以离子液体为流动相添加剂高效液相色谱法分离钩藤药材中的钩藤碱和异钩藤碱

以常用流动相添加剂三乙胺作为对照,建立了以离子液体为流动相添加剂,分离钩藤药材中钩藤碱和异钩藤碱的高效液相色谱方法。以分离度及相关色谱参数为指标,选择了离子液体中咪唑阳离子烷基链长度及阴离子的种类。并分别考察了咪唑阳离子烷基链长度、离子液体浓度、流动相pH值和流动相比例对钩藤碱和异钩藤碱分离的影响,初步探讨了离子液体的分离机理。结果显示,咪唑阳离子的烷基链越长,阴离子的离子液体序列越高,分离效果越好,即HMIM]BF_4]为最优的流动相添加剂。当HMIM]BF_4]浓度为16 mmol/L,流动相pH值为3.0,甲醇比例为37%时,钩藤碱和异钩藤碱能够实现基线分离,满足样品分离测定的需求。

Separation of Rhynchophylline and Isorhynchophylline in Uncaria Rhynchophylla by HPLC with Ionic Liquids as Mobile Phase Additives

A reversed phase high performance liquid chromatographic(RP-HPLC) method for the simultaneous determination of rhynchophylline and isorhynchophylline in Uncaria Rhynchophylla was established by using ionic liquids as a mobile phase additive.With degree of separation and other related chromatographic parameters as indicators,the length of alkyl chain length and the type of anion in ionic liquid were selected.In addition,several influence factors,including imidazolium cation alkyl chain of ioinic liquids and concentration,mobile phase pH value and flow phase ratio were investigated.The probable mechanism of the separation with ionic liquids as mobile phase additives was also explored.The results showed that the longer the alkyl chain length of the cationic,the higher the separation efficiency of the anion,and the better the separation effect,that means theHMIM]BF4] is the optimal mobile phase additive.The experimental results showed that when the HMIM]BF4] concentration is 16 mmol/L,the pH value of mobile phase is 3.0,and methanol ratio is 37%,baseline separations of rhynchophylline and isorhynchophylline were obtained, which could satisfy the requirements of sample separation.