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：弯曲、跌落或将接头拧的过紧
Now lets cover some good column practices that will help you to increase your column lifetime. 
Filter solvents before you use them.  The column is the HPLC system’s best filter, so make sure the column isn’t performing this task. 
Pretreat samples that contain strongly retained compounds of no interest.  This means to remove any sample matrix, or contaminants, or incompatible analytes to the method/column.  Solid phase extraction is good for this clean up. 
Avoid extreme column temperatures, greater than 60 degrees, or check the vendor limits.  Some columns are now made for higher temperatures. 
Flush/clean the column often with strong solvents.  Also use gradient cleaning. 
Keep the mobile phase pH between 3 and 7 unless otherwise indicated by the column vendor (polymeric phases).  If it is necessary to do this, use a precolumn and expect a shorter lifetime. 
Always use fresh buffer solutions and aqueous mobile phases or treat them with sodium azide, this can be dangerous.  Water solutions grow "bugs" or bacteria, these will contaminate and permanently modify the stationary phase. 
In line with the last point, prepare columns for storage by rinsing all of the buffer out of the column, then store in the appropriate solvent, at least 50% organic.  This will keep bacteria from growing on the column.  Make sure to rinse the buffer off first and with water, as many buffer salts precipitate in 100% organic.  Then cap the column tightly to keep air out. 
Avoid physically mishandling the columns.  This includes banging, dropping, overtightening fittings, and hitting your lab partner

预柱与保护柱

Here is a schematic illustrating the difference between a pre-column and a guard column.
A pre-column is an in-line filter device for filtering solvents prior to the injection valve where the sample is introduced.
A guard column protects the analytical column from sample contaminants that are strongly or permanently retained by the column phase.