methanol content

[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

[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

[N.V.V.S.S. RAMAN]

Yes Mark

I tested benzyl alcohol and found no methanol contamination. We checked with GC MS also

Raman

[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.