A highly sensitive hydrogen peroxide sensor based on (Ag–Au NPs)/poly[ o -phenylenediamine] modified glassy carbon electrode

Antioxidant-rich brilliant polymeric nanocomposites for quick and efficient non-enzymatic hydrogen peroxide sensor

In our current research, a new type of functional nanocomposites known as poly(methyl methacrylate/N,N-dimethyl aminoethylmethacrylate/(E)-2-cyano-N-cyclohexyl-3 (dimethylamino) acrylamide) [poly(MMA/DMAEMA/CHAA)] has been developed. These nanocomposites were created using microemulsion polymerization in conjunction with synthesized titanium dioxide (TiO2), and vanadium pentoxide (V2O5) nanoparticles. To understand the physio-chemical characteristics of the poly(MMA/DMAEMA/CHAA) and the metal oxide nanoparticles (MOs) integrated within them, various analytical techniques were employed. These techniques included Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR), X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and electrical approaches such as cyclic voltammetry (CV) and electrical impedance spectra (EIS). Based on the TEM results, nanospheres with a well-defined structure were developed for both the pure polymer and its composite with sizes ranging from 45 to 75 nm. All the TiO2 and V2O5-based nanocomposites showed significantly enhanced electrical attributes, with capacitance values surpassing those of the poly(MMA/DMAEMA/CHAA) nanosphere assemblies by a considerable margin. As a result, both direct electron transfer and direct hydrogen peroxide identification were evaluated for the nanocomposites. The amperometry results demonstrated a lower detection limit of 0.0085 μM and a rapid linear sensitivity in the range of 1 to 800 μM. The greatly improved electrolytic qualities of these nanocomposites make them suitable for various applications in fields such as battery storage, sensors, and biosensors.

Improvement of amperometric transducer selectivity using nanosized phenylenediamine films

In this work, we studied the conditions of deposition of a semipermeable polyphenylenediamine (PPD)-based membrane on amperometric disk platinum electrodes. Restricting an access of interfering substances to the electrode surface, the membrane prevents their impact on the sensor operation. Two methods of membrane deposition by electropolymerization were compared-at varying potential (cyclic voltammetry) and at constant potential. The cyclic voltammetry was shown to be easier in performing and providing better properties of the membrane. The dependence of PPD membrane effectiveness on the number of cyclic voltammograms and phenylenediamine concentration was analyzed. It was shown that the impact of interfering substances (ascorbic acid, dopamine, cysteine, uric acid) on sensor operation could be completely avoided using three cyclic voltammograms in 30 mM phenylenediamine. On the other hand, when working with diluted samples, i.e., at lower concentrations of electroactive substances, it is reasonable to decrease the phenylenediamine concentration to 5 mM, which would result in a higher sensitivity of transducers to hydrogen peroxide due to a thinner PPD layer. The PPD membrane was tested during continuous operation and at 8-day storage and turned out to be efficient in sensor and biosensors.