Chromatography Forum

hi

i was workin' on Fatty acid methyl esters n needed a GC analysis..
i used 2.5 macro liter (C14 FAME) as internal standard n 1cc hexane as solvent for 50 macro liter of my sample
now, i have the chromatograms and the peak area reports, but dunno how to calculate FAME content in %

actulay i tried a method described in EN14103 for biodiesel(FAME) which says:
%=sum(FAME peaks)/(internal standard peak)*mg IS/mg sample
i also know about using standard curves!!

but both of these methods seem pretty unaccurate to me
has anyone ever read an article about the method of calulation of chromatograms??? would u pls name the article, book, paper ...?

well,it seems no one knows the answer
or sth's wrong with my question

wrong with my question

You write like a child.


Your question is very basic. This book explaines the use of calibration curves, standard addition and internal standards. There is even a chapter on statistics in it.

http://www.thriftbooks.com/viewDetails. ... 0716744643

Your question is hard to understand.

Please just tell us what a macro liter is. I have no idea. Do you mean microliter?

What do you mean by a 2.5 macro liter?

Please describe your solution and how you prepared it.

Are you using an internal standard method or an external standard method?

You have not given us enough of the proper information for anyone to answer your question.

A chromatogram with a peak area report has to have a reference, a means of comparing the size of the peaks with a known peak of known concentration. Different FAME peaks will respond at different amounts of peak area for the amount of FAME present. Just having a peak area report does not give you enough information to do any calculations unless you choose to make assumptions.

Try asking your question again when you can give us more information about what you are doing.

best wishes,

Rod

...Try asking your question again when you can give us more information about what you are doing.

best wishes,

Rod

You (and other newer posters) might also want to read the sticky notes that provide guidance as to the best use of these forums and the information you should be providing to have a snowball's chance of getting a useful answer.

Maybe this article has a bit more info about the EN method...

http://www.bdal.de/uploads/media/CA-270 ... AME_01.pdf

This book explaines the use of calibration curves, standard addition and internal standards. There is even a chapter on statistics in it.

http://www.thriftbooks.com/viewDetails. ... 0716744643

Thank you for posting that link, that sounds like a good fundamental book to have in a lab library. I plan on purchasing today.

However, would you or anybody who reads this, happen to have a link to a website that gives a decent overview of the standard addition technique. My main focus would be on the benefits and drawbacks of this technique. I work for a Pharmaceutical manufacturer and use USP <467> frequently. I just want to better understand something I've already been executing.

Thanks

http://zimmer.csufresno.edu/~davidz/Che ... dAddn.html

(c) David L. Zellmer, Ph.D.
Department of Chemistry
California State University, Fresno
September 2, 1998


http://www.chemistry.adelaide.edu.au/ex ... td-add.htm

Department of Chemistry
University of Adelaide
Australia

Enjoy Charles,

Need the spreadsheet?


Rod