Chromatography Forum

I've had difficulty testing for ethylene glycol in urine/serum. Does anyone have a procedure they'd be willing to send me? rubyfan@yahoo.com

Presently, I am getting false positive on known negative samples of urine. My procedure is as follows:

Add 100 microliters urine or serum to test tube. Add 700 microliters acetonitrile. Add 100 microliters 2,2-dimethoxypropane. Add 100 microliters of phenylboronic acid solution (20 mg phenylboronic acid in 10mL acetonitrile). Supposedly, the ethylene glycol is converted to 2-phenyl-1,3,2-dioxaborolane. However, I find that even known negative urine samples are testing positive (albeit at a very low level, ppb). Are all glycols probably being converted to this 2-phenyl-1,3,2-dioxaborolane? If so, is there a procedure that is specific for ethylene glycol? I want a test that I am confident in, I don't want all random glycols to be converted to this derivatization product.

Thanks,
Aaron

akthmps,

I don't think the boronic acid will interconvert various glycols to EG. More likely is that the dimethoxypropane might have trace contaminants that hydrolyze to EG and maybe this is interfering with your analysis?
Just a random thought,
Regards,
Mark

I have a non-derivatized method that does not derivatize the ethylene glycol. I have not tried the method but the chromatogram looks good for the other glycols including GHB. Give me a fax # and i will foward you a copy.

OK, so this really isn't a consumer product. USP uses DB-624/SP-624 type capillary for glycols and glycerin, non-derivatized (see glycerin for DEG and related materials), peaks are sharp. What levels are you looking for? I might also try dissolving sample in pyridine or DMF and making trimethylsilyl derivatives, and using a nonpolar capillary.

To measure ethylene glycol in trace amounts that akthmps is most likely trying to do from URINE and BLOOD is a real nightmare.

There are so many decomposition products that can be present after GC injection, it is no wonder that false positives occur. And then you have a dirty injector that just loves to adsorb EG.

I think the best technique would be liquid chromatography. There are high carbon load reverse phase columns that do a good job with EG. Given that there still may be interferences giving a false positive, I would suggest a two dimensional technique using a RP and an Amino column might be a good direction to investigate. Certain pharmaceuticals are tested for EG content.

Does anyone have any toxicology journals/articles that address this analysis? I would think this measurement would have been addressed long ago.

Enzymatic analysis might a direction to search. Sorry I cannot be of more assistance.