Hi Paulina,

two techniques are mainly used in the GC for quantification:

1. External standard (ESTD)

2. Internal standard (ISTD)

The first technique is used if, for example, there is no space in the chromatogram for an internal standard. It is quite reliable, but only when using an auto-injector. Manual injection is ruled out because the injected volume varies too much. In this technique, the concentration of substance is plotted against a peak area. As a rule, a straight line is obtained from which the amount of substance can be read off for a given peak area.

The second technique also works with manual injection. You then look for an internal standard substance that eluts near the substance to be analyzed and shows a similar response factor. Here, the peak area ratio between standard and analyte is plotted against the quantitative ratio between standard and analyte.

Here are (I hope so) some helpful links:

https://www.agilent.com/cs/library/usermanuals/Public/G2070-91126_Understanding.pdf

https://hplctips.blogspot.com/2014/03/external-vs-internal-standard.html

http://jan.ucc.nau.edu/~jci5/courses/chm320/Lecture%207%20Ch%205b.pdf

http://dpuadweb.depauw.edu/harvey_web/etextproject/pdfFiles/Chapter5.pdf

http://depa.fquim.unam.mx/amyd/archivero/calibracionanalitica_6118.pdf

http://www.google.de/url?sa=t&rct=j&q=&esrc=s&source=web&cd=34&cad=rja&uact=8&ved=2ahUKEwj5nsbmq8zgAhWRPOwKHaOJADY4HhAWMAN6BAgBEAI&url=http%3A%2F%2Fwww.sapub.org%2Fglobal%2Fshowpaperpdf.aspx%3Fdoi%3D10.5923%2Fj.jlce.20150301.03&usg=AOvVaw2r5qINQcrtwTZY7cGu8E9E

Best regards

Markus

Please look at the following below links which may help you in your analysis:

https://www.ncbi.nlm.nih.gov/pubmed/12356280

https://dc.etsu.edu/cgi/viewcontent.cgi?article=3593&context=etd

https://pdfs.semanticscholar.org/f552/fb354ce422a30dfc7718a5e48228d9fed6d4.pdf

Thanks

Comparison with standards best method, another based on NIST library

Thank you Markus Christ the links have been very helpful!

Thank you Isam Eldin Hussein Elgailani that thesis is going to help me soo much.

Article The quantification of citral in lemongrass and lemon oils by...

I think this is the thing you looking for.