Zhao Wei, Lu Zhiqiang, Yang Shiyuan, Ji Xin, Wang Minghua, Shi Haiyan
State Key Laboratory of Agricultural and Forestry Biosecurity, Department of Pesticide Science, College of Plant Protection, State & Local Joint Engineering Research Center of Green Pesticide Invention and Application, Nanjing Agricultural University, Nanjing 210095, China.
J Agric Food Chem. 2025 Jul 2;73(26):16220-16228. doi: 10.1021/acs.jafc.5c04435. Epub 2025 Jun 23.
Fenoxanil is a chiral amide fungicide mixture that comprises two enantiomeric pairs. This study describes the baseline separation of fenoxanil stereoisomers via ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry using a Lux Cellulose-3 chiral column. The absolute configuration of the fenoxanil stereoisomers was confirmed via electronic circular dichroism. The elution sequence of the four fenoxanil stereoisomers was (1,2)-(+)-, (1,2)-(-)-, (1,2)-(+)-, and (1,2)-(-)-fenoxanil. The average recoveries of the fenoxanil stereoisomers in brown rice, rice husk, and rice plant ranged from 70.1% to 109.4%, with intraday and interday relative standard deviations of <9.4 and <11.7%, and a limit of quantitation of 0.05 mg/kg. Bioactivity assays against revealed that (1,2)-(+)-fenoxanil is a highly bioactive stereoisomer, with 3.7- and 21.7-times higher bioactivity than the mix-fenoxanil (four stereoisomer mixture) and (1,2)-(-)-fenoxanil, respectively. The contribution rate of (1,2)-(+)-fenoxanil to the total bioactivity was 96.6%. The chiral carbon atom linked to the cyano group was identified as being crucial to the bioactivity of fenoxanil, with (1,2)-fenoxanil exhibiting 2.2 times higher activity than the stereoisomer mixture. The findings of the study provide a basis for the reduction of fenoxanil use by using a single high-efficiency isomer, which is important for food safety and environmental protection.
粉唑醇是一种手性酰胺类杀菌剂混合物，由两对对映体组成。本研究描述了通过超高效液相色谱-串联质谱联用，使用Lux Cellulose-3手性柱对粉唑醇立体异构体进行基线分离。通过电子圆二色光谱确定了粉唑醇立体异构体的绝对构型。四种粉唑醇立体异构体的洗脱顺序为(1,2)-(+)-、(1,2)-(-)-、(1,2)-(+)-和(1,2)-(-)-粉唑醇。粉唑醇立体异构体在糙米、稻壳和稻株中的平均回收率为70.1%至109.4%，日内和日间相对标准偏差分别<9.4%和<11.7%，定量限为0.05 mg/kg。针对[具体对象未给出]的生物活性测定表明，(1,2)-(+)-粉唑醇是一种高生物活性的立体异构体，其生物活性分别比混合粉唑醇（四种立体异构体混合物）和(1,2)-(-)-粉唑醇高3.7倍和21.7倍。(1,2)-(+)-粉唑醇对总生物活性的贡献率为96.6%。与氰基相连的手性碳原子被确定为对粉唑醇生物活性至关重要，(1,2)-粉唑醇的活性比立体异构体混合物高2.2倍。该研究结果为通过使用单一高效异构体来减少粉唑醇的使用提供了依据，这对食品安全和环境保护具有重要意义。
