Non-Enzymatic Electrochemical Sensing of Glucose with a Carbon Black/Polyaniline/Silver Nanoparticle Composite

The present work describes the synthesis of an electroactive nanocomposite consisting of carbon black (CB) and polyaniline (PANI) obtained by in situ oxidative polymerization. Monomer P1 was used as a polyaniline precursor. P1 has surfactant properties that allow obtaining core–shell structures dispersed in an aqueous medium. The nanocomposite, together with silver nanoparticles (AgNPs) as an electrocatalytic element, was used to modify the surface of a glassy carbon electrode (GCE) for glucose detection. Electroactive areas were calculated using the Randles–Sevick equation. The results showed that the CB-PANI.1-1/AgNP nanocomposite exhibited a larger electroactive surface area (0.3451 cm2) compared to AgNP alone (0.0973 cm2) or the CB-PANI.1-1 composite (0.2989 cm2). Characterization of CB-PANI.1-1/AgNP, by cyclic voltammetry in the presence of glucose, showed a new oxidation peak with a maximum current close to 0.7 V due to the oxidation of glucose to gluconolactone. The amperometry test at 0.7 V showed a linear response with R2 of 0.999 as a function of the analyte concentration. The glucose sensor presented a linear detection range of 1 to 10 mM, a sensitivity of 41 µA mM−1 cm−2, and a limit of detection (LOD) of 520 µM.