Electrochemical fabrication of polyproline modified graphite electrode decorated with Pd–Au bimetallic nanoparticles: Application for determination of carminic acid

•Pd–Au bimetallic nanoparticles loaded on Poly(Pr)/GE were prepared by electrodeposition.•The modified electrode was successfully applied for carminic acid detection.•The developed electrode will be particularly useful for electrochemical biosensor studies.

A novel modified electrode has been developed, by electrodeposition of Pd–Au bimetallic nanoparticles (Pd–AuNps) on a polypyroline coated (Poly(Pr)) graphite electrode (GE). The structure and morphologies of Pd–AuNps/Poly(Pr)/GE were characterized by cyclic voltammetry (CV), square wave voltammetry (SWV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray photon spectroscopy (XPS) techniques. The electrocatalytic activities and morphologies of the new electrode were compared with individual monometallic AuNps/Poly(Pr)/GE and PdNps/Poly(Pr)/GE. This new bimetallic nanoparticle modified electrode (Pd–AuNps/Poly(Pr)/GE) was evaluated for determination of carminic acid. The oxidation peak (0.750 V) of carminic acid was found to be linearly related to carminic acid concentration in the range of 1.0 × 10− 8 to 1.0 × 10− 6 M with a detection limit of 5.90 × 10− 9 M. The proposed method was simple, less time consuming and showed a high sensitivity.