Nickel voltammetric procedure

Analytical methods for detection of nickel in biological materials and water include various spectrometric, photometric, chromatographic, polarographic, and voltammetric procedures. Detection limits for the most sensitive procedures - depending on sample pretreatment, and extraction and enrichment procedures - were 0.7-1.0 ng/L in liquids, 0.01-0.2 ttg/m in air. 

Pihlar, B., Valenta, P. and Nurnberg, H.W. (1981). New high-performance analytical procedure for the voltammetric determination of nickel in routine analysis of waters, biological materials and food. Fresenius Z. Anal. Chem. 307, 327-346. 

Procedures suitable for the incorporation of chemical or biochemical substances or ion-exchange sites onto an electrode surface have been developed in various laboratories. " Such modified surfaces can then be used to perform a variety of functions. They have, for instance, been employed to preconcentrate analytes prior to voltammetric analysis and hence impove sensitivity. For example, dimethylglyoxime has been used to preconcentrate nickel and EDTA to preconcentrate silver." If this preconcentration can be achieved in an environment conducive to rapid electron transfer, then sensitivity will be enhanched even further. Alternatively electrocatalysts have been attached to electrode surfaces, and by speeding up what would otherwise be a sluggish electron transfer process, increased sensitivity has been attained. However, this approach yields no added selectivity and a large background must usually be tolerated. 

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