The effect of dissolved oxygen on A. C. polarograms of some metallic ions

In A. C. polarography the relationship between peak height and concentration of depolarizer is linear, provided that an acidic or buffer sub-stance is used as the different supporting electrolyte, even though oxygen is not expelled from the polarographic solution. For example, the following results were confirmed: (1) Ammonium salt is suitable for use as the different supporting electrolyte in the polarogram of Cd ion. (2) Potassium iodide and bromide are better than potassium chloride. (3) The calibration line has an entirely linear relationship in the ammonium nitrate solution of Cd, Pb, and Zn ions. (4) The reduction waves of Zn and In ions have higher peak height when potassium biphthalate is added than when not. Furthermore, the following interesting results were obtained concerning the very delicate and complicated electrode reaction occurring in A. C. bridge polarography: (1) A change in the reduction wave of Pb ion was observed during the expelling of oxygen by hydrogen. (2) A change in the reduction wave of Zn ion during the changing of pH was also noted.