| Résumé | A new and sensitive method is described for the on-line determination and preconcentration of ultra-trace nickel using the coupling of a flow injection system with graphite furnace atomic absorption spectrometry. The method is based on photochemical generation of Ni(CO)4 and its trapping on the surface of a graphite furnace, the latter accomplished with approximately 35% efficiency by exposing a solution of Ni(II), containing formic acid, to UV irradiation. Optimum conditions for generation and trapping, as well as interferences from concomitant elemental ions, were investigated. A characteristic mass of 10 pg and LOD of 8 pg mL−¹ were obtained based on a 2 ml sample volume. The LOD can be further enhanced by increasing sample volume and reaction temperature, or by addition of copper ions. The precision was better than 3% (RSD) at 1 ng mL−¹. Environmental Certified Reference Materials were analyzed to validate the accuracy of the proposed method, including SLRS-4 (river water), MESS-3 (marine sediment), TORT-2 (lobster hepatopancreas) and DOLT-3 (fish liver tissue). |
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