Thick-film graphite electrodes in stripping voltammetry

Abstract

Various types of modified thick-film graphite electrodes are reviewed. Two modification options are available: either in situ modified or beforehand. Electrodes modified in situ by various organic compounds were used for the determination of W, Mo, Cr, Ni and Mn by adsorptive stripping voltammetry. Insoluble inorganic salts, insoluble organic complexes or soluble compounds protected with Nafion were used for modification of the electrode surface beforehand. These pre-conditioned electrodes permit quantification of Pb, Cd, Cu, Zn, Sn, As and Hg ions. The detection limits of these elements were in the sub-μg/L range. The relative standard deviation did not exceed 10–15%. Measurements were made without deaeration of test solutions and normally without destroying small organic matter found in surface waters. A number of characteristics, such as the formation of well-shaped peaks and stable increments of peaks after standard additions, as well as elimination of the mechanical surface regeneration stage and metallic mercury or its soluble salts from the analytical procedure and a long shelf-life of the electrodes make them promising for electroanalysis and for application in portable field instruments.