<Original Papers>Determination of Micro-Amounts of Metal Ions by Radiofrequency Polarography

The peak potentials, the relationships of wave heights to concentration and sensitivities for several metal ions in various supporting electrolyte solutions were investigated by radiofrequency polarography. Generally, in high sensitive measurements, straight calibration curves through the origin were obtained, but sometimes compensations for blanks were needed as in the measurement of indium. In HCl solution, straight calibration curves were obtained for In^, Cd^, Pb^, Cu^, Sn^, As^, and Sb^, and also in other supporting electrolyte solutions, H_2SO_4,H_3PO_4,HBr, and KCl, calibration curves were straight and through the origin. Sensitivities were as follows : in 2 M HCl, Bi^, 0.3μg/ml. cm ; Sb^, 0.05μg/ml. cm ; Cu^, 0.03μg/ml. cm ; As^, 0.1μg/ml. cm ; Pb^, 0.025μg/ml. cm ; Sn^, 0.1μg/ml. cm ; In^, 0.01μg/ml. cm ; Cd^, 0.01μg/ml. cm : in 0.5 M H_2SO_4,Cu^, 0.02μg/ml. cm ; Cd^, 0.02μg/ml. cm : in 1 M H_3PO_4,Cu^, 0.1μg/ml. cm ; Pb^, 0.15μg/ml. cm ; Cd^, 0.05μg/ml. cm : in 1 M HBr, Sn^, 0.4μg/ml. cm ; Pb^, 0.1μg/ml. cm ; Cd^, 0.1μg/ml. cm : in 1 M KCl, Cu^, 0.04μg/ml. cm ; Cd^, 0.03μg/ml. cm ; In^, 0.05μg/ml. cm ; Zn^, 0.06μg/ml. cm