Abstract:A method based on Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) dispersive solid-phase extraction coupled with high performance liquid chromatography tandem mass spectrometry was developed for the determination of pendimethalin in aquatic products. The samples were extracted with ethyl acetate containing 0.1% (V/V) formic acid, and the extracts were purified by dispersive solid-phase extraction with 0.6 g polystyrene-divinylbenzene (PS-DVB) and 0.2 g primary secondary amine (PSA) sorbents. The purified extracts were collected and concentrated at 40 ℃ to almost dry under nitrogen gas. The resulting extracts were re-dissolved in 1.0 mL of acetonitrile, filtered through microfiltration membrane (0.22 μm), and analyzed by high performance liquid chromatography-tandem mass spectrometry. The target compounds were separated on a Kinetex C18 column (100 mm×2.1 mm, 2.6 μm), and gradient elution was performed with acetonitrile and 0.1% (V/V) aqueous formic acid solution. Electrospray ion source (ESI) and selective reaction monitoring (SRM) were used for analysis, and the matrix-matched internal standard method was used for qualitative and quantitative determinations. The results showed that good linear relationship was in the range of 2~100 μg/L, with the correlation coefficient being 0.999 5. The limits of detection (LOD) and quantitation (LOQ) were 0.5 μg/kg and 1.0 μg/kg, respectively. The average recoveries of pendimethalin at three different spiking levels in a sample matrix carp, procambarus clarkiir or pelodiscus sinensis ranged from 78.9% to 110.6%, with RSDs ranging from 3.8% to 6.8% under. This method has the advantages of high speed, accuracy and sensitivity, and can meet the requirements for detecting pendimethalin residue in aquatic products from rice fields.
