ベンゾトリアゾールのポーラログラフィーと銅イオンとの錯生成反応を利用する電流滴定

概要

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Polarographic behaviour of benzotriazol (I) in aqueous solution and its application to the determination of I were examined. I gives a cathodic wave on direct current (DC) polarogram in only strongly acidic solution. An increase in pH of the solution results in a marked decrease of the limiting current. The half-wave potentials are correlated with pH by a straight line with a slope (ΔE/ΔpH) of ca. -0.08. These findings support the electrode reaction mechanism including the four-electron reduction of the protonated species of I reported by Lund. In the positive potential region, I shows four anodic waves due to the complex formation between mercury and I. The pH dependence of these waves has been explained in relation to the acid-base equilibria of I. The limiting current of the cathodic wave obtained in 0.2_M HCl solution increases linearly with the increasing concentration of I ranging from 5.0×10^<-6> to 5.0×10^<-8>_M. This result is directly applicable to the simple determination of I. In a relatively higher pH region, I reacts with Cu^<2+> to produce a blue-green precipitate corresponding to the 1 : 2 complex of Cu^<2+> and I. The amperometric titration of I was examined using Cu^<2+> as a precipitant in acetate buffer solution (pH 5.6). This method can be used to determine the concentrations of I up to 5×10^<-4>_M, with a relative error within ±3.0%.
公益社団法人日本薬学会の論文
1976-04-25