液相色谱手性拆分高效氯氟氰菊酯对映体

[方法]对映体分离是研究手性农药在环境中的选择性行为的重要前提之一,而高效液相色谱法是目前应用最为普遍的对映体分离和制备方法.对高效氯氟氰菊酯在纤维素-三-(3,5-二甲基苯基氨基甲酸酯)(Chiralcel OD-H)手性柱上的分离进行了研究,考察了流动相组成、流速以及柱温对分离效果的影响,并对高效氯氟氰菊酯对映体与固定相之间保留和分离的热力学机理进行了讨论.[结果]分别以5种体积比均为15%的醇改性上E己烷,分离因子(а)的变化顺序为异丁醇>异丙醇>正丁醇>正丙醇>乙醇;在0.4～1.1mL/min的流速范围内.分离度(Rs)随着流速的增大而逐渐减小;柱温在15～35℃范围内变化时,随着温度的升高分离闪子(а)呈降低趋势,两对映体的lnа与1/T呈良好的线性关系.手性拆分过程受焓的控制.[结论]在柱温为25℃,正己烷-异丙醇(体积比90:10)为流动相,流速1.0 mL/min时,高效氯氟氰菊酯对映体能达到基线分离,分离因子(а)和分离度(Rs)分别为1.55和4.07.     

高效液相色谱直接光学拆分手性农药(英文)

Enantiomer separation is one of the most important prerequisites for the investigation of environmental enantioselective behavior for chiral pesticides.The enantiomeric separation of three chiral pesticides,indoxacarb,lambda-cyhalothrin,and simeconazole,were studied on cellulose tris-(3,5-dimethylphenyl-carbamate)-coated chiral stationary phase(CDMPC-CSP) using high-performance liquid chromatography under normal phase condition.The effects of chromatographic conditions,such as the mobile phase composition including the concentration and type of alcohol modifiers in hexane,flow rate and column temperature,on enantiomer separation were examined.The thermodynamical mechanism of enantioseparation and chiral recognition mechanism were discussed.Better separation were achieved using 20% n-propanol for indoxacarb,2% iso-butanol for lambda-cyhalothrin,and 20% iso-propanol for simeconazole as modifiers in hexane at 25℃ with the selectivity factor(a) of 1.69,1.82 and 1.70,respectively.The resolution factor(Rs) decreased as the flow rate increased from 0.4 to 1.1 ml·min-1.The retention factor(k’) and selectivity factor for the enantiomers of analytes decreased as temperature increased.The lna-1/T plots for racemic chiral pesticides were linear in the range of 15-35℃ in hexane/iso-propanol and the chiral separation was controlled by enthalpy.Hydrogen bonding,π-π and dipole-dipole interactions between enantiomers and CDMPC-CSP play an important role in chiral identification,and the fitting of the asymmetric portion of solutes in a chiral cavity or channel of the CSP is also important.