Chromatography Forum

Hi everybody,

Does somebody have experience with ethanol in blood analysis with GC ?

I am trying to develop a method based on multipoint calibration curve 0.5 - 3 promille, n-propanol as ISTD (is 1 promille a good concentration?), input of 400 ul blood and 400 ul internal standard. Ret. time for alcohol is 15 min, for ISTD 19 min.

Should I use Na-sulphate in the vial ? Total blood or serum ?
I have problems with the linearity of the curve ...

Any comments, ideas ?

Thanks,
Jack

Most analyses for ethanol in blood is done by headspace analysis. There are many articles on this in the literature.

To do this the old fashioned way by packed column GC you must separate the red cells from the plasma and inject the plasma onto a porous polymer column or a carbowax coated carbopack B or C column.

The internal std is added just before injection.

I hope this helps.

best wishes,

Rod

Hi Rod,

I am using headspace GC (Konik-Spain), N2 as carrier gas.

If you have some method which is proved to work accurate, please post it or send it to me.

Thanks ...

Police laboratories in the US have done a lot of research on this issue.

In particular the State Highway Patrol of the state of New Jersey comes to mind.

Perhaps a search on the web using these key words or in toxicology journals might be of some benefit to you.

I do not have the articles at hand.

best wishes,

Rod

Journal of Forensic Science, VOl 29, NO 4 October 1984 pp1038-1044

D.S.Christmore, R.C.Kelly, and L.A.Doshier

Hi Jack (don't say that around an airplane though), but great name for asking about blood alcohols. We assay for ethanol in personal care products also using n-propanol internal standard and dilution with water, but our retention times are about 2 min for ethanol and 4 min for n-propanol on 15 m x 0.53 mm Nukol capillary column at 40C, significantly faster than yours. We keep injection volume to 0.5 ul due to expansion of water.

Thermo have published an Application note for Static headspace Alcohol in blood analysis that is freely downloadable
Alcohol