Some data for the electroanalytical use of fundamental second and third harmonic alternating current polarography

Analytical applications of the various harmonics of alternating current polarography are more satisfactory the higher the degree of reversibility of the a.c. electrode process. At present very few reports on the development of a.c. polarographic methods of analysis attempt to assess the reversibility of the a.c. electrode process because most methods for doing this are rather complex and require the measurement of parameters that are of little interest to the analytical chemist. In d.c. polarography the Heyrovskyllkovic equation allows the ready assessment of reversibility and in analytical papers on d.c. polarography this equation is frequently used. With a.c. polarography, where it is even more important to establish the reversibility or otherwise of the a.c. electrode process, the establishment of easily used equations based on parameters of interest to analytical chemists seems desirable. This project has been undertaken in this work. Equations and data are given which allow the reversibility of fundamental, second and third harmonic a.c. electrode processes to be determined directly from the recorded polarogram. The equations and data are shown to be applicable to virtually all a.c. polarographic techniques and conditions. They apply to phase sensitive and non-phase sensitive a.c. polarography, a.c. voltammetry at hanging mercury drop and mercury pool electrodes, rapidly dropping and other varieties of a.c. methodology. Contrary to expectation, the equations apply to much larger amplitudes of a.c. potential than would be anticipated from the literature.