Hi, some sort of silicate probably. Use digestion mix with HF in addition.

I think it could be for the mixture of acids and peroxide that you use, I have used only nitric acid or the coambinación 5 ml of nitric and 5 of peroxide for plants that in this case would be the distillery materials, and I have not had that problem, test and instead of 0.2 g, I think you should place 0.3 g of the sample. Or simply digest it with nitric acid 0.3 g of sample plus 10 ml of nitric. On the other hand, you do not say what was the programming you used in the microwave.

Hi,

It looks like the sample hasn't fully digested and there is a high TDS%. I imagine when still warm and just out the microwave the particles are suspended and as they cool they settle to form precipitate.

I run a similar method for trace metal/mineral analysis but with 0.5g animal feed, 8ml of 69% Nitric acid and 2 ml of 30% H2O2 , leave for 15 mins and then microwave digest. Once digested, samples are diluted with DI water to 50ml. We dont experience this problem. However, the higher the dry matter of the sample the larger your 0.2g sample and TDS% will be. We have found in the past samples with a higher dry matter need further microwave digestion or left for longer in the nitric before.

Microwave can only assist digestion and do nitric acid is better.

There are many mixtures that can be used for digestion, the mixture will depend on what type of component we want to digest, certainly the nitric acid used is the best, best regards

Hi,

Is the haze/precipitate settled on the liquid level of the digestion tube, which looks like translucent fat?