Decomposition and stability studies of methylmercury in water using cold vapour atomic absorption spectrometry

Abstract

The long-term stability of Hg²⁺ and methylmercury chloride (MeHgCl) and the decomposition of MeHgCl under various conditions were investigated. In the absence of light MeHgCl does not decompose to Hg²⁺, even in the presence of 25% acids, during a period up to 3 d. MeHgCl is not easily decomposed by heating in the presence of 50% acid concentrations; however, with UV light the decomposition of MeHgCl to Hg²⁺ takes place immediately, depending on the intensity of UV light. In the presence of SH groups (L-cysteine), partial stability and complexation of mercury was observed. For the long-term storage of Hg and MeHgCl at low concentrations, in addition to certain reagents, the material of the container is important.