Nitrogen-doped graphene-polyvinylpyrrolidone/gold nanoparticles modified electrode as a novel hydrazine sensor

Nitrogen-doped graphene (NG)-polyvinylpyrrolidone (PVP)/gold nanoparticles (AuNPs) modified screen printed carbon electrode (SPCE) was prepared for the square wave voltammetric (SWV) determination of hydrazine. For electrode modification, NG-PVP nanocomposites were fabricated on SPCE surface via electrospraying and then AuNPs were electrochemically deposited on top of NG-PVP nanocomposite layer. The factors affecting the sensor sensitivity, such as electrode composition and SWV parameters were optimized. Scanning electron microscopy, transmission electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy were used for physical and electrochemical characterization of modified electrodes. Due to the synergistic effect of NG-PVP and AuNPs, the modified SPCE showed a 10 time increase in anodic peak current compared with an unmodified SPCE, indicating the high sensitivity of the system. Moreover, this system exhibited an excellent electrocatalytic activity toward hydrazine oxidation. Under optimum conditions, a wide linear range of 2-300 mu M, a low detection limit of 0.07 mu M and a high sensitivity of 1.370 mu A M-1 cm(-2) were obtained for hydrazine. Interestingly, this system was highly selective against a high level of sugars (e.g. glucose, sucrose and lactose). To the best of our knowledge, this is the first report, in which NG-PVP/AuNPs modified SPCE was successfully developed and applied for the detection of hydrazine in high sugar fruit and vegetable samples. (C) 2016 Elsevier B.V. All rights reserved.