The coulometric titration of the derivatives of N,N-dimethyl-4-aminoazobenzene by generated trivalent titanium

Abstract

Conditions for the coulometric generation of titanium(III) ions in buffer medium in the presence of sodium citrate were found on the basis of a study of the electrochemical behaviour of the Ti(III)/Ti(IV) system. A current efficiency of 100% was attained in acetic acid solution (c = 1 mol l-1) containing citric acid (c = 0.2 mol l-1) and titanium (IV) chloride (c = 0.1 mol l-1), with pH adjusted to 6 using sodium hydroxide, in the current density range 0.5 to 10 mA/cm2 using a mercury electrode and 1 to 2 mA/ cm2 using a paraffin-impregnated spectrographic carbon electrode. It was found that methanol does not affect the current efficiency at contents of up to 33% (v/v) and conditions were found for the coulometric titration of small amounts (0.2-2 mg) of some genotoxic derivatives of N,N-dimethyl-4-aminoazobenzene.