氟环唑对映体绝对构型的确定及残留分析方法研究

Study of Absolute Configuration and Residue Analysis Method for Epoxiconazole Enantiomers

采用Lux Cellulose-1手性柱,建立了氟环唑对映体的反相高效液相色谱拆分方法。采用高效液相CD检测器确定了氟环唑对映体的旋光性和流出顺序,通过比较实测圆二色光谱图与计算圆二色光谱图,确定了氟环唑对映体的绝对构型。在此基础上,建立了氟环唑对映体在蔬菜水果及土壤中的残留分析方法,系统评价了方法的精密度、准确度、灵敏度和基质效应。在优化条件下,即以乙腈-水(60∶40,V/V)为流动相、流速0.6 mL/min、柱温30℃、检测波长220 nm,实现了氟环唑对映体的基线分离。手性柱上流出的第一个峰为(S,R)-(-)-氟环唑,第二个峰为(R,S)-(+)-氟环唑。在0.1～10.0 mg/L的浓度范围内线性关系良好,无明显基质效应。氟环唑对映体在6种基质中的平均回收率在80. 8%～96. 7%之间,日间相对标准偏差为1.5%～6.1%,日内相对标准偏差为1.1%～6.7%;方法的最小检出量(LOD)为0.10～0.15 ng,定量限(LOQ)为0.05 mg/kg。本方法能满足食品和环境样品中氟环唑对映体的检测要求。

A method for separation of epoxiconazole enantiomers was established by reversed-phase high performance liquid chromatography(HPLC)on a Lux Cellulose-1 chiral column.The elution order of the epoxiconazole enantiomers was determined by HPLC coupled with a circular dichroism(CD)detector.The absolute configuration of epoxiconazole enantiomer was determined through comparison of experimental and predicted ECD spectra.Based on this,a simple and reliable method for simultaneous determination of epoxiconazole enantiomers in fruits and vegetables samples was established,and the method was systematically evaluated by the precision,accuracy,sensitivity and matrix effect of sample.When using acetonitrile-water(60∶40,V/V)as mobile phase with a flow rate of 0.6 mL/min,the epoxiconazole enantiomers were baseline separated at 30℃and detection wavelength of 220 nm.The first peak eluted from the Lux Cellulose-1 chiral column was confirmed to be(S,R)-(-)-epoxiconazole and the second peak was(R,S)-(+)-epoxiconazole.Excellent linearity of enantiomers was observed within concentration range of 0.1-10 mg/L,and there was no matrix effect.The results of the standard addition experiment showed that the average recovery of epoxiconazole enantiomers in the six matrices was 80.8%-96.7%,with inter-day precision(Relative standard deviation,RSD)of 1.5%-6.1%and intra-day RSD of 1.1%-6.7%.The limits of quantification(LOQs)for two enantiomers in six matrices were 0.05 mg/kg,whereas the limits of detection(LODs)were 0.10-0.15 ng.The analytical method could meet the requirement of simultaneous determination of epoxiconazole enantiomers in food and environmental samples.