Polarographic and voltammetric determination of 1-(4-methoxyphenyl)-3-methyltriazene

The polarographic behaviour of 1-(4-methoxyphenyl)-3-methyltriazene in a mixed aqueous-methanolic medium was investigated by last 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. A mechanism has been proposed for its polarographic reduction and optimal conditions have been found for its determination by last polarography in the concentration range 2-100 μmol l^-1 and by differential pulse polarography at a dropping mercury electrode, differential pulse voltammetry at a hanging mercury drop electrode and linear scan voltammetry at a hanging mercury drop electrode in the concentration range 0.2-100 μmol l^-1. The sensitivity of the determination can be further improved through adsorptive accumulation of the test substance on the surface of the hanging mercury drop electrode; fifteen-second accumulation in stirred solution allows determination in the range 0.01-0.1 μmol l^-1.