Construction of novel electrochemical sensors based on bimetallic nanoparticle functionalized graphene for determination of sunset yellow in soft drink

Three novel electrochemical sensors constructed by Pd-Pt bimetallic nanocages, Pt-Cu bimetallic nanoframes and Co-Ni bimetallic nanoflowers and poly (diallyldimethylammonium chloride) (PDDA)-dispersed graphene (Gr) were applied to determine sunset yellow (SY, E110). The PDDA-Gr-(Pd-Pt), PDDA-Gr-(Pt-Cu) and PDDA-Gr-(Co-Ni) nanocomposites formed different nanostructure with unique features and were characterized by transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The special morphology of the three bimetallic nanoparticles endows the designed electrochemical sensors with large active areas and good electrical conductivity, which provides more active sites for the target analyte and improves the sensitivity of the determination of sunset yellow. The developed sensors were investigated and compared with each other on the determination of SY by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimal experimental condition, the anodic peak currents of sunset yellow on three modified electrodes was linearly correlated with the concentration of sunset yellow in the ranges of 0.02–10.0, 0.02–10.0, 0.008–10.0 μM, respectively. The limits of detection (LOD) of SY were 6.0, 4.0 and 2.0 nM, respectively. In addition, the three new proposed sensors in this study were successfully applied to determine SY in real soft drink sample. This study provides a new platform for designing sensitive electrochemical sensor based on non-noble metals with low cost.