Transduction of interaction between trace tryptophan and surface-confined chromium salen using impedance spectroscopy. A  sensing device that works based on highly selective inhibition of mediator's Faradaic process.

Transduction of interaction between trace tryptophan and surface-confined chromium salen using impedance spectroscopy. A sensing device that works based on highly selective inhibition of mediator's Faradaic process.
Anal Chim Acta. 2018 Nov 07;1030:70-76
Authors: Shamsipur M, Taherpour AA, Sharghi H, Pashabadi A
Abstract
It is known that tryptophan (Trp) tends to be electropolymerized over a potential window that is mostly applied for voltammetric determination of Trp. Furthermore, over the applied potential range, most of Trp-sensors suffer from some possible interferences. Knowing these challenges motivated us to establish a novel sensing device able to monitor Trp before approaching the mentioned potential range, decreasing memory-effects and some sources of non-linearity during electrochemical measurements. However, considering its molecular structure, it is unrealistic to expect tryptophan oxidation in negative potentials. This work reports the application of a surface-confined chromium-salen complex that delivered a redox couple attributed to Cr(II)/Cr(III) at a low positive potentials. The recorded cyclic voltammograms (CVs) clarified that Trp has a high inhibitory activity toward the chromium oxidation peak in the alkaline medium at a low potential of -0.18 V vs. Ag/AgCl. The positive shift of the anodic peak potential of redox reaction disclosed that Trp drastically influenced the capability of the interfacial charge tra...

Source: Analytica Chimica Acta - July 25, 2018 Category: Chemistry Authors: Shamsipur M, Taherpour AA, Sharghi H, Pashabadi A Tags: Anal Chim Acta Source Type: research