A new electrochemical sensor for the simultaneous determination of guanine and adenine: using a NiAl-layered double hydroxide/graphene oxide-multi wall carbon nanotube modified glassy carbon electrode

An electrochemical sensor was developed for guanine (GA) and adenine (AD) detection using multiwall carbon nanotubes (MWCNTs) with the hybrid NiAl-layered double hydroxide/graphene oxide (NiAl-LDH/GO) on a glassy carbon electrode (GCE), referred to as MWCNTs/NiAl-LDH/GO/GCE. The modified electrode was used for the simultaneous detection of GA and AD. Electrochemical performances related to the direct electrooxidation of GA and AD at the modified electrode were investigated, showing that their peak currents were greatly enhanced due to the presence of MWCNTs/NiAl-LDH/GO nanohybrids. Also, it was revealed that the oxidation peak potentials of GA and AD on the modified electrode were negatively shifted, leading to the increase of their electrocatalytic activity at the surface of MWCNTs/NiAl-LDH/GO/GCE. The effects of different parameters such as pH, accumulation time, accumulation potential, and scan rate on the sensitivity were investigated too. Determination of purine bases was done by a linear sweep voltammetric (LSV) technique. The linear ranges of 0.010-45 mM, with the detection limit of 3 nM for GA, and 0.08-45 mu M, with the detection limit of 20 nM for AD, were achieved. Finally, the proposed electrochemical sensor was employed for the simultaneous determination of GA and AD in single-strand deoxyribonucleic acid (ssDNA) samples.