サンセットエローのポーラログラムに対するゼラチンの影響

The initial part of the polarographic wave of Sunset Yellow (SY) is unusually deformed by gelatin in buffer solutions of pH values higher than 10, because the arrivalof SY to the surface of electrode is prevented by the electrostatic repulsion between the negative charge of the tri-basic anion formed by the dissociation of pro tons and that of gelatin adsorbed to the electrode surface. The phenomenon becomes more remarkable with the rise of pH because of the increase of tri-basic anions. As the electrode potential shifts to more negative, the wave height becomes larger and finally gets to the limiting value free from the effect of the gelatin adsorbed.