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|Type:||Artigo de periódico|
|Title:||An amperometric sensor for L-cysteine based on nanostructured platform modified with 5,5 '-dithiobis-2-nitrobenzoic acid (DTNB)|
|Abstract:||In this work, the activation of 5,5'-dithiobis-2-nitrobenzoic acid (DTNB) in situ is proposed, for L-cysteine electrooxidation at low overpotentials. The redox mediator was immobilized in an nanostructured platform containing multi-walled carbon nanotubes (MWCNTs), polyethylenimine (PEI) and gold nanoparticles (GNPs). The optimization of the interface was performed monitoring the R-NO/R-NHOH redox couple in which was electrogenerated in situ by cycling the potential between 0.1 and -0.7 V versus SCE at 100 mV s(-1) The kinetic parameters such as the apparent electron transfer rate constant (k(s)) and the rate constant of the reaction between L-cysteine and DTNB (k(obs)) were evaluated. The electrocatalytic oxidation oft-cysteine was studied by means of cyclic voltammetry, chronoamperometry and amperometry. The sensor presented a linear response range for CyS from 9.0 up to 250 mu molL(-1) with sensitivity of 21 nA mu mol(-1), detection and quantification limits of 2.7 and 9.1 mu mol L(-1) respectively, with a response time of 0.12 s at an applied potential of 0 mV versus SCE. (c) 2010 Elsevier By. All rights reserved.|
|Editor:||Elsevier Science Sa|
|Appears in Collections:||Artigos e Materiais de Revistas Científicas - Unicamp|
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