Hello! I hope that there is anybody, who can help me, even though my problem looks trivial.
I am dealing with complex mixture of hydrocarbons (prevailing are cyclanic C10 hydrocarbons). I have analyzed them by both GC/MS and GC/FID using the same column. There are many isomers and I need to separate at least molecules with one and two rings. This information I obtain from MS, but I don't have standards to find the response factor for molecular ion of particular components. For that I think, I could use the data from FID. However I am not sure, how to do it correctly. (Shall I use areas or percentage areas from FID? ...etc). Thanks for all suggestions. DK

Here we usually use FID for the quantitative part, FID response should be more consistent with similar compounds.

Purify the mixture by column separation in lc, identify them with ms and nmr, get the rt's with gc/fid, make your cocktail with know masses of known compounds, and do gc/fid. Quite a large project.

If you can quantitate them with FID, you should be able to do the same thing on MS.

This is how I would approach the problem. Build your own 'standards' by using the FID responses to assign quantitative values to the component(s) of interest. Using these values, build an MS calibration table with the correct masses for the compounds of interest. Probably all systems have the ability to use a RF from one compound to quantitate another.

I recently did some work analyzing paint thinner materials on our MSD, so I see your problem. I mostly used the total 50-550 amu response to do the quantitation, but I also used the 57 ion from the PT standard to quantitate the contribution from 57 in my samples. It may not be a perfect solution, but you may be able to refine it as time goes on to a system you can live with, or you can find a way to physically separate the material.

One thing for sure--you won't get bored.