Design and synthesis of polypyrrole conductive ink based on sulfated chitosan for bactericide carbendazim detection.

ABSTRACT

Conductive polymers (CPs) are typically insoluble in solvents, and devising biocompatible hydrophilic CPs is challenging and imperative to expand the applications of CPs. Herein, sulfated chitosan (SCS) is used as a green dopant instead of toxic poly(styrene sulfonate) (PSS), and SCSpolypyrrole (SCSPPy) conductive ink is prepared by in situ polymerization. Due to the complex structure between PPy and SCS polyanion, the synthesized SCSPPy dispersion forms a well-connected electric pathway and confers superior conductivity, dispersion stability, good film-forming ability, and high electrical stability. As proof of our concept, electrochemical sensing utilizing an SCSPPy-modified screen-printed carbon electrode (SPCE) was performed towards carbendazim (CBZ). The SCSPPy on the SPCE surface displayed greater sensitivity to CBZ because the conductive complex structure eased the electrocatalytic action of SCSPPy by dramatically increasing the current intensity of CBZ oxidation and notably ameliorating stability. The sensor unveils the lowest detection value of 1.02 nM with a linear range of 0.05 to 906 µM for sensing trace CBZ by utilizing the pulse voltammetry technique. Interestingly, this senor shows excellent selectivity towards CBZ due to the formation of substantial interactions between SCSPPy and CBZ, as demonstrated by molecular simulation studies. Furthermore, this sensor can precisely monitor CBZ in actual fruit and river water samples with satisfactory results. This study sheds light on the design and synthesis of sustainable hydrophilic CPs in the fabrication of sensors.