Stability of Mercury in Plastic Bottles

Yanyan was curious about Inorganic Ventures' stability studies, wondering how stable a 10 µg/mL Hg solution would be after it's been kept in a plastic bottle for 5 weeks. He also wanted to know what the correlation between Hg concentration and stability would be.

	RE: Stability of Mercury in Plastic Bottles Dear Yanyan,      We have been measuring the stability of Hg at various levels in plastic for some time. We have found the stability of 10 ppm Hg standards in plastic to be good for at least 5 months in both borosilicate glass and LDPE in a water / 5% abs. nitric acid matrix. The one year date for testing is coming up during the first week in August [2002]. We expect to obtain results demonstrating at least a one year stability in the 5% abs. nitric acid matrix.      Be advised that we have seen instability at lower levels and have shown ppb levels to be stable in nitric acid for periods insufficient to obtain reliable measurements. We believe that HCl and Aqua Regia matrices are better for Hg than straight nitric acid. We've been able to demonstrate stability for 1000 ppb Hg in nitric acid, but have found a dependence upon the level of nitric acid as well as upon other elements present. For example, some organic acids mixed with Hg in nitric acid appear to reduce the Hg to the elemental state, causing the readings by ICP to be false HIGH. Thank you for your question and best of luck.     Paul R. Gaines, Ph.D. Serving you in chemistry