Alliance HPLC PDA 225nm : Disturbed baseline


I have a question about a recent problem which occur in our lab. 
This occur at the end of a samples set run (about 30 injections), The column has 900 injections. but only on few injections.

Here you have a superposition of 4 blank sample (ACN 28%). The chromatogram type is in black.

I don't know the reason of this problem. If someone can help me on this case ?
Thanks a lot



  • Hi Pad_CH.  Thank you for the question, and for including a snapshot of your data.  That's always helpful in helping to diagnose problems with a separation.  Unfortunately, we would need to know more information about your method to understand the situation and propose some solutions.  Please reach out to your local technical support specialist, who will be happy to help in further detail.  If you don't have a direct contact, you can access our resources through the website:

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