Determination of Paraquat and Diquat Residues in Water by High Performance Liquid Chromatography-Tandem Mass Spectrometry with Solid Phase Extraction

KeyWord:water  paraquat  diquat  solid phase extraction£¨SPE£©  high performance liquid chromatography-tandem mass spectrometry£¨HPLC-MS/MS£©  pesticide residues

Abstract:

      A method was developed for the determination of paraquat and diquat residues in water by high performance liquid chromatography-tandem mass spectrometry with solid phase extraction.The samples were cleaned up by Cleanert PWCX solid phase extraction,separated on a HILIC column using acetonitrile-5 mmol/L ammonium acetate£¨pH 3ª±7 with formic acid£© as mobile phase by gradient elution,then detected in SRM mode and quantified by external standard method with the matrix matched calibrations.The calibration curves for paraquat and diquat showed good linearities in the concentration ranges of 10ª±0-200ª±0 ¦Ìg/L and 1ª±0-200ª±0 ¦Ìg/L,respectively,with correlation coefficients£¨r2£© no less than 0ª±997.The average recoveries for paraquat and diquat in agricultural environmental water at spiked levels of 30-200 ¦Ìg/L were in the ranges of 96ª±8%-125ª±8% and 97ª±2%-118ª±2%,with intra assay relative standard deviations£¨RSDs£© of 3ª±0%-6ª±3% and 2ª±9%-6ª±0%,and inter assay relative standard deviations of 3ª±3%-8ª±2% and 2ª±7%-7ª±9%,respectively.The limits of detection£¨LODs£© and quantitation£¨LOQs£© of the method were 5ª±0 ¦Ìg/L and 0ª±3 ¦Ìg/L,and 10ª±0 ¦Ìg/L and 1ª±0 ¦Ìg/L,respectively.The results indicated that the developed method is easy,fast and sensitive,its indicators such as the linear range,recovery,precision and detection limit could meet the requirements for residue analysis.The method is suitable for the determination of paraquat and diquat in agricultural environmental water