Chemical accumulation and voltammetric determination of traces of nickel(II) at glassy carbon electrodes modified with dimethyl glyoxime containing polymer coatings

Abstract

The objective of the present study was to develop a solid mercury free electrode for the voltammetric determination of traces of nickel(II) in solution. For this purpose chemically modified electrodes (CME’s) were constructed from glassy carbon coated with dimethylglyoxime-containing polymers. CME’s based on a composite matrix, which contained polyvinyl chloride, polyaniline, and dimethylglyoxime were shown to possess the ability to accumulate traces of nickel(II) from ammonia buffered aquatic solutions by a purely chemical attachment. Moreover the nickel(II) contents of such solutions could be determined using voltammetric quantitation of the nickel(II) dimethylglyoximate deposits on the CME surfaces and the standard addition technique. The CME surfaces could subsequently be regenerated by acid treatment. The limit of detection for Ni(II) following a 240 s chemical deposition was estimated as 18 μg Ni l −1, and the CME results for traces of Ni(II) in fresh water compared well with the results obtained by atomic absorption spectroscopy. Moreover the CME’s retained their sensitivity for more than two days, i.e. significantly longer than the 3 h, during which analogous carbon paste electrodes completely lost their affinity to nickel(II).