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methanol content
Posted: Mon Apr 11, 2005 8:56 am
by N.V.V.S.S. RAMAN
Hello friends,
When I analysed methanol residual solvent I am getting 200 ppm while using DMA as diluent
, whereas I am getting 4000 ppm if I use benzyl alcohol as diluent
. Can any body explain
Which method I have to follow
Thank you
Raman
Posted: Tue Apr 12, 2005 12:50 pm
by Mark
I have just started using benzyl alcohol as a matrix for headspace analysis and have seen some residual methanol in the benzyl alcohol. Have you run a benzyl alcohol blank?
Regards,
Mark
Posted: Tue Apr 12, 2005 1:35 pm
by N.V.V.S.S. RAMAN
Yes Mark
I tested benzyl alcohol and found no methanol contamination. We checked with GC MS also
Raman
methanol measurement
Posted: Tue Apr 12, 2005 6:23 pm
by chromatographer1
There are several possible causes for this discrepancy of methanol content measurement. You must eliminate them one by one.
Is the methanol real or artifactual is the primany question.
The DMA (dimethylacetamide?) may react or may have a contaminant that reacts with methanol or blocks the transmission of methanol to the detector in some manner in the matrix you are testing.
The benzyl alcohol may cause or permit a reaction that produces methanol in your primary matrix.
Try changing conditions and see if the data are reproducible
Try a different solvent that is not alcoholic or a proton donor and is not basic, a proton acceptor, as well.
Toluene, Dimethylsulfoxide, dioxane, methylethylketone, ethylene glycol dimethyl ether are some possible alternatives.
A little more information about the application might be helpful to the forum to assist you in your search for answers.