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. 2018 Dec 19;66(50):13303-13309. doi: 10.1021/acs.jafc.8b04594. Epub 2018 Dec 6.
Bitertanol is a widely used triazole fungicide and consists of four stereoisomers. A new high-performance liquid chromatography (HPLC) method was developed for simultaneous analysis of the four stereoisomers in apple, pear, tomato, cucumber, and soil. The mechanism of separation was explained with molecular docking and effects of thermodynamic parameters on the resolution. The absolute configuration and optical rotation of four stereoisomers were confirmed by X-ray diffraction and HPLC tandem circular dichroism, respectively. A good linearity ( R ≥ 0.999) was obtained for four stereoisomers in all matrix-matched calibration curves in the range of 0.02-10 mg/L. The mean recoveries of four stereoisomers in five matrices ranged from 74.6% to 101.0% with an intraday and interday relative standard deviation from 0.6% to 9.9%. Stereoselective degradation of bitertanol in cucumber was observed: (1 R,2 S)-bitertanol and (1 R,2 R)-bitertanol were preferentially degraded with enantiomeric fraction values from 0.5 to 0.43 at 7 d and 0.42 at 5 d, respectively. This research provides a useful tool for the analysis of bitertanol stereoisomers.
双氧百菌清是一种广泛使用的三唑类杀菌剂，由四个对映异构体组成。本研究建立了一种新的高效液相色谱（HPLC）方法，用于同时分析苹果、梨、番茄、黄瓜和土壤中四个对映异构体。通过分子对接解释了分离机制，并研究了热力学参数对分辨率的影响。通过 X 射线衍射和 HPLC 串联圆二色性分别确定了四个对映异构体的绝对构型和旋光。四个对映异构体在所有基质匹配校准曲线的范围内（0.02-10mg/L）均具有良好的线性关系（R≥0.999）。四种对映异构体在五种基质中的平均回收率在 74.6%至 101.0%之间，日内和日间相对标准偏差在 0.6%至 9.9%之间。在黄瓜中观察到双氧百菌清的立体选择性降解：（1R,2S）-双氧百菌清和（1R,2R）-双氧百菌清优先降解，7d 时对映体分数值分别为 0.5 至 0.43，5d 时为 0.42。本研究为双氧百菌清对映异构体的分析提供了一种有用的工具。
