Quantify Silicon in Silicone Oil by ICP-OES

Advice By Paul Gaines, Ph.D
I have tried to quantify silicon in silicone oil by ICP-OES. To reach sample digestion, the mixture HNO3 (4 mL) + H2O2 (2mL) +HF (1mL) is used. Digestion is microwave assisted. Weight sample is 100 mg where only 3% is silicone oil, 97% is polymer. In spite of getting clear samples, silicon results are lower than real values.
I've browsed on the Silicon element in the periodic table and found a sugestion to digest silicone oil with conc. H2SO4/H2O2 followed by cooling and dissolution of the dehydrated silica with HF. May I perform this task on microwave?
Are there special quantities and procedure to make it right? I appreciate your attention.

Best regards, Dr Marilene Alves
Dear Marilene,

My experience with silicone oils is primarily with direct analysis after pretreating the sample with alcoholic KOH to destroy volatile oligomers. I believe that your digestion procedure can be performed using your first approach but should incorporate a closed vessel digestion. I would like to suggest that you contact CEM concerning the possibility of using sulfuric and peroxide or the issue with your current method ( elaine.hasty@cem.com).

If you still have questions or problems please contact me. Best to you.

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Serving you in chemistry,
Paul R. Gaines, Ph.D.
CEO of Inorganic Ventures

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