Polarographic Study of Molybdosilicic Acids (MSA) in Citrate Buffer

Abstract

Polarographic studies of molybdosilicic acid in a citrate buffer solution have been made. Phase-selective alternating current of 1st harmonic (AC 1_T) has been the technique of choice, although differential pulse (DP) and fast direct current (DC_T) have also been tried. A specific peak of each form of MSA, α and β has been observed and studied as a function of pH with AC 1_T. The kinetic study in the range of pH in which both forms of the acid are produced could therefore be possible. The time of formation of each species has been estimate at various pH values, as well as the influence of the molybdate concentration in the polarograms of α-MSA. The peaks of molybdate reduction as a function of pH have also been characterized.

Key Words:

• molybdosilicic acids
• alternating current polarography
• silica