Abstract
Mercury in geothermal water samples, pretreated with ozone, was subjected to reduction-vaporization by use of tin(II) chloride. The mercury vapor was concentrated with a porous gold collector. Afterward, mercury vapor which had evolved from the heated collector was determined by cold vapor atomic absorption spectrometry (CVAAS). By using ozone as pretreatment agent, the time for the decomposition could be shortened and the blank value of mercury from reagents used was reduced. The permissible amounts of sulfide and thiosulfate ions, the main interference ions in reduction-vaporization of mercury, were 25 and 100mg dm-3, respectively. It means that the present method provides an improvement in the permissible amounts of these ions by several hundred times in comparison with the methods using no ozone. Ozone was also found to be effective as the pretreatment agent for organic mercury. The present approach was proved to be satisfactory as the pretreatment of the quantitative analysis of ultra-trace amounts of total mercury in geothermal water samples.
