Electrochemical sensor for amino acids and glucose based on glassy carbon electrodes modified with multi-walled carbon nanotubes and copper microparticles dispersed in polyethylenimine.

FABIANA A. GUTIERREZ; MARÍA D. RUBIANES ; GUSTAVO RIVAS

JOURNAL OF ELECTROANALYTICAL CHEMISTRY

ELSEVIER

Lugar: Amsterdam; Año: 2016 vol. 765 p. 16 - 21

0022-0728

This work reports the analytical performance of glassy carbon electrodes (GCE) modified with multi-walledcarbon nanotubes (CNT) and copper microparticles dispersed in polyethylenimine (PEI) (GCE/CNT-PEI-Cu) forthe quantification of amino acids, albumin and glucose. The best analytical performance was obtained withCNT-PEI-Cu prepared by sonicating for 15.0 min a mixture of 1.0 mg mL−1PEI, 1.0 mg mL−1CNT and3.0mgmL−1coppermicroparticles. In the case of amino acids and albumin, the analytical signalswere obtainedfrom the increase of the copper oxidation signal produced as a consequence of the complex formation betweenCu(II) and the amino acids. The sensor allowed the highly sensitive (submicromolar levels) and reproducible(3.9%) amperometric quantification of histidine, serine and cysteine at very low potentials (0.000 V) andpH 7.40. Albumin was quantified by Square Wave Voltammetry after 10.0 min interaction at −0.100 V withdetection limits of 1.2 mg mL−1.GCE/CNT-PEI-Cu was also used for the quantification of glucose by amperometry at 0.700 V in a 0.100Msodiumhydroxide solution through the known catalytic activity of copper towards the oxidation of glucose, with highlycompetitive detection limits (182 nM). GCE/CNT-PEI-Cu was successfully used for the quantification of aminoacids and albumin in pharmaceutical products and carbohydrates in beverages.