[rhyno-of-the-port]

Hey guys, what should be considered when choosing suitable internal standards for GC?
I've already got that it should have predictable area and retention times so any anomalies can be detected, and that obviously conc should be known and kept constant.
Anything else?

[JGK]

What type of GC separation are you performing?

If its based on boiling points (bp) you should select a STD which wont interfere with your analytes and is within the bp range of those analytes.

To be honest, I'm more familiar with the use of internal STDs (IS) in bioanalytical LC (or LC-MS) where the IS is either a stable isotope variant of the analyte or a compound of similar structure. In these situations, the primary function of the IS is to compensate for variations in extraction efficiency.

[NP1957]

I think so, it depends on the components of sample you are going to analyse.

Basically, the internal standard should be the compound which is not co-eluted or overlapped with the sample components.

In my experience there is some reason such as the internal standard should be sensitive with the detector. I have developed the GC method for organochlorine pesticides analysis using an electron capture detector. I chose pentachloronitrobenzene as the internal standard.