Development of an isotope dilution liquid chromatography/tandem mass spectrometry method for the accurate determination of neonicotinoid pesticides, imidacloprid, clothianidin, and thiamethoxam in kimchi cabbage reference materials

Abstract A method based on isotope dilution liquid chromatography/tandem mass spectrometry (ID-LC/MS/MS) was established as a candidate reference for accurate determination of neonicotinoid pesticides, imidacloprid, clothianidin, and thiamethoxam in kimchi cabbage. Their deuterated isotopes, imidacloprid- d 4 , chlothianidin- 3 thiamethoxam- were used internal standards. The combination HLB Carb solid-phase extraction (SPE) cartridges to clean-up cabbage extracts. ID-LC/MS/MS conditions optimized with fortified samples validation. Imidacloprid the ERM-BC403 cucumber sample (0.627 ± 0.026) mg/kg analyzed developed method, measured value (0.604 0.028) agreed within their uncertainties. employed certification materials prepared this laboratory. values are (0.860 0.020) mg/kg, (0.524 0.012) (0.787 0.014) respectively. standard deviation ten bottles < 1%, after one year first measurements indicating reliable repeatability reproducibility method.