Signal to noise problems

<p>Hello!</p><p></p><p>I have a sensitiviy solution that is 0.05% of my standard concentration. It has been injected fine and signal to noise has been around 12 all the time. Since last week we are not getting that result anymore. Baseline is a little bit noisier so we have done the following:</p><p></p><ul><li>Flush the UPLC (Acquity UPLC) using 50/50 IPA/Water, then ACN
</li><li>Changed column to a new one.
</li><li>Turned off detector module and back on.
</li><li>Re-prepared mobile phases (is just filtered Water on A and ACN on B, but still)
</li><li>Checked lamp hours (around 480).
</li></ul><p></p><p>What else could we do? thanks!</p>


  • Hi,

    how do you calculate signal to noise rat  ?i mean manual or by Empower?is this possible for you to upload a chromatogramme .

  • Hi!

    Thank you for answering, I was calculating it using Empower. Right now the baseline improved on its own, we flushed the cell some more, thanks!

  • Hi

    Use the empower to calculate the signal to noise ratio...the EP method needs to be activated on the system suitability tab in your processing method, using Peak to peak noise. The detector /drift setting ask for a segment width(which is calculated as follows:20x60x width at 50%).Select a portion of baseline noise that is = or greater than the segment width in seconds and check your signal to noise.


    Janita Bawjee

    Senior Validation Chemist