Chromatography Forum

Hello,everyone,
I want to calibration my GC-headspace for ethylene glycol(EG),using FID, and DB-ALC1 and DB-ALC2. I know the molecule of EG is not volatile. My question for you,is if I can do that. I try many times, using different concentration of EG, and different temperature, but I can't catch EG. Maybe I must make a derivation?
Please if someone have experience, and can give me an advice, i'll be very gratefully. I have an GC 6890N Agilent and a headspace G1888. Thanks a lot

You can't do Ethylene Glycol by Headspace. Use direct injection, polar packing, no derivatization is necessary

I agree.

Allthough derivatization can be done, if your matrix is water it will be difficult. If not, then it is possible but the excess reagent will hide the EG-TMS.

If you try to make an acetate it will be difficult as well.

If you inject directly, be aware that a new injection liner may be required for every injection, depending upon the matrix you inject.

HPLC may be a better analytical choice.

best wishes,

Rod

What is your matrix and what levels of EG are you looking for?

The USP monograph for glycerin over the last decade (several versions during that time) have included different but similar assays for low levels of EG in the glycerin matrix using xxx-624 columns (USP deisiganted G43). Some of those years used water as the solvent, some used methanol. We were able to get pretty good results using those frequent modifications/versions.

thanks everyone for your advive. My matrix is whole blood. I am confused because I put first in a vial 250microliter of EG p.a.reactiv and 1750 microliter of tert-butanol as internal standard. On DB-ALC2, I obtain a very nice pik. After that I try to make a different concentration of EG, but I can not get it again. I start with concentration of 40 g/l......and maximum was 200 g/l. I can't see on the chromatogram how the concentration rise on the vial to another. Because that I am confused. I understand now from your advice that is better if I used a HPLC. Thanks again because you share with me your expericence.

My matrix is whole blood.

If your matrix is blood, then my guess is that this for for medical examiner/forensics, like for poisoning, correct? Then for legal confirmation you may need to use mass spec as confirmatory tool. For GC, mass spectrum of EG-TMS is more definitive than for underivatized EG. If you've already got a way to confirm EG identity, and just need a quantitative value, HPLC might be of interest as well.

Are there not published or official procedures for EG determination in blood/body fluids?

Determination of ethylene glycol in postmortem blood by capillary gas chromatography.

http://www.ncbi.nlm.nih.gov/pubmed/2709824

look what I found.

Rod

And

www.atsdr.cdc.gov/toxprofiles/tp96-c7.pdf

www.ncbi.nlm.nih.gov/pubmed/7176557

Rod

thanks a lot to everyone for your advices. I must do a derivation for EG. That I understood reading the materials. Thanks a lot Rod for your links. And if I use a GC/MS, I need to do derivation as well.
Best regards to everyone, Diana