Does anyone have experience with the Valco Pulsed Discharge Detector? I'm most interested in any use of the helium photoionization mode for hydrocarbons and/or fixed gases. Is it as linear as claimed and as sensitive? Pros? Cons?
thanks in advance for any replies
By Spencer on Friday, January 26, 2001 - 05:49 pm:
I don't know what its claimed linearity is, but in my experience, this detector has a linear dynamic range of at least 4 to 5 orders of magnitude. However, I've never done a comprehensive study. As far as sensitivity goes, I've have determined componenents down to about 30 ppb (injected solution) with splitless injection. Pros, it is a universal detector that is extremely sensitive. Cons, it will really tell how clean your gases are. Also, it probably doesn't make a good detector for above single digit weight percent determinations. This detector's sensitivity is somewhat dependent on how far you insert your column; you can empirically determine what works best. You want to use a discharge gas flow of about 40 mL/min to keep the analyte away from the discharge to prevent discharge electrode contamination.
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