Determination of nickel using electrochemical reduction and carbonyl generation with in situ trapping electrothermal atomic absorption spectrometry

A method is described for the determination of nickel at sub-ng g(-1) concentration levels. Electrochemical reduction of nickel in a flow-through electrolytic cell is followed by the generation and transfer of volatile Ni(CO)(4) to a graphite furnace where it is decomposed and trapped. Nickel is atomised and determined by atomic absorption spectrometry. The system has an overall efficiency of about 70% and gives a detection limit of 87 ng l(-1), based on a 1.0 ml sample volume. Limitations of the method are described; changes of the working electrode surface are shown to have a major influence on the reliability and sensitivity of the method. A method based on the chemical reduction of nickel using NaBH4 was used for comparison. The methods were validated by the determination of nickel in a water reference material.