Chromatography Forum

Does anyone out there have any experience performing the old USP procedure to assay the amount of iodine in thymol iodide? We use the raw material in one of our finished pharmaceutical products and are trying to assay this to verify the results obtained by the manufacturer.

I can't get the stuff to carbonize completely and am not having any luck getting in touch with the manufacturer to pick their brains. I am in the US and they are in India and they are obviously such a good company to do business with since they won't get back with me.

Unfortunately, I don't make the decision on who we do business with, but I do have to test the product.

Please help with any tricks to get this stuff to work.

Yeah we are testing thymol iodide too, and I'd be willing to bet that we get it from the same supplier in india. We had been having trouble with the manufacturer method. It is wholly outdated, and I think it's based on USP 9. If you have access to a dionex or any other type of IC, I would try heading down that path. Our validations department is currently developing a method for IC, and from what I've seen it looks a whole hell of a lot easier than that titration method.

Hi

One trick that may help: Sometimes carbon particles are trapped in fused alkali carbonates, phosphates or similar resulting in non carbon free residue. Adding some hot water to dissolve them and reignite may help.

Seems like method is not in USP anymore so care to share details in sample work up?.