Cathodic stripping voltammetric determination of selenium(IV) at a nafion coated mercury film electrode modified with 3,3′-diaminobenzidine

Determination of selenium(lV) was investigated on a 3,3′-diaminobenzidine/Nafion/mercury film modified glassy carbon electrode (DNMFE). The 3,3′-diaminobenzidine/Nafion coating solution was irradiated by a tungsten light bulb to oxidize the 3,3′-diaminobenzidine. This coating solution was then spin-coated onto a glassy carbon electrode. Subsequently, mercury was electrodeposited onto the electrode surface. Selenium(IV) was preconcentrated onto the DNMFE from the sample solution saturated with ethylenediaminetetraacetate (EDTA) at an accumulation potential of -0.35 V, and determined by cathodic square-wave stripping voltammetry (SWSV). Various parameters affecting the selenium determination were examined. With 5 min accumulation, the analytical signal was linear from 1 to 300 μgL^-1, and the detection limit was 0.48 μgL^-1. The proposed procedure showed a good accumulation efficiency for selenium and good resistance to interferences from metal ions as well as surface-active compounds.