HPLC Baseline Drifting down at start of each injection


Please forgive me as I am still new to this but I have not found the answer to my question.

After injection, the baseline drifts downward but it still shows the peaks. The mobile phase is fresh, the column is less than 6 months old. I just replaced the Deuterium lamp. Is there somewhere else I should start looking to hopefully resolve this issue? Please let me know if you need any more details to possibly help me out.

Thank you very much for any help, I couldn't do what I do without you all


  • Hi

    After replacing d2 lamp, you should do wavelength calibration..

  • Check above detail info to see other options.

  • Is there any noise coming out from system?

  • Hello,

    I apologize for the delay in responding, you know how lab life is. I tried to look around to see how to calibrate the wavelength but was unable to find it with a quick search. Our Lab Advisor software is not working and my boss does not want to update for now. Hopefully there is still a way to do that.

    Also, yes there is some noise. I can try to get you a picture some time but am not able to at the moment.

    I appreciate all of your help.


  • Hi

    Just some more questions:

    Is this a new problem or something that you have seen on this method since you started to run it?

    Is this a gradient or isocratic HPLC method?

    What wavelength are you measuring when you see the drift?

    Have you tried to flush the HPLC system, to ensure that the flowpath is clean from the mobile phase bottles all the way to the detector?

    Is the baseline stable before you inject a sample?

    Is the pressure stable during the run (isocratic method)?


  • Hello

    This is a new problem. We run an isocratic method, and I will have to pay attention to the pressure next time I run. We only run a few times a week at the most. The baseline is stable until I inject our sample and it starts to drift down afterwards. We run at 275 (the bigger problem) and 254. I have not flushed the system but I will put that on my to-do list.

    Thank you so much


  • Here's an update for anyone in the future having this issue.

    There was something in the ALS that was causing the baseline to drift after injecting. I also performed a wavelength calibration as ISH had mentioned to do and flushed the entire system. After the combination of these, the baseline is much more steady and we are up and running. Thank you ISH and Andy Wright.

  • Glad to hear that you have the problem solved!

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