An analytical method for the determination of residues of spiromesifen (OberonReg.) and its main metabolite in and on plant materials by HPLC with electrospray and MS/MS-detection.

摘要

A method for the determination of BSN 2060 (spiromesifen) and BSN 2060-enol residues in broccoli, bean, maize, cotton seed, cucumber, pepper, melon, strawberry, beetroots and tomato was described. The method was validated for sample analysis with and without clean-up. Both compounds were extracted from plants using a mixture of acetonitrile/water. For analysis without clean-up, an internal deuterated standard was added to the extract before dilution with water. The residues were quantified by reversed phase HPLC with electrospray and MS/MS-detection. This method required an API 3000 or equivalent HPLC-MS/MS instrument with comparable sensitivity. Otherwise a clean-up and concentration step was needed. The method was validated by conducting recovery experiments with different plant samples. Control samples were spiked with a standard solution containing BSN 2060 and BSN 2060-enol at fortification levels of 0.01 and 0.1 mg/kg. The lowest fortification level corresponded to the limit of quantitation (LOQ). The method without clean-up resulted in an overall mean recovery of 97% for BSN 2060. For the clean-up procedure it was 87%. For BSN 2060-enol, the corresponding values were 96 and 90%, respectively. The limit of detection (LOD) was at least 10 times lower (0.001 mg/kg) than the LOQ, as can be concluded from the linearity response data observed in control sample chromatograms. The repeatability was determined with a mixture of both compounds in different samples running 5 recoveries for both 0.01 and 0.1 mg/kg. The resulting relative standard deviation was below 15% with a mean recovery of 78 to 98% for both compounds..