Stripping chronopotentiometry at scanned deposition potential (SSCP). Part 4. The kinetic current regime

Metal speciation dynamics in colloidal ligand dispersions. Part 3: Lability features of steady-state systems

“…Even more relevant here is that for the complete depletion mode of scanned stripping chronopotentiometry (SSCP) [10] a known rigorous equation is available for the full wave in the kinetic current regime [11]. Using this expression we demonstrated that the characteristic parameters of the SSCP wave (the limiting wave height, s * , and the half-wave deposition potential, DE d,1/2 ) provide an indicator of changes in lability of metal complex systems [12].…”

Determination of Zn2+ concentration with AGNES using different strategies to reduce the deposition time

“…However, it is well-known [21][22][23][24][25][26][27][28][29] that the dissociation of complexes along the diffusion layer can play a very relevant role in the transport of the metal ions towards the electrode. Thus, in the successive metal-to-ligand ratios of a titration, the contribution of the complexes to the flux of metal towards the electrode reduces the required time practically to reach the target [30], especially if most of the metal is present as non-inert complexes. This effect can be deduced from the observation of the currents during the first stage in Fig.…”

Scanned stripping chronopotentiometry of metal complexes: lability diagnosis and stability computation

“…To evaluate the effect of ML on the reduction of M to M 0 at the electrode, we use the well-known concept of a reaction layer, with thickness, l ¼ ðD M =k 0 a Þ 1=2 , representing the distance that a free M can travel during its mean lifetime, 1=k 0 a [21]. A general expression for the steady-state SSCP curve for dynamic complexes influenced by homogeneous kinetics (with D ML ¼ D M ) was deduced in [18] on the basis of the Kouteck y-Koryta approximation. The generalization of this expression to include any D ML =D M ratio is straightforward.…”

“…When the stripping current is sufficiently low, the accumulated metal is completely depleted from the electrode and simple application of Faraday's law yields a direct quantitative relationship between the analytical signal (the stripping or transition time, s) and the pertinent species concentration in the sample. The relatively simple mathematical framework of SSCP [15], together with the far-reaching validity of the Kouteck y-Koryta approximation (spatial division of the diffusion layer into a non-labile and a labile region, separated by the boundary of the reaction layer [16,17]) allowed a rigorous expression to be obtained for the full SSCP wave in the kinetic current regime [18].…”