Collect. Czech. Chem. Commun. 1984, 49, 1635-1641

A contribution to the electrochemiluminiscence determination of cobalt with luminol

Jiří Herejk and Záviš Holzbecher

Department of Analytical Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6


The effect was studied of experimental conditions (pH, ionic strength, supply voltage, and type of electrodes) and of the presence of some cations and anions on the luminiscence of aqueous solutions of luminol generated by alternating current. Of the ions studied, Co2+ and Br- affected the electrochemiluminiscence (ECL) of luminol to the highest extent. Co2+ ions increase the ECL of luminol in alkaline solutions in concentrations cCo2+ = 10-3-6.10-6 mol l-1, the limit of determination of cobalt is 0.13 μg ml-1. In the presence of bromide in concentrations higher than 0.2 mol l-1, however, Co2+ lowers the ECL intensity over the concentration region of cCo2+ = 10-2-2.10-4 mol l-1. Alkali metal and alkaline earth cations as well as small amount of Pb2+, Zn2+, Cu2+, Cr3+, and Fe3+ have no appreciable effect on the ECL of luminol.