Chromatography Forum

I have questions about the response of the FPD and I am wondering if there is an FPD user that could provide me with further information. For example, does the FPD respond to nitrogen containing compounds? Does it yield negative peaks for other hydrocarbons or does it simply supress the response for sulfur/phosphorous when they co-elute with hydrocarbons. How much of some hydrocarbon, say pentane, can you shoot before you see a response?

Thanks in advance.

Other than the PFPD I haven't heard of using it for Nitrogen. In my experience it doesn't give negative peaks for other hydrocarbons. The FPD usually gives what I describe as normal noise, it jumps up and down a lot. When you look at the baseline closely it seems very noisy. But when you run your OP pesticide on it the baseline looks like a very smooth flat (usually) baseline next to your peak. A lot of this is dependent on the compound you are analyzing, the concentration, and the detector conditions itself.

I don't know about suppresion due to co-eluting compounds. I don't think I have seen it though.

LocoLobo,

Do you mind contacting me through the e-mail address on my web site? I would greatly appreciate the opportunity to discuss this with an actual user.

Best regards.

Not used an FPD for years however I agree baseline is usually noisier in appearance than other detectors. Standard FPDs are used for P, S and Sn with specific filters for each element. Response to Hydrocarbons and Nitrogen will occur because at a high enough level you will get some light emmission at the wavelength allowed by the filter. Rejection should be good, only example I have to hand, 1ul Acetone/oil 1:1 gives Acetone solvent peak of similar height to 60pg Dimethoate (Splitless injection) and no peaks for the oil. Trace from late 80s Carlo Erba GC with FPD-80