Laboratory of Pesticide Residues and Environmental Toxicology, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing, 100083, China.
Environ Sci Pollut Res Int. 2023 Apr;30(19):55471-55484. doi: 10.1007/s11356-023-26227-7. Epub 2023 Mar 9.
Thiamethoxam and flonicamid are two representative insecticides of neonicotinoids which are used to treat cucumber aphids, causing food safety and human health problems. A 60% thiamethoxam-flonicamid commercial mixture water dispersible granule (WDG) is being prepared for registering in China, so it is essential to investigate the residue levels of these neonicotinoids and their metabolites in cucumber and evaluate the dietary risks of these insecticides. We developed a modified quick, easy, cheap, effective, rugged and safe (QuEChERS) method combined with high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) for the simultaneous determination of thiamethoxam and its metabolite clothianidin, flonicamid and its metabolites 4-trifluoromethylnicotinic acid (TFNA), 4-trifluoromethilnicotinamide (TFNA-AM), 4-(trifluoromethyl) nicotinol glycine (TFNG) in cucumber. Method validation indicated good selectivity, linearity (r ≥ 0.9996), accuracy (recoveries of 80-101%), precision (relative standard deviations (RSD) ≤ 9.1%), sensitivity (limits of detection (LOD), 0.28-1.44 × 10 mg/L; limits of quantification (LOQ), 0.01 mg/kg) and minor matrix effect (ME) ( ≤|± 5%|). In the terminal residue trials under good agricultural practice (GAP) conditions, the residue levels of six analytes in cucumber samples were ˂0.01-0.215 mg/kg after application trice with an interval of 7 days based on pre-harvest interval (PHI) of 3 days under the high recommended dosage of 54 g active ingredient/ha (g a.i./ha). Relevant toxicological, residual chemistry parameters and dietary consumption of the residents were applied to assess the potential risk of dietary exposure. The chronic and acute dietary exposure assessment risk quotient (RQ) values were less than 1. The above results indicated that the potential dietary intake risk of this formulation was negligible to consumers.
噻虫嗪和氟啶虫酰胺是两种典型的新烟碱类杀虫剂，用于防治黄瓜蚜虫，对食品安全和人类健康造成威胁。一种 60%噻虫嗪-氟啶虫酰胺的商业可湿性粉剂（WG）正在中国进行登记，因此有必要调查这些新烟碱类杀虫剂及其代谢物在黄瓜中的残留水平，并评估这些杀虫剂的膳食风险。我们开发了一种改良的快速、简便、廉价、有效、耐用和安全（QuEChERS）方法，结合高效液相色谱串联质谱法（HPLC-MS/MS），用于同时测定噻虫嗪及其代谢物噻虫胺、氟啶虫酰胺及其代谢物 4-三氟甲基烟酸（TFNA）、4-三氟甲基烟酰胺（TFNA-AM）、4-（三氟甲基）烟醇甘氨酸（TFNG）在黄瓜中的残留。方法验证表明具有良好的选择性、线性（r≥0.9996）、准确度（回收率为 80-101%）、精密度（相对标准偏差（RSD）≤9.1%）、灵敏度（检测限（LOD），0.28-1.44×10 mg/L；定量限（LOQ），0.01 mg/kg）和较小的基质效应（ME）（≤|±|5%）。在良好农业规范（GAP）条件下的最终残留试验中，根据 3 天的休药期（PHI），在推荐高剂量 54 g 有效成分/公顷（g a.i./公顷）下，3 次施药间隔 7 天，黄瓜样品中 6 种分析物的残留水平为 ˂0.01-0.215 mg/kg。应用相关毒理学、残留化学参数和居民膳食摄入量评估膳食暴露的潜在风险。慢性和急性膳食暴露评估风险商（RQ）值均小于 1。上述结果表明，该制剂对消费者的潜在膳食摄入风险可以忽略不计。
