Dear Sutapa Patra thank you for asking this interesting technical question. As synthetic chemists we are not really specialists in this field. However, I would like to recommend to you the following potentially useful references which might help you in your analysis:

A modified data normalization method for GC-MS-based metabolomics to minimize batch variation

Article A modified data normalization method for GC-MS-based metabol...

and

Guide to achieving reliable quantitative LC-MS measurements

https://www.rsc.org/images/AMC%20LCMS%20Guide_tcm18-240030.pdf

Both papers are freely available as public full texts and can be downloaded as pdf files. I hope this helps. 😊

SIM is a specific/selective mode - don't try to determine concentration based on normalization method. Every compound is ionized differently, every fragment ion will give much different abundance depending 9n type of compound.

Regards

GB

Actually the mathematical equation is differ from the scope of analysis. There are no specific mathematical equation to do so. However, there are several literature are available related to your desire. You may have a look on this:

Article Good quantification practices of flavours and fragrances by ...

Article A modified data normalization method for GC-MS-based metabol...

Nice question