Chromatography Forum

Hi All,

I saw this column cleaning procedure from a vendor saying that I should clean my NH2 column using 30 column volumes of NaOH at pH11. The pH range of the column is 1-11...why does this not harm the column? I thought holding the pH at the limit of a column's pH range would drastically decrease its lifetime. Is NH2 different?

30 column volumes is not "holding" at that pH for very long. For a 150 x 4.6mm column at 2 mL/min, it,s just over 20 minutes. If the vendor claims an upper pH limit of 11, 20 minutes shouldn't kill it.