Chromatography Forum

i'm using shidmazdu gc-14 b with fid detector. what is meant by uV(X100000) in y-axis of the chromatogram? is that intensity or unit volume or what??? is there any specific unit for it ???? as shown in the picture
http://s825.photobucket.com/albums/zz17 ... tled-1.jpg

one more thing, after i do the integration for sample peaks, i got a table of retention time and height. i just wanna know is there any specific unit for that height???? like centimeter/cm, metre/m etc. ??? or i just unit less????

please help me


thanx

uV stands for micro-volt. The first u should be the Greek symbol micron. It is a measure of the electronic signal produed by the FID's electometer.

Peak heights are also in uV, or mV, depending on the scale that you have set.

You should perhaps consider measuring the size of the peaks by their area rather than their height. Height is proportional to quantity only if peak widths are constant, which they seldom are.

Googling gas chromatography and detectors will deliver all sorts of useful knowledge.

Peter

I've always thought that FID signal is usually measured in pA because this resembless the principal of operation of FID.

pA is a measure of the flow of electricity in the detector.

microvolt is the voltage range of the electrometer used in the detector.

Different ways of measuring the same physical phenomenon.

How do YOUR engineers measure a flow, by flood stage, or by how many cu ft of water as passing through the neck of the river?

same principle.

Best wishes,

Rod

pA is a measure of the flow of electricity in the detector.

and that's what we really want to measure, at least ChemStation FID chromatograms have signal axis labeled with pA.
And you configure FID offset in 6890 in pA as well.

We have discussed it earlier (viewtopic.php?f=2&t=19223&start=0).

In fact this unit does't need to be expressed in pA, µV, mV or anything.
It would be sufficient to label signal axis in "units", "counts" or anything else.

MfG