Determination of Total Mercury in Porewater of Lake Sediments: Control of Interference from Dissolved Organic Carbon and Sul- phide

A method based on cold vapor atomic fl uorescence spectrometry was developed to determine total dissolved Hg in lake sediment porewaters while considering the presence of dissolved forms of organic carbon and sulfide. Different parameters were tested including the preservation of samples, the acidity of the solution containing the analyte, the control of interference and the effi ciency of the cold and microwave digestion processes. BrCl appeared to be the treatment that can better manage all those parameters and lead to good quality results. The treatment of porewater samples with a 2% (v/v) BrCl proved to be effi cient for sample preservation and digestion and the acidic BrCl solution can remove effi ciently interference coming form dissolved forms of organic carbon and sulfi de.