POLAROGRAPHIC-BEHAVIOR AND DETERMINATION OF DICHROMATE IONS IN ABSENCE AND PRESENCE OF CADMIUM(II) ION IN THIEL BUFFER SOLUTIONS

The polarographic behaviour and determination of dichromate ions have been investigated in thiel buffer solutions of pH 2.75, 4.16, 5.22 and 7.2. The reduction of Cr2O72- ions takes place via single, or three w aves depending upon the pH value. Microcoulometric experiments have be en performed at the obtained limiting current region of the different waves at various pH values. The mechanism of the reduction occurring a t the D.M.E. has been deduced and interpreted. A method for analytical determination of Cr-VI on both the micro-and macro-scales is reported . Analysis of a binary mixture Cr-VI/Cd-II in thiel buffer solution at pH 2.75 is also investigated.