A Silver-Loaded Exfoliated Graphite Nanocomposite Anti-Fouling Electrochemical Sensor for Bisphenol A in Thermal Paper Samples

Tebogo R Tsekeli; Tsholofelo I Sebokolodi; Hassan Karimi-Maleh; Omotayo A Arotiba

doi:10.1021/acsomega.0c05836

A Silver-Loaded Exfoliated Graphite Nanocomposite Anti-Fouling Electrochemical Sensor for Bisphenol A in Thermal Paper Samples

ACS Omega. 2021 Apr 2;6(14):9401-9409. doi: 10.1021/acsomega.0c05836. eCollection 2021 Apr 13.

Authors

Tebogo R Tsekeli¹, Tsholofelo I Sebokolodi¹, Hassan Karimi-Maleh^{1

2}, Omotayo A Arotiba^{1

3}

Affiliations

¹ Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa.
² University of Electronic Science and Technology of China, Chengdu 611731, China.
³ Centre for Nanomaterials Science Research, University of Johannesburg, Johannesburg 2028, South Africa.

Abstract

Silver nanoparticles (AgNPs) were synthesized separately and loaded onto the expanded layers of exfoliated graphite (EG) to form a silver nanoparticle-exfoliated graphite nanocomposite (AgNPs-EG). The AgNPs-EG was compressed into a pellet (0.6 cm in diameter) and used to prepare an electrochemical sensor for bisphenol A (BPA) in standard samples and in thermal paper. The synthesized materials were characterized by ultraviolet-visible spectrophotometry, X-ray diffraction spectroscopy, scanning electron microscopy, and energy-dispersive X-ray. The electrochemical behavior of BPA on the AgNPs-EG sensor was investigated by cyclic voltammetry and square wave voltammetry. Under optimized experimental conditions, the oxidation peak current was linearly proportional to bisphenol A concentrations in the range from 5.0 to100 μM, with a coefficient of determination (R² ) of 0.9981. The obtained limit of detection of the method was 0.23 μM. The fabricated sensor was able to overcome electrode fouling with good reproducibility (RSD = 2.62%, n = 5) by mechanical polishing of the electrode on emery paper. The proposed method was successfully applied to determine bisphenol A in thermal paper samples and demonstrated good accuracy of 93.1 to 113% recovery.