derivatization method for carboxylic acid ?

[guoyang]

Hi, everyone!
I have two compounds. Because UV absorbance of two compound is very weak, I want to try GC derivatization method. One compound contains one carboxylic acid and two carbonyl group, the other compound contains one carboxylic acid and two hydroxyl group.
Does anybody have good derivatization GC method? Thanks!

[Schmitty]

I have good luck with BSTFA and BF3.

What is your sample? Is it in an aqueous solution?

[Consumer Products Guy]

I have good luck with BSTFA and BF3.

What is your sample?

I think Schmitty means BSTFA and BF3/methanol to make methyl esters. We've also used H2SO4/methanol to make methyl esters.

In the soaps field, methyl esters is the most used technique for this.

[chhubert]

You may use (trimethylsilyl)diazomethane solution for simultaneously derivatizing the hydroxyl and carboxylic acid groups, with the former being changed to OTMS and the latter being methylated to methyl ester. No reaction is expected for carbonyl group. Easy to use, the chemical in ether or hexane could be purchased in Sigma/Aldrich.

Hubert

[guoyang]

Thank you very much !