Simultaneous Determination of 37 Organophosphorus and 10 Pyrethroid Pesticides in Sludge by GC-MS after Extraction with ASE

A method was developed for the simultaneous determination of 37 organophosphorus and 10 pyrethroid pesticides in sludge from sewage treatment plant by GC-MS after extraction with ASE. After freeze-drying, the sludge sample was extracted twice by the mixed solution of acetone and n-hexane with volume ratio of 1:1 in the extraction tank with diatomaceous earth at 110℃ and 10.0 MPa. After the extraction solution was concentrated under reduced pressure, purified by graphitized carbon black solid phase extraction cartridge with mixed colution of acetone and n-hexane with volume ratio of 1:1 as eluant at a flow rate of 4 mL·min^-1. Analytes in the eluate adsorbed on the DB-1701 pchromatographic column were separated under programmed temperature, detected by MS with EI. Matrix matching mixed standard solution series were used to make standard curves. The results showed that mass concentrations of the 47 target compounds were linearly related with respective peak areas in the range of 2.00-100.0 mg·L^-1, with limits (3.143s) of detection in the range of 0.04-0.19 mg·kg^-1. The spiked recovery test was made on the actual samples, giving values of recovery in the range of 58.0%-118%, and RSDs (n=6) of the determined values ranged from 0.80% to 7.4%. The proposed method was used to analyze sludge samples from sewage treatment plants, chlorpyrifos (0.23 mg·kg^-1), diazinon (0.39 mg·kg^-1), and amphion (0.71 mg·kg^-1) were detected, with their contents all less than those specified by GB 36600-2008.