PEDOT:PSS/AuNPs/CA modified screen-printed carbon based disposable electrochemical sensor for sensitive and selective determination of carmine

A PEDOT:PSS/AuNPs/CA modified screen-printed carbon based disposable electrochemical sensor for sensitive and selective determination of carmine was studied. Enhanced electrode conductivity was achieved via a 3-step process: (i) construction of a conductive polymer (PEDOT: PSS) on a disposable screen-printed carbon electrode (SPCE) (ii) electropolymerization with gold nanoparticles (AuNPs) and (iii) modification with positively charged β-mercaptoethylamine (CA) in acidic solution using an Au S bond. The prepared nanomaterials were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectrum analysis (EDX). The properties of the resulting sensor were examined by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). Experimental parameters associated with optimal detection conditions such as modes of electrode modification, ratio of PEDOT:PSS, pH of electrolyte, number of turns used for AuNPs polymerization, and CA concentrations were evaluated. The data revealed that the prepared sensor had a low detection limit (6.05 × 10 −9  mol/L) and could achieve linearity over a wide range of concentration (9.0 × 10 −9 to 3.9 × 10 −6  mol/L), thereby meeting the requirements for analysis of trace carmine. The reliability of our technique for practical applications was demonstrated by analyzing carmine in spiked beverages.