吲(口朶)生物碱的高效液相色谱研究

HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC STUDIES OF INDOLE ALKALOIDS

在μ-Bondapak C_(18)柱上以不同比例的磷酸盐缓冲液和甲醇为流动相,在不同pH下研究了16个吲哚生物碱的保留行为以及结构和保留时间的关系。研究结果表明,大部分样品的容量因子(k′)随pH增加而增加,当pH为6左右时k′达到最大值,pH继续增加则k′下降。logk′和甲醇含量之间没有简单线性关系。磷酸盐和柠檬酸盐缓冲液的洗脱能力相近,醋酸盐缓冲液洗脱能力较弱。随磷酸盐缓冲液浓度增加k′缓慢下降。所研究的12个吲哚生物碱在μ-Bondapak C_(18)柱上以pH 7.5的磷酸盐缓冲液—甲醇(30:70)为流动相可得到最佳分离。

The chromatogphic behavior and the relationship between the retention and the structure of 16 indole alkaloids were investigated on a μ-Bondapak C18 column at different pH with different volume ratios of 0.02 mol/L KH2PO4—CH3OH as mobile phase and a photodiode array detector （DAD） was used. The experimental results demonstrate that the plots of the logarithm of capacity factor k’ of the indole alkaloids are nonlinear in the volume fraction of methanol and the capacity factors increase with increasing pH of buffer solution from 2 to 6 then decrease. The effect of different kinds of buffer solution on kt has also been examined. Phosphate and citrate buffer showed stronger elution strength for various indole alkaloids but acetate buffer was shown to be relatively weak. Increase of phosphate buffer concentration gives a little decrease on k’. These results indicate tha.t the optimized separation of 12 indole alkaloids studied in this work can be carried out isocratically in the system of pH 7.5 phosphate buffer—methanol （30:70） on a μ-Bondapat C18 column.