Sensor amperométrico a base de nanotubos de carbono e ácido Ferúlico para a detecção eletrocatalítica de NADH

Abstract

In this paper, we describe the development of a simple and efficient nanostructured platform based in multi-walled carbon nanotube (MWCNT) functionalized with ferulic acid (FA) in order to develop an analytical sensor for NADH.The poly-AF was electrogenerated in situ on the MWCNT deposited on glassy carbon, generating the coupleredox quinone / hydroquinone, E° = 0.244 vs. Ag / AgCl.The techniques used for this study were cyclic voltammetry and chronoamperometry, which were used to study the electrochemical behavior of modified electrode, kinetic parameters and analytical characterization of the platform.The chronoamperometric studies were also performed in order to obtain more information about the processes of oxidation of NADH and functionalized platform.Thus, using graphs and equations of Cottrell was possible to obtain values for the apparent diffusion coefficient (NADH) and constant catalytic reaction cat to NADH.The values of DNADH and cat determined were 4.49x10-6cm2s-1, 5.57x103 mol-1s-1L, respectively.The increase in reaction rate for NADH was attributed to efficient electron transfer between the species responsible for the redox couple (quinone / hydroquinone), electrogenerated in situ.The amperometric sensor in relation to NADH showed a linear range covering the range 1.0 to 20.3 mol L-1), limit of detection (0.0927 molL-1), limit of quantification (0.309mol L-1), sensitivity (0,29 A L mol-1), detection potential (+0.200 V vs. Ag / AgCl), response time of detection of 0.2s.From the performance achieved, the platform on nano structured MWCNT fundamentada da AF and justifies the use of this system as a new candidate for a redox mediator, becoming it an excellent ambient for the configuration of new biosensors that employ enzymes NADH dependent.