Abstract
Abstract With elemental, inorganic and organometallic mercury each having different chemical and physical properties, routes of exposure, and toxicological effects. The analysis of mercury species has proven to be critical in assessing their direct influence on the environment, predicting their transport behavior in several ecosystem compartments and in the decontamination of hazardous pollutant materials. Although considerable efforts have been made in recent years for mercury speciation analysis, the analytical methodology still needs further improvement to promote the analytical sensitivity of detection. In order to meet the request for investigating biological significance of mercury species, in this study, Hg2+ and CH3Hg+ were separated using a cation-exchange chromatography column packed with polyhydroxy methacrylate gel. After the chromatographic separation, on-line transformation of mercury species into gaseous products by UV/nano-TiO2 photocatalysis reduction device was investigated to enhance the sensitivity of detection and reduce the non-spectral interference resulted from sample matrix. In order to enhance the vaporization efficiency, the effects of acidity, amount of TiO2 and formic acid on the vaporization efficiency of Hg2+ and CH3Hg+ were investigated. Based on the experimental results, 100 mM formic acid and 3 g/L nano-TiO2 suspension (Degussa p25) were used to on-line vaporize two mercury species under UV illumination. With our proposed procedure, Hg2+ and CH3Hg+ in the column effluent can be on-line vaporized and determined by ICP-MS after the chromatographic separation without the need of conventional chemical vaporization method.