Principles and Applications of A-C and D-C Rapid Polarography with Short Controlled Drop Times

The techniques of a-c and d-c rapid polarography employing short controlled drop times and fast scan rates of potential are discussed in detail. Particular emphasis is given to comparing the methods with conventional polarography in electroanalytical applications. The shapes and main characteristics of both a-c and d-c polarograms are essentially the same as in conventional polarography. Any differences encountered generally arise from the different time scales of the two techniques. Reversible, quasi-reversible, and irreversible electrode processes are considered. In analytical applications, the rapid methods are superior to conventional polarography because of the considerable time saving gained from the fast scan rates of potential. The reproducibility is also marginally better. In fundamental studies, such as in the characterization of electrode processes, rapid polarography is also shown to be particularly useful. The analogy of behavior akin to a streaming mercury electrode is considered, as are other phenomena and characteristics introduced by having short controlled drop times. It is concluded that the technique could be given wider usage than presently accorded.