番茄、黄瓜及土壤中杀虫单总残留量的超高效液相色谱-电喷雾串联质谱检测

建立了番茄、黄瓜及土壤中杀虫单残留的超高效液相色谱-电喷雾串联质谱(UPLC-MS/MS)检测方法。先将杀虫单在碱性条件下水解成沙蚕毒素,经乙醚液-液分配后用甲醇定容,采用UPLC-MS/MS法测定沙蚕毒素浓度,最后再折算成杀虫单的残留量。结果表明:在1~500μg/L范围内,杀虫单质量浓度与峰面积呈良好的线性关系,相关系数均大于0.99;仪器检出限(LOD)分别为0.213μg/kg(番茄)、0.212μg/kg(黄瓜)和0.172μg/kg(土壤),定量限(LOQ)分别为0.710μg/kg(番茄)、0.707μg/kg(黄瓜)和0.573μg/kg(土壤);对于番茄、黄瓜及土壤样品,10、100和500μg/kg 3个水平的添加回收率试验结果显示,方法的平均回收率在79%~101%之间,相对标准偏差(RSD)为6.6%~16%。该方法可用于番茄、黄瓜及土壤中杀虫单残留量检测。

Determination of monosultap total residues in tomato, cucumber and soil by ultra-performance liquid chromatography- tandem mass spectrometry

An analytical method was developed for residue determination of monosultap in tomato, cucumber and soil samples by ultra-performance liquid chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS). Firstly, monosultap was hydrolyzed to nereistoxin under alkaline condition. Then, after liquid-liquid partition with ether, the organic layer was evaporated and restructed in methanol. The formed nereistoxin was detected by UPLC-MS/MS, and the residue of monosultap could be calculated accordingly. Results showed good linearity ranging from 1 to 500 μg/L with correlation coefficients higher than 0.99; the limit of detection (LOD) was 0.213 μg/kg (tomato matrix), 0.212 μg/kg (cucumber matrix) and 0.172 μg/kg (soil matrix), and the limit of quantification (LOQ) was 0.710 μg/kg (tomato matrix), 0.707 μg/kg (cucumber matrix) and 0.573 μg/kg (soil matrix). For tomato, cucumber and soil samples, average recoveries ranged from 79% to 101% at spiked level 10,100 and 500 μg/kg, and the relative standard deviations (RSD) was between 6.6% and 16%. The developed method is suitable for determination of monosultap total residues in tomato, cucumber and soil samples.