLAR LIQUID CHROMATOGRAPHY

Abstract

The study aimed to apply micellar liquid chromatography (MLC) to detect paraquat levels in human plasma and urine samples at a medical decision level for suspected poisoning, which is not achieved by the current ion-pairing LC method. Paraquat in (acid-treated) human plasma and urine samples was analyzed using C18 Eclipse XDB column maintained at 30°C and an aqueous micellar mobile phase (pH 3.0) composed of 50 mM sodium dodecyl sulfate, 15% (v/v) acetonitrile, 0.5% (v/v) diethylamine, and 9% (v/v) n-butanol, with paraquat monitored by measuring absorbance at 258 nm. The limit of detection of plasma paraquat (PPQ) and urine paraquat (UPQ) was 0.02 and 0.05 µg/ml respectively; and the limit of quantification was 0.05 and 0.16 µg/ml respectively. Dynamic range for both PPQ and UPQ was achieved at 0.16-100 µg/ml and recovery of spiked (2-10 µg/ml) PPQ and UPQ samples ranged from 100.4-102.9%. Within run repeatability of PPQ and UPQ, detection was obtained at 1.8 and 3.5% relative standard deviation (RSD) respectively and within laboratory repeatability of 4.16 and 7.31% RSD respectively, with a turn-around time of eight minutes. In conclusion, the MLC method was capable of detecting paraquat at a medical decision level for suspected poisoning, namely, 0.2 and 0.9 µg/ml in plasma and urine respectively.