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机构地区:[1]北京师范大学化学系
出 处:《色谱》1998年第3期265-267,共3页Chinese Journal of Chromatography
摘 要:利用脲衍生物型手性固定相正相直接拆分D,L-去甲麻黄碱对映异构体,优化的分离条件为正己烷-二氯乙烷-异丙醇(73.5251.5),异构体的出峰次序符合手性拆分的三点相互作用原理;同时探讨了不同的极性调节剂对分离的影响,并指出了四氢呋喃在拆分中的特殊作用。By using normal phase HPLC with urea derivative as chiral stationary phase(CSP), the direct separation of racemic norephedrine has been investigated. The resolution was optimized by varying the concentration of iso propanol in a ternary mobile phase which consists of two other components: hexane and 1,2 dichloroethane. The lower the percent of iso propanol, the better the resolution is. But the retention time is longer as the percent of iso propanol decreases. In an attempt to reduce the retention time without reducing the stereoselectivity, we chose the mixture of hexane, 1,2 dichloroethane and iso propanol as the mobile phase with a proportion of 73 5∶25∶1 5 in vol. We also altered the organic modifier by substituting ethanol, acetonitrile and tetrahydrofuran (THF) for iso propanol. The addition of ethanol appears to increase the hydrogen bond interactions between the solute and solvent, which results in lower k′ values and an increase in α and R s. Acetonitrile is only a kind of proton accepter and the interactions of hydrogen bonding between the solute and solvent are weaker than iso propanol, which results in higher k′ values and a reduction in α and R s. These separations are in agreement with the three point rule. When THF is used as organic modifier, a reversed elution order and a more favorable separation can be obtained. The specific behavior of THF in HPLC has not been explained satisfactorily yet.
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