Electroreduction and pulse-polarographic determination of nicotinamide in multivitamin tablets.

The electroreduction of nicotinamide has been investigated by d.c., a.c. and pulse polarography, cyclic voltammetry and coulometry. A single well-defined polarographic wave is obtained from 2 M sulphuric acid and from 0.1 M sodium hydroxide. In both media, nicotinamide undergoes an irreversible 2-electron reduction; 3 hydrogen ions are consumed in acidic medium and two hydrogen ions in alkaline medium. The current is diffusion-controlled and proportional to the concentration in the range 0.6–120 μg ml−1. Reduction mechanisms are proposed. A simple and rapid method for the determination of nicotinamide in multivitamin tablets by differential pulse polarography is described.