Solid phase extraction with silicon dioxide microsphere adsorbents in combination with gas chromatography-electron capture detection for the determination of DDT and its metabolites in water samples

摘要

The goal of the present study was to investigate the feasibility of silicon dioxide (SiO_2) microspheres without special modification to enrich dichlorodiphenyltrichloroethane (DDT) and its main metabolites, p,p'-dichlorodiphenyl-2,2-dichloroethylene (p,p'-DDD) and p,p'-dichlorodiphenyldichloroethylene (DDE) in combination with gas chromatography-electron-capture detection. The experimental results indicated that an excellent linear relationship between the recoveries and the concentrations of DDT and its main metabolites was obtained in the range of 0.2-30 ng mL~(-1) and the correlation coefficients were in the range of 99.96-99.99％. The detection limits based on the ratio of signal to the baseline noise (S/N = 3) were 2.2, 2.9, 3.8 and 4.1 ng L~(-1) for p,p'-DDD, p,p'-DDT, o,p'-DDT, and p,p'-DDE, respectively. The precisions of the proposed method were all below 10％ (n = 6). Four real water samples were utilized for validation of the proposed method, and satisfactory spiked recoveries in the range of 72.4-112.9％ were achieved. These results demonstrated that the developed method was a simple, sensitive, and robust analytical method for the monitoring of pollutants in the environment.