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- Posts: 31
- Joined: Tue Sep 13, 2016 10:52 pm
I worked before in LC-UV and GC-FID and it worked quite easy for quantitation as I just inject my three or four standards at different concentrations and then take each area againest concentration and plot external calibration curve to be used later for quantifying these three unknown compounds in my samples using UV based.
However, this is my first time I introduced to LC-MS or GC-MS ( actually I have not seen LC-MS yet but I would like to learn it).
I have read a lot in LC-MS instrumentation,
And how ions can be formed by API or EI etc but I still not sure how to figure from where I can quantify my compound? Do I use TIC ( i feel it is like the chromatogram obtained by LC-UV) but some people sayed this is not because TIC is a summed of all ions scaned and some mentioned SIM for quantitation( i feel this same as TIC but it is like deleting some peaks ) but a gaing do I just seperate my compound at TIC to look as resolved base line peaks then i just use their area to measure their concentration? What if not seperated do i need to seperate it to baseline?
In some books and papers I read they show two chromatogram one is intensity vs time and by pressing in each peak you will see spectra of intensity/ abundant vs m/z
Some people said use TIC for quantification
Some said use area of peaks from SIM only
Other i saw in papers never used this but they use m/z ratio , other used base peak , else used base peak divided by molecular ion.
Could you please illustrate how to quantify area? Unfortunately i am struggling to find any paper or book to expline this like what book do when they talk about UV based detection.
Thanks and I appreciate your valuable time.
Fraich