胆固醇基键合相-反相高效液相色谱法测定正辛醇/水分配系数

Determination of n-octanol/water partition coefficient by reversed-phase high performance liquid chromatography with cholesteryl-bonded phase

通过反相高效液相色谱法系统地考察了中性和弱酸性化合物在新型胆固醇基键合相色谱柱(Cholester柱)上的保留行为。以甲醇和乙腈为有机调节剂,建立了保留因子(k)与有机调节剂比例(φ)间的关系,并外推获取100%水相为流动相时的log kw;同时进一步建立并验证了不同流动相下正辛醇/水分配系数的对数(log Kow)和log kφ(log kw)间的模型,并预测了部分化合物的log Kow。结果表明,使用Cholester柱测定log Kow时,甲醇比乙腈更适合作为有机调节剂;对中性化合物和中性状态的酸性化合物,可以用任意甲醇比例下获取的log kφ预测log Kow;对存在离解的酸性化合物,依然用外推方式获取的log kw预测log Kow。将采用Cholester柱与文献中采用C18柱、C8柱建立的log Kow-log kφ模型进行对比,结果表明化合物与胆固醇基键合相存在特别的作用。

Retention behaviors of neutral and weak acidic compounds were studied systematically on a novel cholesteryl-bonded phase column. The relationships between retention factor (k) with volume fraction of organic modifier (phi) were established for each compound with methanol and acetonitrile as organic modifiers. The values of log k(w) corresponding to 100% water as mobile phase were obtained by extrapolating procedure. Models of the logarithm of n-octanol/water partition coefficient (log K-ow) versus log k(phi) (log k(w)) with different mobile phases were established. The values of log k(w) of some compounds were predicted with validated models. The results indicated that methanol as organic modifier was more suitable for determination of log K-ow with cholester columns than acetonitrile. For neutral or acidic compounds in neutral forms, the values of log k(w) could be predicted with log k(phi) from mobile phases with any volume fraction of methanol; for acidic compounds ionized in the mobile phases, the values of log k(w) were predicted with the extrapolated log k(w) values. Comparison of log K-ow-log k(phi) models established on cholester columns in this work with those established on C-18 and C-8 columns from the references indicated that it exists special interactions between compounds and the cholesteryl-bonded phase, which deserves further study.