Quantify Silicon in Silicone Oil by ICP-OES

Dear Dr Gaines,

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 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

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 (

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 & Fellow Chemist

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