Chromatography Forum

How far should you integrate in your chromatography after the gradient is completed with impurity runs? Should you be concerned with peaks in the wash (i.e. max organic, end of gradient) or peaks after the gradient returns to equilibration?

A= 14mM buffer
B= ACN
Time %A %B
0 85 15
5 85 15
42 15 85
47 85 15
60 85 15

Would you integrate peaks after approximately 45 minutes? Why or why not?

Hello

You should integrate only peaks you're interested with.
Washing column with strong organic solvent is to remove strongly retained compounds (clean it) and not to resolve compounds.

Regards

Tomasz Kubowicz

As Tomasz said mostly with high procent of organics elute strongly retained compunds from column before next injection. But that doesn't mean those peak can be avoided.
Sometimes happens that in those strongly retained substances, one is that you are interested in or you should be interested in. You have to know which peaks you are interested in and which you aren't. That's why we use blank, matrix, placebo samples to see which peaks could be a potential impurity for instance.