Polarographic maxima revisited

Abstract

The relation between maxima (of the first kind) and drop lifetime-potential (TE) curves was investigated by recording both the DC polarogram and the T E curve and comparing the latter to that obtained with the blank solution, under identical conditions. The advanced instrumentation for measuring drop life-time allowed the detection of minute variations occurring in various regions of the applied potential range. Positive maxima were studicd with CU"lC104, Cu"/CI , Pb"/CI -, Fc"'!CZO: and UO:+ /C@-systems; negative maxima, with solutions of Ni", Zn" and Pb".Hypotheses explaining the variations in maximum shape and height and in drop lifetime, taking into account the nature of the electroactive species (mainly, the location of the reduction step vs. the pzc), or the supporting electrolyte concentration are submitted, including the differing behavior observed with positive and negative maxima.

The impact of high Zn° concentrations on the application of AGNES to determine free Zn(II) concentration

“…(i) The ''turbulence" hypothesis [22,[26][27][28][29]. Observation 4 requires some mechanism to produce currents larger than those yielded by diffusion limited conditions.…”

Increased sensitivity of anodic stripping voltammetry at the hanging mercury drop electrode by ultracathodic deposition

“…Oscillations in mercury electrodes are known in literature [23][24][25][26][27][28][29][30]. Usually they are related to similar phenomena to those observed in the maxima of first kind in classical polarography, which remarkably is mostly observed at cathodic polarizations [30][31][32]. A work of particular interest was published in 2006 by Islam et al [24], researchers were actually able to film and photo the circular movement of a HMDE while performing cyclic voltammetry over 2,1,3-benzothiadiazole.…”