Polarographic and voltammetric determination of N,N-dimethyl-4-amino-4′-sulfoazobenzene

The polarographic behaviour of N,N-dimethyl-4-amino-4′-sulfoazobenzene was investigated by tast polarography and differential pulse polarography at a dropping mercury electrode, constant-potential coulometry at a large area mercury electrode and cyclic voltammetry at a hanging mercury drop electrode. Optimum conditions have been found for its determination by tast polarography in the concentration range of 2-100 μmol l^-1, differential pulse polarography at a dropping mercury electrode in the concentration range of 0.2-100 μmol l^-1 and by differential pulse voltammetry at a hanging mercury drop electrode in the concentration range of 0.02-10 μmol l^-1. The sensitivity of the determination can be further improved by adsorptive accumulation of the test substance on the hanging mercury drop electrode. Three-minute accumulation in stirred solution allows determination in the range of 0.2-100 nmol l^-1.