Abstrakt
The aim of this contribution was to develop sensitive, inexpensive, and less time-consuming voltammetric methods for the determination of pyruvic acid based on its derivatization with o-phenylene-diamine, the resulting reaction product being determined by direct current voltammetry and differential pulse voltammetry at a mercury meniscus modified silver solid amalgam electrode. The optimization consisted of finding a suitable medium and regeneration of the electrode surface for the determination of 2-hydroxy-3-methyl-quinoxaline, a product of a derivatization reaction, and optimization of conditions for the derivatization reaction.
The optimal medium was a solution of the Britton-Robinson buffer of pH = 4.0 and the optimal regeneration potentials were E-in = -500 mV and E-fin = -900 mV for both techniques. Optimization of the derivatization reaction consisted of finding the optimal concentration of o-phenylenediamine (2.0 x 10(-3) mol L-1), pH of the reaction (1.2), reaction time (30 min), and reaction temperature (35 degrees C).