Baesline drift in gradient method

[vanjas]

Is there any way that I can resolve the baseline drift in gradient method ?
The mobile phase A is 0.01M KH2PO4 and Mobile phase B is Acetonitrile.

Initial : A: B = 55 %:45% -> 40min = 30% : 70%.
Sample diluent : Methanol

Does the methanol make the drift ?
I heard that there is a way that can reduce the baseline drift by adding some kind of additives. But I don't remember..
If there is .. can anyone give me advise ??

Thanks for reading this matter and hopely you can give me some advise..

[Kostas Petritis]

It would be useful if you could add what detector you are using, and if UV, what is the wavelength?

[vanjas]

[quote="Kostas Petritis"]It would be useful if you could add what detector you are using, and if UV, what is the wavelength?[/quote]

I used UV- DETECTOR, AT 201nm.
will it be a problem? Thanks for your attention.

[Rafael Chust]

Dear Vanjas:

At this wavelenght, any organic eluent will cause baseline drift.

There are some low-UV HPLC grade solvents that you might try, but is it possible to increase your analysis wavelenght over 220 nm?

[tom jupille]

It is possible to "UV-match" your mobile phases by adding something that is UV-absorbing but unretained to the A solvent. A (very) small amount of nitric acid would work. Be aware, however, that it is not easy to get the level just right.

In most cases, the best way to handle drift is to simply ignore it. So long as it isn't really horrible and is fairly linear, most data systems do a good job of correcting.