Methanol as a solvent for ICP-OES

Hi,

I don't expect much problems with the icp-oes measurement. However if doubts are about the chemical stability of the measured elements it's maybe better to dilute with at least 2-3% HNO3 solution where then the pH going below 7

Be aware that carbon based spectral interference are highly present in the spectra and check this with confirmation wavelengths.

Hi Edgar, 

Thank you so much for getting back to me. 

Are there any safety concerns with adding HNO3 to an aqueous/methanol solution of approximately 90/10?

This has been raised as a potential safety issue.  As we don’t have any experience with this, I would appreciate any advice about additional safety protocols with this.  Or is this a common sample prep method where the water concentration is high enough to quench any rapid reaction?

Cheers, 

Nathalie

Hi Nathalie,

yes, your right. Direct transfer of concentrated HNO3 to concentrated alcohol give an big exothermic reaction. 

If the alcohol or HNO3 is buffered with water, like the 90/10 from your explanation then the reaction goes slower (or doesn't start?) 

From my experience with HNO3 addition in wine or light spirits no big exothermic reaction started, only a bit warm. But always transfer the HNO3 in the safety cabinet and wait for a time and feel if the tube or beaker is (still) hot. If not then the reaction is stopped or negligible.

Hi Nathalie,

yes, your right. Direct transfer of concentrated HNO3 to concentrated alcohol give an big exothermic reaction. 

If the alcohol or HNO3 is buffered with water, like the 90/10 from your explanation then the reaction goes slower (or doesn't start?) 

From my experience with HNO3 addition in wine or light spirits no big exothermic reaction started, only a bit warm. But always transfer the HNO3 in the safety cabinet and wait for a time and feel if the tube or beaker is (still) hot. If not then the reaction is stopped or negligible.