Determination of Pyrethroids in Environmental Waters Using Magnetic Chitosan Extraction Coupled with High Performance Liquid Chromatography Detection

Abstract

The magnetic chitosan was prepared by adding chitosan, Fe2+ and Fe3+ into a basic precipitant of NaOH solution. The synthetic magnetic chitosan was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and physical properties. The adsorption characteristics of magnetic chitosan for extracting pyrethroids from water samples were investigated. The analytes were separated by magnetic solid phase extraction and determined by high performance liquid chromatography. The optimum conditions of adsorption experiments were obtained: the amount of sorbent was 80 mg, the extraction time was 20 min, the washing solvent was 50% aqueous methanol, and the eluent was acetonitrile-acetic acid (99: 1, v/v). The obtained linearity of three pyrethroids was in the range of 30–3000 ng L−1. The detection limits of beta-cyfluthrin, cyhalothrin, and cyphenothrin were 7.5, 5.6, and 6.1 ng L−1, respectively. The intra-day and inter-day precisions of three pyrethroids were in the range of 3.6–5.2% and 5.9–8.6%, respectively. In the optimized conditions, three water samples were analyzed, and the recoveries of pyrethroids obtained were 83.2–95.2%.