Collect. Czech. Chem. Commun. 1994, 59, 2397-2414

Polarographic Determination of 4'-Substituted Derivatives of 3-Carboxy-4-hydroxy-6-acetylaminoazobenzene

Jiří Bareka, Piero Savarinob, Lucie Stuchlíkováa and Jiří Zimaa

a UNESCO Laboratory of Environmental Electrochemistry, Department of Analytical Chemistry, Charles University, 128 40 Prague 2, Czech Republic
b Instituto di Chimica Industriale, Università di Torino, Corso Massino D'Azeglio 48, 10125 Torino, Italy


Tast polarography, differential pulse polarography and cyclic voltammetry were applied to the examination of 7 derivatives of 3-carboxy-4-hydroxy-6-acetylaminoazobenzene with H, CH3, OCH3, Cl, COCH3, NO2 and NHCOCH3 substituents in position 4'. A general reduction mechanism was suggested for the substances. The half-wave potentials obtained from tast polarographic measurements were correlated with the Hammett σ constants of the substituents in the para-position. The plot of this dependence is linear, which suggests that the reduction mechanism is identical within the entire series. The optimum conditions for quantitation of the substances were found within the concentration regions of 1 .10-4 to 1 .10-6 mol l-1 for tast polarography and 1 .10-4 to 1 .10-7 mol l-1 for differential pulse polarography.