A Novel Derivatization Method for the Determination of Saisentong in Soil by High-Performance Liquid Chromatography

Abstract

A novel and accurate derivatization method for the determination of saisentong in soil was developed by high-performance liquid chromatography. The derivatization efficiency of saisentong was affected by multiple experimental conditions, including derivatization reagent amount, reaction temperature and time, oscillation rate, and reactant ratio. These conditions were optimized using an orthogonal experimental design. The final derivative was identified by liquid chromatography-tandem mass spectroscopy. The optimum derivatization conditions were as follows: 50 mL of 1.0 mol L⁻¹ sodium thiosulfate-methanol (1:1, v/v), 2 h of heat assistance at 60 °C, and no oscillation. The derivatization efficiency of saisentong reached 70 % under these optimum conditions. The linear calibration ranges of the saisentong derivative were within 2.0–100.0 mg L⁻¹, and the limit of detection and limit of quantification of saisentong were 0.03 and 0.10 mg kg⁻¹, respectively. The average recoveries at three spiked levels ranged from 93.53 to 97.27 % for soil samples with relative standard deviations of 1.38 to 4.62 %. For field experiments, the half-lives of saisentong in soil samples from Guizhou and Hunan were 14.7 and 12.0 days, respectively. The proposed approach can be used to analyze saisentong residues from contaminated soil samples.