By Anonymous on Friday, October 13, 2000 - 05:09 pm:
Trying to verify an assay on a two component solution using a CN column at 254nm. One component works fine but the second comes out about 20% high. We prepare the standard and samples from the same stock solution. The only difference is that the sample also has placebo added. The placebo gives no interference when run alone. Amy ideas out there?
By Uwe Neue on Saturday, October 14, 2000 - 12:08 pm:
First guess - a mistake. Second: a few questions: are you using a buffer in your mobile phase, and do all or some of your samples contain ionizable groups?
By Ian Dale on Friday, January 19, 2001 - 02:05 am:
is this an internal standard method?
Is 254nm the best for both - shouldn't make a difference unless there is a matrix effect on the sample not seen on the unknown.
What happens differently to your sample compared to your unknown?
Could there be some underlying peak in the sample not present in the standard?
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