An improved digestion method for the extraction of mercury from environmental samples

Abstract

An improved digestion procedure for the extraction of mercury from environmental material is reported. The method involves the digestion of the sample at 60 °C with sulphuric acid-nitric acid (2 + 1), containing a trace amount of hydrochloric acid, and subsequent oxidation with permanganate and persulphate solutions. With this procedure mercury is successfully recovered from organic matter and resistant inorganic forms such as mercury(II) sulphide. Unlike digestion with aqua regia, this procedure is simple and safe, and is applicable to the digestion of a large number of samples simultaneously. The method can be adapted to the automated cold-vapour and flame atomic-absorption techniques and is therefore ideal for routine monitoring.