Development of hollow fiber-supported liquid-phase microextraction and HPLC-DAD method for the determination of pyrethroid metabolites in human and rat urine

摘要

A simple hollow fiber liquid-phase microextraction method for the determination of synthetic pyrethroid metabolites, 3-phenoxybenzoic acid and 4-hydroxy-3-phenoxybenzoic acid, in human and rat urine was developed and validated. A polypropylene hollow fiber tightly fitted onto a Nylon rod and impregnated with organic solvent served as a disposable extraction device. Desorption of analytes was carried out in NaOH solution, analyzed further by gradient HPLC and diode array detection method. Important factors were identified using Taguchi OA16 (45) orthogonal array design and further optimized using univariate approach. The optimum method performance was observed when 1mL of urine hydrolyzed with 0.2mL of concentrated HCl was further supplemented with 100mg of NaCl and extracted for 120min into dihexyl ether immobilized in the pores of the hollow fiber. Metabolites were desorbed into 0.1mL of 0.1M NaOH for another 120min. Limits of detection and quantitation of 15 and 50ng/mL were obtained for both analytes. Relative standard deviations of 1.6-12.6% over the linear range (50-10,000ng/mL, r0.9906) were observed. Intra- and inter-day accuracies of the method ranged from 98.3 to 109.5% and from 93.3 to 110.9%, respectively. The optimized method was applied to the analysis of real urine samples collected from rats exposed orally to cypermethrin.