Fabrication of an electrochemical sensor based on graphene nanoplatelets modified platinum electrode for study the molecular interaction between sunset yellow and DNA

Graphene nanoplatelets (GNPs) are the stack of graphene sheets with an overall thickness of about 5 to 25 nm. They have platelet morphology with a diameter ranging from 0.5 to 25 μm,resulting in high aspect ratios up to the thousands. Their thermal, conductivity and mechanical properties are similar to carbon nanotubes (CNTs) but their aspect ratios are higher than CNTs. GNPs have been thus widely applied as the electrode materials in many fields [1–3], e.g. forsensing applications, loading catalysts and constructing batteries and supercapacitors. In this study, a platinum electrode was modified by graphene nanoplatelets using drop casting method for sensitive electrochemical oxidation/reduction of sunset yellow (SY) as a foodcoloring. The cyclic voltammetry study of SY on the surface of modified electrode showed a pair of well peaks at 0.708 and 0.625 V ( versus Ag/AgCl ) in phosphate buffer at pH = 7.4. Theredox peak currents of SY decreased gradually upon titration with calf thymus DNA and the anodic peak potential shifted to negative direction due to the formation of more stable adduct between SY and DNA in oxidized form. Moreover, the mode of SY–DNA interaction wasestimated from the variation in formal potential. In general the negative shift (anodic shift) in formal potential was caused by the electrostatic interaction of the small molecules with DNA [4].

Keywords:

Graphene nanoplatelets , Electrochemical sensor , Sunset Yellow , DNA , Interaction