The remarkable detection power of inductively coupled plasma mass spectrometry (ICP-MS) was demonstrated by the analysis of an open ocean sea water reference material (with the acronym NASS-2). A 50-fold pre-concentration of several trace metals in the sea water was realised by their adsorption on to silica-immobilised 8-hydroxyquinoline, which separates the elements of interest from the bulk of the alkali and alkaline earth elements. The isotope dilution technique was used for the determination of seven elements (Ni, Cu, Zn, Mo, Cd, Pb and U). Accurate results were obtained for all of these elements except for Mo, with concentrations ranging between 0.027 and 11.5 µg l–1.