A voltammetric study of the kinetics of the hexacyanomanganate(III) disproportionation in acidic medium

Abstract

GUILLERMO LOPEZ-CUETO and CARLOS UBIDE. Can. J. Chem. 69, 21 12 (1991). The fast disproportionation of hexacyanomanganate(II1) in acidic medium yields Mn(CN)6'--and Mn(H20)6". The reaction has been studied by amperometry, with a rotating platinum-disk electrode, at a 1.0 V (vs. SCE) constant potential, in the acidity range 0.01-2.0 M and at temperatures between -5 and 15°C. A reversible one-electron process takes place with a 0.85 V (vs. SCE) half-wave potential that is not dependent on acidity. The reaction kinetics is pseudo-first order in s-' M-' , respectively. A mechanism is proposed where the three terms of kobs are assigned to pathways involving hexacyanomanganate(II1) in three different states of protonation. From the effect of temperature the activation parameters, AH# and AS#, for each pathway are also reported.

Improved selectivity in multicomponent determinations through interference modelling by applying partial least squares regression to kinetic profiles

“…Data were acquired with a diode-array spectrophotometer and results in both cases are compared. Hexacyanomanganate(iv) has a relatively high redox potential (E 1/2 = 0.85 V versus SCE) 18 and has previously been used as an oxidizing agent for the individual kinetic determination of amino acids. 12 Finally, the use of PLSR, in order to overcome interferences at variable concentrations and without previous separation, was tested.…”

Individual Kinetic Determinations Using Partial Least Squares Calibration

“…In this paper, the oxidation of three amino acids (cysteine, tyrosine and tryptophan) by hexacyanomanganate(iv) in acidic medium is used to show how PLS can be applied, with good results, to individual kinetic determinations, even when the initial rate method gives poor results. Hexacyanomanganate(iv) has a relatively high redox potential of 0.85 V (versus SCE) 9 and has sometimes been used as an oxidant for analytical purposes. 10 All the results were compared with those obtained by applying the initial rate method to the same kinetic runs.…”