Hello,

I need your advice as I am rather new to acid digestion techniques.

I am trying to build up an ICP method for the analysis of lithium. However, there appears to be interferences, probably due to the presence of glycerol in the matrix of the samples.

The sample is a liquid, clear, but concentrated in salt. The lithium salt is in a matrix made of 87% water, 6 to 8% glycerol and 0.06% sorbic acid.

To get more accurate results, I am thinking of digesting the sample (microwave digestion). We have a Mars 6, CEM oven.

However, having read few things on the subject, and without experience but one in explosives investigations, I wonder if the digestion of 1mL of sample (containing about 8% of glycerol) with 4mL of nitric acid 69% is safe? I would prefer not transforming the lab into a scene of investigations...

As the microwave oven heats and the vessels are under pressure, would you recommend such a thing?

Or do you have any experience or feedack with such manipulations?

What is your advice in such case? Should I operate it with a diluted solution of nitric acid?

Thank you very much for your help!