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gradient sloping downwards

Posted: Tue Dec 18, 2012 4:23 pm
by shadow
Hi and thanks in advance for helping out.
I am using acetic acid adjusted to pH 5 with ammonium hydroxide on A and 100% MeOH on B and I am monitoring at 230nm using a phenyl column. My problem is that the baseline slopes downward and I would like to correct for it and don't know how, any help would be appreciated.

Re: gradient sloping downwards

Posted: Fri Dec 21, 2012 6:50 am
by seamoro
your going to get slope when using a gradient you really cant help that. . You could try to raise your wavelenght higher to a region where there is less absorption but you may lose sensitivity or you could go isocratic

Re: gradient sloping downwards

Posted: Fri Dec 21, 2012 2:46 pm
by danko
Hi Shadow,

Acetate and 230 nm detection is a bad combination. Use another acid/salt instead of acetic acid/acetate.
What is the pH in you mobile phase by the way?

Best Regards