CADMIUM AND LEAD COMPLEXATION BY ANODIC-STRIPPING VOLTAMMETRY WITH A MERCURY MICROELECTRODE

Complexation reactions of lead by glutamic acid in KNO3 0.1 M and cadm ium by glycine at two ionic strengths (0.1 M KNO3 and 2 x 10(-3) M ber ate buffer) have been used to : 1) compare the stripping response in D CASV (direct current anodic stripping voltammetry) and DPASV (differen tial pulse anodic stripping voltammetry) at large (hanging mercury dro p electrode: HMDE) and small (thin film mercury microelectrode deposit ed on Pt/lr: mu ME) electrodes, 2) test classical DeFord-Hume's method with microelectrodes coupled to DCASV and DPASV, and 3) analyze the s uitability of both electrodes HMDE and mu ME coupled to anodic strippi ng voltammetry to measurements in freshwaters. Indeed due to the mass transport characteristics at microelectrodes, the fraction of a metal which contributes to the current may well be different From that at a conventional size electrode. The obtained results are in all the situa tions consistent among themselves and in good agreement with literatur e.