A comparison of the extraction of mercury from sediments by using hydrochloric-nitric acid, sulphuric-nitric acid and hydrofluoric acid-aqua regia mixtures

Abstract

A study of the extraction of mercury from various sediments with hydrochloric-nitric acid, sulphuric-nitric acid and hydrofluoric acid-aqua regia mixtures is reported. The mercury in the extract is detected by using an automated cold-vapour atomic-absorption technique. Although greater extraction of mercury from sediments is possible with a hydrofluoric acid-aqua regia mixture than is possible with hydrochloric-nitric acid and sulphuric-nitric acid mixtures, the results, for the purposes of environmental surveys, are equivalent. The lower detection limit, better precision and simpler application of the methods involving the last two mixtures make them preferable. The hydrofluoric acid-aqua regia extractions were performed in a PTFE bomb.