Polarography as an Analytical Tool

Abstract

Abstract Polarography is a useful analytical tool for determining many substances in solutions at small concentrations, and is frequently applied to analysis of minor constituents. Conventional polarography employs a dropping mercury electrode, can measure solutions in concentrations ranging from 10-2 to 10-5M, and requires only a few tenths of ml for analysis. Because of the difficulty of obtaining diffusion control in practice, methods are comparative and involve empirical calibrations with standard solutions. Practical tolerances have been worked out to insure that results are reliable to 2 relative per cent. Interferences have been lessened by several means, e.g., complexing, separation by electrolysis at controlled potential, selective extraction, and improvements in circuitry to permit use of relatively dilute supporting electrolytes. Modified polarographic methods include solid electrodes, derivative polarography, differential polarography, cathode ray polarography, anodic stripping polarography, and oscillographic polarography.