Sample Preparation

We have some polyepichlorhydrin elastomers which are thought to contain some trace amount of tin in the form of an organotin compound that was used as a catalyst. Can you recommend a sample preparation procedure for these types of samples?

I have a question about preparing sulfur-containing compounds. Because sulfur and bromine are both non-metal, how will they react, and what equation(s) might describe this reaction?

We have a number of solutions that were extracted from small river sediment samples (<50mg) using a sequential digestion. The extracts had been preserved in 0.5% BrCl or 5% aqua regia + 0.01% potassium dichromate in order to preserve Hg for analysis by atomic fluorescence. We want to try to determine the concentrations of other trace elements (particularly the lanthanides) by ICP-MS. We plan to evaporate the samples and make them up in 1% nitric in order to minimize the bromide and chloride interferences. Would this approach be suitable?

We're having difficulty analyzing Si when the concentration is above 1% using ICP. Can you recommend dissolution techniques for Si concentrations above 1% in metals, specifically without the use of HF?

We are trying to measure Br (bromine) by ICP-OES for samples in a PET matrix. The expected Br concentrations range from 1-18%, and do you have any recommended methods of analysis?

We're trying to find the best way to digest coal samples for the analysis of mercury, arsenic, and selenium. Our initial attempts led to poor recoveries, and now we want to try a microwave digestion approach. Do you have any suggestions?

Can you provide a tried-and-true preparation method for dissolving quartz powder?

I was wondering what would be a valid procedural method to adequately leach Silicon from a natural flake graphite (most likely in the form of SiO2)?

I am working on developing a method to analyze trace amounts of Hg in DMSO. My proposed specification level is 100 µg/g. I have an ICP-OES, ICP-MS, or CVAAS available for instrumentation. I'm not sure what I should do for sample prep, do you have any ideas?

I have been doing some method development on Sn and Tl in soils, and noticed that the recovery on various CRMs is very low. We've performed both both nitric acid and aqua regia preps. Can you offer any suggestions as to why we have low recoveries?