H2O2 detection in alkaline medium by Batch Injection Analysis using Prussian blue/carbon nanotubes/reduced graphene oxide film

The PB/CNTs/rGO film was synthetized by the interfacial method1 from a 10 mmol L-1 K3[Fe(CN)6], 9 mmol L-1 FeSO4 and 17 mmol L-1 sodium citrate aqueous solution and a dispersion containing 0.15 mg of MWCNT and 2.0 mg of rGO in toluene kept under magnetic stirring for 24 hours. The synthesis of Prussian blue is controlled by the addition of 100 μL nitric acid 14,5 mol L-1. The interaction between the Prussian blue nanoparticles and the carbon structures enhanced electrochemical stability of the film, with no significant decay of current after application of 50 cycles. Figure 1-a shows cyclic voltammogram of PB/CNT/rGO evidencing the catalytic activity of the film to reduce H2O2. Figure 1-b presents the analytical curve obtained after successive injections of H2O2, highlighting that the nanocomposite film enabled the detection of H2O2 at high pH values, despite the limitations of using alkaline medium, as described in previous work in literature. 2 This method has great benefits such as repeated analysis using a small area of film. Additional studies are being done to analyze the effect of interferers and viability of others molecules that require high pH values to be detected.