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 μl of 1+9 diluted sea-water were injected in a carrier stream of 0.028 mol l –1 HNO 3 . The detection limits were 0.7 μg l –1 Mn, 1.4 μg l –1 Mo and 0.10 μg l –1 U. ETV-ICP-MS was used for the determination of Cd and Pb. The analytes were vaporized as chlorides at 800 °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).