液相色譜柱的故障诊断与维护.docVIP

液相色谱柱的故障诊断与维护（二） 液相色谱柱的故障诊断与维护（二） 宽 峰* 在进样口到柱或柱到检测器之间，使用细的短的连接管 * 保证所有的管路接头都使用正确 * 用小体积检测池 * 减少进样量 Extra column dispersion looks like this....On one system with one column, the peaks are nice and sharp. On a different system or with a different column or chemist, the analysis looks like the one on the right. Tubing is the number one cause of this band broadening from dispersion. Make sure you are using short, small id tubing between the injector and column and between column and detector, eliminating as much additional dead volume as possible. If using a different system in a different lab, do not be fooled by the length of the tubing alone. Check the ID! Make sure all connections are made with matched fittings, as we will see later. This includes unions, column end fittings, and injector/detector fittings. Check to volume of the detector flowcell to make sure it is compatible with the column. Smaller id columns require smaller flowcell volumes if you would like to maintain the efficiency of the separation. Make sure your injection volumes have not increased due to a software programming error in the method. Check the microliters injected. Also check the sample concentration to make sure it is not 10 or 100 times more concentrated than you think, the attenuation will give this one away.柱外体积效应的影响压力I. 不进样时柱压连续升高- 泵密封垫- 流动相有颗粒- 流动相溶解性- 流动相的不稳定性 (聚合)- 形成柱死体积 (与使用条件有关)II. 进样时压力升高- 样品有颗粒- 样品在流动相中不溶- 样品组分与固定相不兼容保留值漂移I. 所有峰都向低保留值方向漂移（酸、碱、中性化合物）- 键合相流失- 流动相不稳定 (可能性较小)- 溶剂输送系统 (流速变化)II. 所有峰都向高保留值方向漂移- 在水/有机溶剂的混合体系中，有机溶剂含量减少- 柱改变 (可能性较小)- 溶剂输送系统 (流速变化)III. 离子型化合物的色谱峰的保留值漂移-流动相中挥发性组分损失 (离子强度, pH 漂移)- 柱改变 (键合相或污染)保留值漂移 I. 与流动相有关的问题- 使用新鲜的流动相?? ?pH?? ?电导?? ?色谱性能测试II. 与色谱柱有关的问题- 测试新柱- 用标准的测试混合样测试新柱- “清洗” 色谱柱后再测- 考虑样品基质与使用条件对柱稳定性的影响良好的柱使用规范??在使用前过滤溶剂 完全润湿在运输中变干的色谱柱 了解溶剂对样品的溶解性及分离的影响 对含有保留性较强的杂质组分的样品要进行预处理 清除柱填料的局限性 ?? pH ?? 温度 ?? 化学兼容性 使用新鲜的水溶液，并考虑使用生物稳定剂（如叠氮化钠） 定期用强极性的溶剂清洗色谱柱 l储存色谱柱时，应冲净缓冲言，并用有机溶剂饱和色谱柱（乙腈） l避免外力损伤色谱柱