Theoretical and Experimental Evaluation of Multielement Analysis by Fundamental Harmonic Alternating Current Polarography

A method is given for the quantitative calculation of concentration ratios allowable in fundamental harmonic alternating current polarography for the direct simultaneous determination of two reversibly reduced species with similar summit potentials. The particular examples given are for two waves whose summit potentials differ by 100, 150, 200, and 300 mV and for a precision of 1%. Concentration ratios of 1:100 to 100:1 are considered as characteristic of those likely to be encountered in routine analysis. Such ratios are allowable generally when the separation in summit potential is 300 mV or greater. However, for separations less than this, the possibility of simultaneous determination depends on the number of electrons involved in the charge transfer of both species as is described. Excellent agreement between theory and experiment has been found, and the calculation method is considered to provide a reliable means for quantitatively computing the usefulness of the ac polaro-graphic method for the determination of a particular species in the presence of another for any given concentration ratio for the simultaneous determination of both species.