Evaluation of chiral pesticides remains a frequently neglected matter in routine food control laboratories. This fact is due to the existence of many residue definitions but also due to the lack of robust instrumental methods for the evaluation of these isomeric compounds. However, supercritical fluid chromatography coupled to mass spectrometry (SFC-ESI-MS/MS) has been demonstrated to perform fast and highly efficient separations without the need to change the mobile phase employed in multiresidue pesticide analyses. Regarding chiral stationary phase columns, the polysaccharide-based ones clearly demonstrate the best separation technology. Two polysaccharide-based columns were tested in this study, and the robustness of their combination with SFC was verified. The enantiomers of lambda-cyhalothrin and metalaxyl were studied precisely due to their markedly distinct toxicity and enantioselectivity. Furthermore, the acute reference dose for gamma-cyhalothrin is half in comparison with its enantiomer (0.0025 and 0.005 mg/kg respectively), which is present in the lambda-cyhalothin residue definition. These enantiomers were analyzed in terms of linearity, reproducibility, and matrix effects in four representative matrices (tomato, orange, leek, and cayenne). Additionally, field tests under greenhouse conditions for these compounds were performed. The results obtained after different sample collections revealed a similar degradation in lambda-cyhalothrin enantiomers (R, S, S, and S, R, R) but not in the case of metalaxyl-M (mefenoxam) where the degradation in tomato was 2 to 6 times less in comparison with its S-enantiomer.

中文翻译：

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超临界流体色谱分离手性农药：研究氟氯氰菊酯和甲霜灵的独特能力。

在常规食品控制实验室中，手性农药的评估仍然是经常被忽略的问题。这一事实是由于存在许多残基定义，也是由于缺乏用于评估这些异构化合物的可靠仪器方法。但是，超临界流体色谱-质谱联用技术（SFC-ESI-MS / MS）已被证明可以快速高效地进行分离，而无需改变多残留农药分析中使用的流动相。关于手性固定相色谱柱，基于多糖的色谱柱清楚地展示了最佳的分离技术。在这项研究中测试了两个基于多糖的色谱柱，并验证了它们与SFC结合的稳健性。λ-氟氯氰菊酯和甲霜灵的对映异构体由于其明显不同的毒性和对映选择性而被精确研究。此外，γ-氟氯氰菊酯的急性参考剂量与其对映异构体（分别为0.0025和0.005 mg / kg）相比，是λ-氟氯氰菊酯残基定义中的一半。在四个代表性矩阵（番茄，橙，韭菜和辣椒）中，根据线性，可重复性和基质效应对这些对映异构体进行了分析。另外，在温室条件下对这些化合物进行了现场测试。收集不同样品后获得的结果表明，λ-氟氯氰菊酯对映体（R，S，S和S，R，