Direct determination of trace metals in sea-water by inductively coupled plasma mass spectrometry

The direct determination of trace metals in sea-water by inductively coupled plasma mass spectrometry (ICP-MS) is described, based on sample introduction by flow injection analysis (FIA) and electrothermal vaporization (ETV). FIA-ICP-MS was used for the determination of Mn, Mo and U; 500 mu l of 1 + 9 diluted sea-water were injected in a carrier stream of 0.028 mol l(-1) HNO3. The detection limits were 0.7 mu g l(-1) Mn, 1.4 mu g l(-1) Mo and 0.10 mu g l(-1) U. ETV-ICP-MS was used for the determination of Cd and Pb. The analytes were vaporized as chlorides at 800 degrees C, without interference from the matrix elements. The detection limits were 4.1 ng l(-1) for Cd and 0.8 ng l(-1) Pb. The FIA-ICP-MS and ETV-ICP-MS results were validated by analysing a reference sea-water sample (NASS4).