Flow injection determination of mercury with preconcentration by amalgamation on a gold-platinum gauze by inductively coupled plasma mass spectrometry

Trace concentrations of mercury in water samples mere determined by a method involving a preconcentration procedure and inductively coupled plasma mass spectrometry (ICP-MS) detection. Mercury vapour, generated by tin(II) chloride as the reductant, was trapped by amalgamation on a gold-platinum gauze, released by controlled heating and detected by ICP-MS. A how injection sample introduction system with time-based injection was used and the sensitivity was found to be proportional to the mass of mercury introduced. Quantitative recoveries of mercury from open ocean sea-water, coastal sea-water and fresh water reference materials were obtained. A detection limit of 200 pg l(-1) for a 25 ml sample was obtained. The precision of the method was 1% (relative standard deviation) at 1 mu g l(-1).