Promoting effect of iodide on the hexacyanomanganate(IV)—arsenic(III) redox reaction, for kinetic determination of iodide

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

“…Before use, the solution must be kept at about 0 °C for about 1 h to allow the Mn III disproportionation reaction to proceed to completion. 21 The Mn IV solution thus obtained can be used for a period of 6-8 h if kept at about 0 °C. Cysteine, tyrosine and tryptophan solutions, 1.04 3 10 22 mol l 21 .…”

“…The solutions were stored in a refrigerator. From these, working standard solutions ranging from 1.04 3 10 25 to 5.20 3 10 23 mol l 21 were prepared by dilution with 0.1 mol l 21…”

“…Hexacyanomanganate(iv) oxidizes these amino acids according to slow reactions. 12 Other amino acids give virtually no reaction with Mn(CN) 6 22 (only cystine and methionine give a very slow reaction when they are at concentrations higher than 10 23 mol l 21 ). Other oxidizing cyano complexes (Mo V , W V and Fe III ) only react with cysteine and hence, the Mn IV cyano complex (Fig.…”

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

“…We have been looking for some experimental proof of the existence of the postulated intermediates (steps [12]- [14]), but neither spectral (uv-visible) nor electrochemical (cyclic voltammetry) evidence has been found, probably because the steady-state concentrations lie under their detection limits. Nonetheless, the existence of the intermediates has been postulated to explain the pseudo-first-order kinetics found.…”

“…The manganese(1V) cyano complex formed decomposes to Mn(H20)6'+ and (CN)', but the reaction is auite slow at room temDerature (1 1) and thus ~, the M~( c N )~~-solution can be used for oxidizing purposes for a period of time (12). The kinetics of the decomposition reaction of M~( C N )~~-has already been studied and a mechanism has been proposed (1 1).…”