环丙唑醇对映体的反相高效液相色谱分离及其热力学研究

在高效液相色谱反相条件下,利用手性色谱柱Lux Cellulose-1(纤维素-三(3,5-二甲基苯基氨基甲酸酯,粒径分别为3μm和5μm)对环丙唑醇4个对映异构体进行了直接手性拆分研究。考察了不同粒径、流动相组成和柱温对环丙唑醇对映体色谱保留及分离的影响;并采用在线旋光检测器研究了环丙唑醇对映体的洗脱顺序;同时,利用热力学方法对对映体与固定相之间的色谱保留和分离的热力学机理进行了探讨。结果表明:以乙腈-水为流动相比甲醇-水具有更好的拆分效果,柱温降低有利于对映体的拆分;在以V(乙腈)∶V(水)=60∶40为流动相、柱温为20℃的条件下,环丙唑醇对映体在3μm(流速0.3 m L/min)和5μm(流速1.0 m L/min)色谱柱上均可得到较好分离,在满足对映体完全分离的情况下,建议优先使用3μm色谱柱,异构体洗脱顺序为(+/+/-/-);而当流动相由乙腈-水变为甲醇-水时,对映体的洗脱顺序则变为(+/-/+/-)。热力学研究结果表明:在5~40℃试验温度范围内,van't Hoff方程的线性关系良好(R20.92);以乙腈-水作为流动相时,环丙唑醇对映体的拆分过程受焓驱动;而以甲醇-水为流动相时,对映体的拆分过程既受焓驱动又受熵驱动。

Enantiomeric separation and thermodynamic investigation of cyproconazole by reverse-phase high-performance liquid chromatography

The enantiomers of cyproconazole were separated by reverse-phase high-performance liquid chromatography using a chiral column Lux Cellulose-1 (cellulose-tris-(3,5-dimethylphenylcarba-mate),packed with 3 μm and 5 μm particles). The effects of different particle size, mobile phase composition and column temperature on the retention and resolution were investigated. Furthermore, the elution order of enantiomers was identified with an optical rotation detector. Moreover, the mechanism of enantiomeric separation was analyzed by measuring the thermodynamical parameters. The results showed that using acetonitrile-water as the mobile phase gave a better enantioseparation than the methanol-water system, and lower column temperature was more helpful for the separation. The ideal separation of cyproconazole on the 3 μm column at a flow rate of 0.3 mL/min and the 5 μm column at a flow rate of 1.0 mL/min could be achieved with V(acetonitrile):V(water)=60:40 at 20 ℃. When satisfactory enantioseparation was obtained, 3 μm column had the priority to be used and the elution order based on the optical rotation were(+/+/-/-). However, when the mobile phase changed from acetonitrile-water to methanol-water, the elution order would change to(+/-/+/-).Thermodynamic results show that the linear relationship of van't Hoff equation was good (R2 > 0.92) at the experimental temperature in the range of 5-40 ℃. The enantiomeric separation of cyproconazole was driven by enthalpy when using acetonitrile-water as the mobile phase. However, when using methanol-water as the mobile phase, the enantiomeric separation was driven by both enthalpy and entropy.