Irregular peaks

[Anna01]

HI!

I am new to this forum, but I take the chance.

I am developing a new method for an endogenous compound. My problem is that the peaks are quite irregular. The AUC seems quite consistent when running the same sample over and over, but i am still concerned that this would lower the sensitivity and precision. Both low and high concentrations peaks are irregular, and the "right" side is the worst. Some minor tailing iss also present. Assymetry factor about 2.

I am running a gradient program in ACN 15-70% (with 0,1% formic acid) over 6 minutes. The column is a C18 ID 2.1 50mm. Detector is a mass spectrometer.

Any clues? Suggestions?

Thanks!

[tom jupille]

First of all, an asymmetry factor of 2.0 is not "minor", especially in a gradient.

Secondly, with a mass spec, it may not matter, especially if you are getting reasonable quantitation.

It is difficult to say anything more specific without more details an, ideally, a chromatogram to look at.