Optimization of silver nanoparticles modified pencil graphite electrodes via altering sputtering condition and addition of graphene

Pencil graphite electrodes (PGEs) were modified by diverse assemblies of silver nanoparticles (AgNPs) via the vacuum sputtering approach and used for rapid and sensitive detection of hydrogen peroxide (H2O2). 32 PGEs were modified under different stimulation currents and sputtering times to determine the optimal sputtering condition. The voltammetric behavior of modified electrodes was evaluated toward hydrogen peroxide reduction and the electrode modified at 10 mA and 10 s had the highest peak current (I-p) in 0.1 M phosphate buffer solution (pH 5.8) and in the presence of 1.6 mM H2O2. Analytical techniques, including field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy and atomic force microscopy were also utilized for characterizing the modified electrodes. Thereafter, sputtering at the optimum condition was done on a PGE modified by graphene, which led to exhibiting a higher value of I-p compared to the optimal modified PGE. The current response of the sensor was linear between H2O2 concentrations of 0.1 and 8.0 mM and the limit of detection was estimated to be 0.21 mu M at a signal-to-noise ratio of 3. In addition, the optimal modified electrode showed high sensitivity upon the addition of adenine, uric acid, and dopamine, proving that these compounds cannot interfere with the detection of H2O2 at a constant potential of -0.65 V vs. Ag/AgCl (pH 5.8). (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

Pencil graphite electrodes modified with silver nanoparticles were used for rapid and sensitive detection of hydrogen peroxide. The sensor showed a linear response within a certain concentration range and exhibited high selectivity towards interfering substances.