I need to analyze the alkyl distribution of Methyl Ester Sulfonate to know the molecular weight of my sample. I tried to use gas chromatography to do this. My method was to reflux the sample first using HCl and then extract the methyl ester with Petroleum Ether. Then, I diluted the extract with n-hexane before injecting it into GC. However, the result was not as expected. Now I'm trying to dilute the sample in n-hexane without extraction but the sample cannot be dissolved. Do you have any suggestion? Thank you in advance.
You could try 1:1 acetone/hexane as your solvent and sonicating/vortexing your sample.
Other than that you could evaporate your pet-ether extract to dryness under N2 and reconstitute with hexane.
How was your previous result unexpected? If you have a lot of non-target peaks you may have to perform a clean up stage or use a more selective detector.
Luke Gymer thank you for your answer.
However, I did evaporate the pet-ether extract before adding n-hexane.
My chromatograms showed very small peaks that I am not sure if the methyl ester was successfully extracted.
I tried to change the pet-ether with diethyl ether however, the peaks were still very small.
Any another suggestion? Thank you very much beforehand.
Agnes Veronica Victoria I have found a technical resource you might find useful:
https://www.restek.com/Technical-Resources/Technical-Library/Pharmaceutical/pharm_A024
You can use GC-MS to determinate the molecular weight of your sample. The pre-treatment firstly is to make sure all of non-volatiles compound and ions like Chlorine , etc. have been removed from your sample. To ensure, no site reaction can be happened you can use N2 or He as a mobile gas. In addition, the temperature oven should be set at boiled temperature range of solvent and your sample. Please use internal standard method to make easier quantification of your sample. Success for your research.
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