Why I cant see my PDA trace?

Dear All,

I am not able to see PDA trace while running the prep HPLC system.  I have managed to check the flow, detector lamp and other checks, all are ok. I have cross checked my detector settings, the 3D signal is enabled and spectra collected from 190 to 800nm.  However, the collected signal is like a flat line?

Please can someone provide any tips?

Kind regards



  • Have you acquired an injection with your sample in it? Im pretty sure you have to extract the signal at a certain wavelength to get useful chromatography. What wavelength does your active elute at? You could add a derived channel of Single Wavelength and a processing method to your method set. Then open up the channel with the method set, apply method set and view the extracted chromatogram at that wavelength. You can interactively change the wavelength using the slider bars in review as well as save chromatograms too. 
  • Thanks for your quick response.  I have injected a 10mg/ml standard solution, the recommended wavelength is 243nm.  Though I extracted chromatogram at 243 or 210 or 300nm or any wavelength between 190 to 400nm wasn't shown any peak/noise.  This means I guess either detector settings or some other issue

  • Is PDA a ticked property in the project? Is the resolution in your PDA processing method set to 1.2nm between the data points? Is your sampling rate appropriate? 
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