Column care and regeneration

When not in use, HPLC columns should be kept filled with solvent, air-tight and free from vibration. Water is generally regarded as an unsuitable conservation medium in view of potential fungal growth. Salt solutions (buffers) may crystallize and cause clogging. 

Do not forget to label the column with the type of mobile phase. 

The following solvents are consecutively pumped through at a rate of 1-3 ml min  

75 ml of 1-5% aqueous acetic acid if basic impurities are present  

75 ml of hexane (if hexane is subsequently used for chromatography, otherwise stop at ether). 

If the separation performance should decrease as a result of the silica adsorbing too much water, the latter can be removed by chemical means the reagent either being self-formulated or bought as a ready-made version (Alltech Associates, Deerfield, Illinois, USA). 

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