Simultaneous determination of guanine and adenine in DNA based on NiFe2O4 magnetic nanoparticles decorated MWCNTs as a novel electrochemical sensor using adsorptive stripping voltammetry

An electrochemical sensor was developed for guanine and adenine detection using multiwall carbon nanotubes (MWCNTs) decorated with NiFe2O4 magnetic nanoparticles on a glassy carbon electrode. Incorporation of MWCNT/NiFe2O4 nanohybrid on the surface of the electrode significantly increases oxidation the peaks currents but reduces the peaks potential of guanine and adenine. The modified electrode was employed for detecting purine bases using linear sweep voltammetry and hydrodynamic amperometry. With hydrodynamic amperometry, the peaks current of both guanine and adenine showed linear dependence on their concentrations in the range of 3.0-45.0 mu mol L-1 for guanine and 3.0-40.0 mu mol L-1 for adenine. When linear sweep voltammetry was used, the peak currents exhibited linear dependence on guanine in the concentration range of 0.05-3.0 mu mol L-1 and on adenine in the concentration range of 0.1-4.0 mu mol L-1. The limit of detection (S/N = 3) was found to be 0.006 and 0.01 mu mol L-1 for guanine and adenine, respectively. Linear sweep voltammetry was also used for simultaneous determination of adenine and guanine. Finally, the proposed electrochemical sensor was employed to determine guanine and adenine in single-strand deoxyribonucleic acid (ssDNA) samples with satisfactory results. (c) 2012 Elsevier B.V. All rights reserved.