Reduced graphene oxide/multi-walled carbon nanotubes/prussian blue nanocomposites for amperometric detection of strong oxidants

This work proposes an entirely chemical synthesis of reduced graphene oxide, carbon nanotubes, and Prussian blue transparent self-assembly film through the interfacial method on the ITO substrate. We achieve morphological and particle size control of the Prussian blue nanoparticles by a slow-release mechanism in the reaction medium using sodium citrate and controlled acid addition. The obtained electrode was characterized by Raman spectroscopy and electrochemical impedance spectroscopy (EIS). The enhanced Prussian blue electrochemical stability in the neutral and alkaline medium due to carbon structures interaction was observed through voltammetric measurements. Strong oxidants molecules as hydrogen peroxide and chlorine are extensively used as bleachers, disinfectants, sanitizers, and other applications. Their presence in water is an important parameter for its drinking and disposal quality, therefore a rapid, precise, versatile and low-cost sensor is a demand on the field. A selective electrochemical sensor for the determination of H2O2 and free chlorine was proposed using batch injection analysis (BIA) with amperometric detection. The system showed good analytical linearity (0.999 and 0.997) and provided low LOD values 8.7 and 2.1 μmol L−1) to H2O2 and free chlorine, respectively. Hydrogen peroxide and free chlorine were determined in two complexes matrixes, such as body hair lightning lotion and tap water, respectively.