Community Reference Laboratory (DG SANCO) for Residues of Pesticides in Fruits and Vegetables, Pesticide Residue Research Group, Department of Hydrogeology and Analytical Chemistry, University of Almería, 04120 La Cañada de San Urbano, Almería, Spain.
Anal Bioanal Chem. 2010 Nov;398(5):2299-306. doi: 10.1007/s00216-010-4100-2. Epub 2010 Aug 21.
This work reports a method for extraction and analysis of thiosultap sodium, thiocyclam, and nereistoxin in pepper. Different extraction methods were tested to attain the best recoveries. The final extraction method combines acetonitrile extraction in an acidic medium with ultrasonic extraction followed by a cleanup step with anhydrous MgSO(4). The analyses were performed on a Linear Ion Trap Quadrupole LC-MS/MS in negative mode for thiosultap sodium and in positive mode for thiocyclam and nereistoxin. Recovery studies carried out on peppers spiked at different fortification levels (20 and 200 μg∙kg(-1)) yielded average recoveries in the range 58-87% with RSD (%) values below 20%. Calibration curves covering two orders of magnitude were performed and they were linear over the concentration range studied (0.001-0.5 mg∙l(-1)). Instrumental detection limits were in the low μg∙kg(-1) range. Stability studies of thiosultap sodium in water were performed by evaluating a 100-μg∙l(-1) solution of this compound in water. It was analyzed over 7 days, after which more than 80% degradation of thiosultap sodium could be observed.
本工作报道了一种从辣椒中提取和分析硫代苏糖醇钠、噻虫环胺和新烟碱的方法。测试了不同的提取方法以达到最佳的回收率。最终的提取方法是在酸性介质中用乙腈提取，然后用超声提取，再用无水硫酸镁进行净化。采用负离子模式分析硫代苏糖醇钠，采用正离子模式分析噻虫环胺和新烟碱，在 Linear Ion Trap Quadrupole LC-MS/MS 上进行分析。在不同加标水平（20 和 200μg·kg(-1)）下对辣椒进行的回收率研究表明，回收率在 58-87%之间，相对标准偏差（%）值低于 20%。进行了两个数量级的校准曲线，在研究的浓度范围内呈线性。仪器检测限处于低μg·kg(-1)范围。通过评估 100μg·l(-1)的水中硫代苏糖醇钠溶液在水中的稳定性研究。在 7 天内进行了分析，之后可以观察到硫代苏糖醇钠的降解超过 80%。
