Electrosynthesis and electrochemical characteristics of 2,2′-(4,5-dihydroxy-3-methoxy-1,2-phenylene)bis(3-oxo-3-phenylpropanenitrile): application as a mediator for determination of hydroxylamine at a carbon nanotube modified electrode surface

Analytical Methods Pub Date: 2014-05-28 DOI: 10.1039/C4AY00731J

Abstract

Electrosynthesis and electrochemical characteristics of an electrodeposited 2,2′-(4,5-dihydroxy-3-methoxy-1,2-phenylene)bis(3-oxo-3-phenylpropanenitrile), DMPP, film on a multi-wall carbon nanotube modified glassy carbon electrode (DMPP-MWCNT-GCE) and its role as a mediator for electrocatalytic oxidation of hydroxylamine are described. Cyclic voltammograms of the DMPP-MWCNT-GCE indicate a pair of well-defined and quasireversible redox couples with surface confined characteristics in a wide pH range of 2.0–12.0. The charge transfer coefficient, α, and the charge transfer rate constant, ks, of DMPP-MWCNT were calculated to be 0.51 and 10.7 ± 1.7 s?1, respectively. The DMPP-MWCNT-GCE shows a dramatic increase in the peak current and a decrease in the overvoltage of hydroxylamine electrooxidation in comparison with that seen at a bare or MWCNT modified glassy carbon electrode. The kinetic parameters of electron transfer coefficient, α, heterogeneous electron transfer rate constant, k′, and exchange current density, j0, for the oxidation of hydroxylamine at the modified electrode surface were determined using cyclic voltammetry. Differential pulse voltammetry (DPV) exhibits two linear dynamic ranges 1.0–10.0 μmol L?1 and 10.0–300.0 μmol L?1 as well as a detection limit of 0.37 μmol L?1 for hydroxylamine determination. Finally, the modified electrode was successfully used for the determination of spiked hydroxylamine in a tap water sample.

Graphical abstract: Electrosynthesis and electrochemical characteristics of 2,2′-(4,5-dihydroxy-3-methoxy-1,2-phenylene)bis(3-oxo-3-phenylpropanenitrile): application as a mediator for determination of hydroxylamine at a carbon nanotube modified electrode surface
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