Simultaneous determination of spirotetramat and its four metabolites in Spinacia oleracea L., soil and water using liquid chromatography-tandem mass spectrometry

A rapid and sensitive method based on QuEChERS and solid phase extraction using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in negative ion scanning and multiple reaction monitoring (MRM) mode was developed for the residue detection of spirotetramat and its four metabolites (B-enol, B-keto, B-mono and B-glu) in Spinacia oleracea L., soil and water. When using aqueous phase of acetonitrile-0.5% formic acid as the mobile phase, gradient elution resulted in the best chromatographic resolution and sensitivity. When 0.1% formic acid-acetonitrile solution was used as the extraction solvent and the samples was purified by 50 mg m (PSA): m (GCB) = 1: 1, at the fortification levels of 0.05, 0.5 and 1mg/kg, the recoveries of spirotetramat and its four metabolites in spinach and soil were 81%-103% and 82%-98%, the RSD were 1.7%-7.9% and 1.9%-7.6%, respectively. The recoveries of spirotetramat and its four metabolites in water was 82%-95%, the RSD was 1.5%-6.2%, at the fortification levels of 0.005, 0.05 and 0.5 mg/L when the NH2 column was used as the solid phase extraction column and 10 mL of dichloromethane was used as the elution solvent. At concentrations ranging from 0.002-1 mg/L, there were good linear relationships between the mass concentration of spirotetramat and its four metabolites and the corresponding peak area, the correlation coefficients (r) were in the range 0.996 7-0.999 7. The limits of detection (S/N = 3) for all analytes were 0.000 2-0.000 3 mg/kg (spirotetramat), 0.000 1-0.000 3 mg/kg (B-enol), 0.000 4-0.000 6 mg/kg (B-keto), 0.000 4-0.000 7 mg/kg (B-mono), 0.000 2-0.000 6 mg/kg (B-glu), respectively. The limits of quantification (S/N = 10) for all analytes were 0.000 6-0.001 mg/kg (spirotetramat), 0.000 3-0.001 mg/kg (B-enol), 0.001 2-0.001 6 mg/kg (B-keto), 0.001 2-0.001 9 mg/kg (B-mono), 0.000 6-0.001 3 mg/kg (B-glu), respectively. The method analysis results met the requirements for pesticide residue analysis. And this method is applicable to simultaneous detection of spirotetramat and its four metabolites in spinach, soil and water.