Processes taking place in the graphite tube: Anion and matrix effects in atomic absorption spectrometry. II. Determination of mercury

The atomic-absorption behaviour of different mercury compounds in the graphite tube was investigated. It was established that in the case of water-soluble volatile mercury compounds (nitrate, chloride) there is a considerable mercury loss even during the drying of the drop. The mercury can be determined, however, in the form of colloidal mercury sulphide atca. 200° C and with atomization at a relatively low temperature. Some interferences limit the use of the method in practice (compounds evaporating together with the mercury, presence of other metals producing sulphide precipitates) but the use of mercury dithizonate overcomes these limitations. The method was applied for determination of the mercury content of waste water and waste water sludge.