Trace level electrochemical analysis of arsenite in human serum utilising rGO/AuNPs based sensor platform

ABSTRACT

Heavy metal poisoning is the most prevalent health hazard at hazardous waste sites, affecting a large population on daily basis, with arsenite poisoning ranking third in terms of prevalence and severity. Therefore, the main objective of this study is to develop a novel, highly efficient sensor for detecting trace amounts of arsenite (As^III) in human serum by utilising reduced graphene oxide/gold nanoparticles (rGO/AuNPs) based nanocomposite structure. In this work, a screen-printed carbon electrode (SPE) was modified using rGO/AuNPs nanocomposite to detect As^III in human serum. The detection data were recorded and analysed using Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV), whereas transmission electron microscope (TEM), scanning electron microscope (SEM) as well as Fourier transform infrared (FTIR) spectroscopy were used to determine the surface morphological features and the presence of significant elements/groups in the prepared nanocomposite structure. Under the optimised conditions, the linear regression coefficient (R²) for the DPV response of the fabricated electrode (rGO/AuNPs@SPE) was observed to be 0.98. The rGO/AuNPs@SPE demonstrated remarkable sensor response for As^III with detection limits of 10 ppb via DPV in standard samples, due to the synergistic effect of rGO and AuNPs based nanocomposite. The sensitivity of the sensor was found to be 0.0142 Appb⁻¹cm⁻² for 100–1000 ppb concentration range of As^III. The rGO/AuNPs@SPE sensor also displayed good stability and reproducibility when used in As^III spiked human serum samples in which the limit of detection was observed at 100ppb. The porous structure of rGO on the sensing interface efficiently improves the electrode’s adsorption and conductivity, while citrate capped AuNPs offer the functional groups required for maximum adsorption of As^III. Hence, the developed electrochemical sensor (rGO/AuNPs@SPE) can be used very precisely and reliably in various applications for trace level detection of As^III in human serum.

KEYWORDS:

• Gold nanoparticles
• reduced graphene oxide
• arsenite
• differential pulse voltammetry
• cyclic voltammetry

Acknowledgments

The authors are grateful to Ms. Deepa Verma, Director, GNCT of Delhi Forensic Science Laboratory and Sri. K.C. Varshney, Head of Office, Regional Forensic Science Laboratory, Chanakya Puri, and Dr. A.K. Jaiswal (Chemist, Department of Forensic Medicine & Toxicology, AIIMS, New Delhi) for their profound support and encouragement.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Credit authorship contribution statement

Shalvi: Methodology, Conceptualization, Formal analysis, Investigation, Writing original draft. Varsha Gautam: Methodology, Formal Analysis, Data curation. Kanak Lata Verma: Resources, Supervision, Validation, Visualisation. Suman: Visualisation, Validation, Supervision, Vinod Kumar Jain: Funding acquisition. Administration, Supervision. Avshish Kumar: Results analysis and explanations, Supervision.