An HPLC Quantitative Analysis of Paraquat in Human Plasma: A Helpful Tool for Diagnosis and Evaluation of Treatment of Paraquat Poisoning in Vietnamese Hospitals

Abstract

In this paper, the paraquat (PQ) concentrations in plasma of poisoned patients were determined by high performance liquid chromatography (RP-HPLC) with a DAD detector followed simple extraction of PQ from plasma. The sample was simply pretreated with 15% trichloroacetic acid for deproteinization and directly injected to HPLC system. PQ in plasma was separated on a C8 column HPLC system using 2 channel mobile phase (A and B) with a volume ratio of 5:95, respectively. Channel A was 5% acetonitrile (ACN) and Channel B was a mixture of phosphate buffer (pH 2.5), sodium 1-heptanesulphonate (0.11% w / v), KCl (0.20% w / v), polyethylene glycol G400 (0.20% v / v) and methanol (20% v / v).

The flow rate of mobile phase was 0.5 mL/min. The method detection limit (MDL) is 0.013 ?g/ mL and the quantitative limit is 0.040 ?g/ mL. The recovery of PQ in plasma samples was 96.1% - 105.9 % at 5 different concentrations ranging from 0.040 ?g / mL to 10.00 ?g/ mL. The within- and between-day relative standard deviations were all less than 0.82% and 1.43% respectively. The method was successfully applied for determining paraquat concentrations in plasma samples of 31 acute paraquat poisoned patients at Poison Control Center, Bach Mai hospital, Vietnam. Quantitative results revealed that plasma PQ level was a key factor for prognosis and hemoperfusion using resin membrane had significant effect in removing PQ from the blood.