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Does gradient improves resolution?
Posted: Sun May 06, 2012 5:10 pm
by push
Does gradient improves resolution of chromatographic peaks?
Re: Does gradient improves resolution?
Posted: Mon May 07, 2012 12:30 am
by tom jupille
In general, no (there are a few exceptions, but they are very few). The major purpose of a gradient is to accommodate a range of retention too great to fit into a single isocratic run.
Re: Does gradient improves resolution?
Posted: Mon May 07, 2012 2:38 am
by Consumer Products Guy
The major purpose of a gradient is to accommodate a range of retention too great to fit into a single isocratic run.
I'm not going to disagree with Tom. I was going to post that we use gradient primarily in two instances:
(1) two or more peaks of interest have significantly differeing polarity and we'd like to do in a single injection (this aligns with what Tom posted)
(2) when we want to clean extraneous components/peaks off the column to determine trace level components in the subsequent injections (a clean up gradient)
Re: Does gradient improves resolution?
Posted: Mon May 07, 2012 12:20 pm
by tom jupille
You're right, but I'd put #2 under the heading of "collateral benefits". On reflection, I'd have to add the similar situation of sharpening up low-level late-eluting peaks. Either way, it's not a case of improving resolution.