Determination of Mercury by Cold-Vapour Atomic-Absorption Spectrophotometry

摘要

This report describes an investigation into the determination of mercury, particularly in iron oxide and sulphide concentrates. The mercury is reduced by the addition of stannous chloride and carried by a flow of air to the absorption tube, where its absorbance is measured and recorded on a chart recorder. The optimum parameters affecting reduction and measurement (among them the concentrations of acid and stannous chloride, the time allowed for the reduction of mercury, the air flow-rate, and the sample volume) were established. In addition, a number of dissolution procedures in which use is made of various mixtures of acids (sometimes under pressure in sealed apparatus) were tested in an attempt to obtain satisfactory decomposition of samples and recovery of mercury. The possible interference from these acids and from thirteen probable interfering elements was also investigated. No severe interference was observed, and the method of additions was used to compensate for the minor levels of interference observed. Methods are proposed for the dissolution of samples and the measurement of mercury in amounts between 10 ppM and 0.1 ppM. The coefficient of variation at 3.4 ppM was 5.3%. 5 references, 7 figures, 2 tables.