Screen-printed electrodes (SPEs) modified with Variamine blue (VB), covalently attached to the oxidized single-walled carbon nanotubes (SWCNTs-COOH), were developed and used as chemical sensors for the detection of the reduced nicotinamide adenine dinucleotide (NADH). The Variamine blue redox mediator was covalently linked to the SWCNTs-COOH by the N,N′-dicyclohexylcarbodiimide (DCC) and N-hydroxysuccinimide (NHS) chemistry. Infrared Fourier transform (FT-IR) spectroscopy revealed the presence of the amide bands situated at 1623 cm-1 (I band), 1577 cm-1 (II band) and 1437 cm-1 (III band) demonstrating the covalent linkage of Variamine blue to SWCNTs-COOH. The heterogeneous electron transfer rate, kobs., was 13,850 M-1 s-1, and the ks and α were 0.8 s-1 and 0.56, respectively. The pH dependence was also investigated. SPEs modified with Variamine blue by using the DCC/NHS conjugation method, showed a variation of -36 mV per pH unit. A successful application was the development of a lactate biosensor obtained by the immobilization of the l-lactate dehydrogenase on the NADH sensor. © 2007 Elsevier Ltd. All rights reserved.
Detection of NADH via electrocatalytic oxidation at single-walled carbon nanotubes modified with Variamine blue / A., Radoi; D., Compagnone; M. A., Valcarcel; P., Placidi; Materazzi, Stefano; D., Moscone; G., Palleschi. - In: ELECTROCHIMICA ACTA. - ISSN 0013-4686. - 53:5(2008), pp. 2161-2169. [10.1016/j.electacta.2007.09.031]
Detection of NADH via electrocatalytic oxidation at single-walled carbon nanotubes modified with Variamine blue
MATERAZZI, Stefano;
2008
Abstract
Screen-printed electrodes (SPEs) modified with Variamine blue (VB), covalently attached to the oxidized single-walled carbon nanotubes (SWCNTs-COOH), were developed and used as chemical sensors for the detection of the reduced nicotinamide adenine dinucleotide (NADH). The Variamine blue redox mediator was covalently linked to the SWCNTs-COOH by the N,N′-dicyclohexylcarbodiimide (DCC) and N-hydroxysuccinimide (NHS) chemistry. Infrared Fourier transform (FT-IR) spectroscopy revealed the presence of the amide bands situated at 1623 cm-1 (I band), 1577 cm-1 (II band) and 1437 cm-1 (III band) demonstrating the covalent linkage of Variamine blue to SWCNTs-COOH. The heterogeneous electron transfer rate, kobs., was 13,850 M-1 s-1, and the ks and α were 0.8 s-1 and 0.56, respectively. The pH dependence was also investigated. SPEs modified with Variamine blue by using the DCC/NHS conjugation method, showed a variation of -36 mV per pH unit. A successful application was the development of a lactate biosensor obtained by the immobilization of the l-lactate dehydrogenase on the NADH sensor. © 2007 Elsevier Ltd. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
