含盐流动相损坏色谱柱原因分析

用高压液相色谱（HPLC）分析某种原料药，采用KH2PO4缓冲液（pH值6．5）和甲醇组成的流动相进行梯度洗脱时，连续损坏两根新的色谱柱。经柱外梯度洗脱模拟实验发现：流动相pH值随着有机相比例的上升而上升，最终超过色谱柱允许的pH值上限而使色谱柱损坏；同时，当有机相的比例超过80％（体积比）时，有磷酸盐晶体析出，发生堵塞，从而加重了色谱柱的损坏。所以，在梯度洗脱时，应该做柱外模拟试验，确定有机相最高比例，以保护色谱柱。

Research the Reason of Phosphate Buffer Mobile Phase Damages Chromatography Column

A raw medical was analysed by high-pressure liquid chromatography（HPLC）, in which potassium phosphate buffer（pH6.3） was used as mobile phase by gradient elution, then two new column were damaged in this condition. The reason was founded in an outside-column simulated test： The pH of mobile phase was raised with the increase of organic phase ratio. At last, the pH of mobile phase exceeded the per mitted upper limit of the column and hurted the column. At the same time, it was also founded that in the test： phosphate salt would crystallized when the organic phase ratio exceeded 80% （v%）. When the or ganic phase ratio was reduced to 10%（v%）,the same type column was used normally for 3 years.