A novel ZnO/reduced graphene oxide and Prussian blue modified carbon paste electrode for the sensitive determination of Rutin

A carbon paste modified sensor based on a novel composite of zinc oxide nanoparticles deposited on reduced graphene oxide（ZnO-rGrO） and Prussian blue（PB） was drop-cast（ZnO-rGrO-PB/MCPE） for the sensitive estimation of Rutin（Rtn） at pH 7.0.The high surface area of ZnO-rGrO and electrocatalytic property of PB promotes the oxidation of Rtn. Field emission scanning electron microscope（FE-SEM） and energy-dispersive X-ray spectroscopy（EDX） techniques were employed to confirm the deposition of ZnO-rGrO and PB on carbon paste electrode（CPE）. The ability of ZnO-rGrO-PB/MCPE in charge transfer at the interface was investigated using electrochemical impedance spectroscopy（EIS）. The heterogeneous rate constant（ks） and the charge transfer coefficient（α） have been calculated as 6.08 s-1 and 0.74 respectively. This sensor showed a wide linear response for Rtn from 7.0×10-8to 7.0×10-6 M and 7.0×10-6 to 1.0×10-4 M with a limit of detection（2.05±0.04）×10-8 M（S/N=3）. The application of ZnO-rGrO-PB/MCPE was found in the analysis of Rtn in fruit juice samples using standard addition method. This sensor showed good reproducibility, stability, selectivity and sensitivity.