▎ 摘　　要

The present work describes development of a simple and selective voltammetric sensor for the simultaneous determination of three DNA bases guanine (Gua), adenine (Ade) and thymine (Thy). The proposed poly(L-arginine)-electrochemically reduced graphene oxide modified glassy carbon electrode [p(L-arg)-ERGO/GCE)] exhibited well-resolved and well-defined peaks for the electro-oxidation of these DNA bases with an enhancement in peak current and reduction in peak potential, compared to bare electrode. The electro-catalytic efficiency might be due to the synergistic electro-catalytic effect of L-arginine and reduced graphene oxide. For simultaneous determination, the peak currents of Gua, Ade and Thy showed linear variations in the concentration range 1.00 x 10(-4) - 3.00 x 10(-6) M, 1.00 x 10(-4) - 3.00 x 10(-6) M and 1.00 x 10(-4) - 1.00 x 10(-5) M, respectively. Mechanistic aspects of the electro-oxidation of Gua, Ade and Thy on the surface of p(L-arg)-ERGO/GCE have been explored. The proposed sensor also displayed good selectivity toward Gua, Ade and Thy without any considerable interferences from coexisting species. The applicability of the proposed sensor was demonstrated by simultaneously determining the concentration of Gua, Ade and Thy in the spiked urine and blood serum samples with satisfactory results.