TUV vs PDA Detector Question

Hello,A customer posed this question and would like it answered on the forum.The customer observes higher area count for their standard depending on whether they are using a TUV or a PDA; generally the TUV is higher. Is this normal? Thank you,Christine


  • Hello Christine:

    Can you get me a few details on the methods that you are comparing?

    However, in general the TUV operates a wider spectral bandpass (4 nm ) because its optics differs from that necessary to achieve a spectrum as is done in the PDA. The PDA, which by default, has a 1.2 nm bandpass, which preserves spectral sensitivity, unrequired in a TUV which measures one wavelength at a time. The effect is that the cumlative absorbance is lower. If you choose to set the PDA to output an additional 2D channel at a resolution of 4.8 nm as well as one 1.2 nm you will see the effect. This is why the TUV typically has a lower noise specification.

    Again without seeing the onstrument method for sure I cannot tell if this is the effect, that the flow rates and filter time constants are otherwise equivalent.

    The TUV and PDA operator's guides describe this in more detail and can be downloaded from the website.

    Best regards,


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