Abstract
The voltammetric signal of 5-nitroquinoline with reducible nitro and quinoline moieties largely depends on the pH of the indifferent electrolyte, electrode pretreatment, activation between individual scans, and boron concentration of the BDD film electrode. Anodic pretreatment at +2.4 V for 5 min in 0.5 mol dm(-3) H2SO4 and 20 s stirring between individual scans assured repeatable signals of nitro group in the whole pH range 2.0-12.0; in acetate buffer pH 5.0 limit of detection is 2 x 10(-7) mol dm(-3) for differential pulse voltammetry.
The reduction of quinoline skeleton is visible in the pH range of 6.0-11.0. Presence of oxygen in the measured solutions led to slight increase of peak heights and acceptable increase of its relative standard deviation.
BDD films with metallic type of conductivity deposited at B/C ratio 2000-8000 ppm exhibit faster electron transfer at lower potential for nitro group reduction than semiconductive films 500 and 1000 ppm. [GRAPHICS] .