Determination of trace amounts of carcinogenic substances: adsorptive stripping voltammetry of 1-[4′-(phenylazo)phenyl]-3,3-dimethyltriazene at a hanging mercury drop electrode

1-[4′-(Phenylazo)phenyl]-3,3-dimethyltriazene can be determined in the range from 1 × 10–5 to 2 × 10–7 mol dm–3 by direct current or differential-pulse voltammetry at a hanging mercury drop electrode. Direct current adsorptive stripping voltammetry can be used in the range from 2 × 10–8 to 10 × 10–8 mol dm–3 and differential-pulse adsorptive stripping voltammetry in the range from 1 × 10–8 to 2 × 10–11 mol dm–3. The extremely high sensitivity in the latter instance was achieved by using 200-fold diluted Britton–Robinson buffer as a base electrolyte together with a long accumulation time (up to 30 min at 1 × 10–11 mol dm–3). The relative standard deviation (seven determinations at 2 × 10–11 mol dm–3) was 8.6%.