Fabrication of nano structured copper phosphate electrodes for the detection of α-amino acids

Cu-3(PO4)(2)-deposited electrodes capable of detecting nonelectroactive alpha-amino acids (AAs) are developed by the dissolution-precipitation method. The Cu-3(PO4)(2)-dominated compounds of flake-shaped nanostructures are quickly and uniformly deposited on the surface of acicula-nanostructured Cu(OH)(2)-electrodeposited electrodes in a 100mM Na2HPO4 solution (pH 5.0) within 2h. Analysis of X-ray photoelectron spectroscopy and electrochemical kinetics shows that an oxidative reaction at +0.11 V increases the ratio of H2PO4- on the electrode surface and produces the Cu-II(H2PO4)(2) complex. Moreover, the Cu-II compounds and the AAs can form complexes to accompany the chemical oxidation of AAs and the formation of the Cu-I complex, increasing the amount of oxidative current detected via the chemical-electrochemical mechanism. The amperometric response presented good linearity and sensitivity in the range of 143-600 mu M for electroactive and nonelectroactive alpha-AAs. The Cu-3(PO4)(2)-deposited electrodes are integrated into a chromatographic separation systems as an AA sensor to have promise for the detection of biological and food samples. (C) 2014 Elsevier B.V. All rights reserved.