DETERMINATION OF 7 TRACE-ELEMENTS IN ENVIRONMENTAL WATER SAMPLES BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY WITH ONLINE PRECONCENTRATION

An on-line preconcentration method was studied to allow the simultaneous determination of Mn, Co, Ni, Cu, Zn, Cd and Pb in 5 ml environmental water samples by inductively coupled plasma mass spectrometry. A semiautomated system with a microprocessor-controlled high performance quaternary gradient pump and valves was used to lead and transport the mobile phase. The system includes a column containing silica-immobilized 8-hydroxyquinoline. The pH of the samples was adjusted to 8 to improve the retention of several elements, in particular manganese. Quantitative elution from the column took 3.5 min with a 1.5 M HCl/0.6 M HNO3 mixture at a flow rate of 2.0 ml min-1. Mn and Co were determined by a standard additions technique, and stable isotope dilution was applied for Ni, Cu, Zn, Cd and Pb. The good precision and accuracy of this method are demonstrated by analyzing standard samples of riverine water (SLRS-2), estuarine water (SLEW-1) and coastal seawater (CASS-2). The detection limits of the method range from 7 ng l-1 for Cd to 130 ng l-1 for Zn.