Self-assembled gold nano islands for precise electrochemical sensing of trace level of arsenic in water

Abstract

Trace level detection of Arsenic in groundwater is one of the major step in the detoxification of drinking water. Accumulation of Arsenic in various parts of the human body through drinking water is a serious health hazard across the world including India. The present experiment describes the template free growth of gold nano island(AuNis) on the ITO surface to integrate with 1,4-dithiothreitol(DTT) for the construction of electrochemical sensor (DTT/AuNis/DTH/Auseed/APTMS/ITO) for trace level arsenic detection in water. Unique recognition of As3+offered by DTT, a ligand having –SH and –OH functional groups, and enhanced electrochemical signal originated from AuNis self-assembled on the ITO surface were exclusively harnessed for trace level detection of Arsenic (As3+) in water. The developed DTT/AuNis/DTH/Auseed/APTMS/ITO electrode was characterized using UV–Visible spectroscopy, Field Emission Scanning Electron Microscope (FESEM), Atomic Force Microscopy (AFM), Raman Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), and Cyclic Voltammetry (CV). Wide linearity (R2 = 0.97) has been achieved for a gamut of arsenic concentration from 0.1 to 100 ppb with LOD of 0.085 ppb. The developed sensor offers a good sensitivity of 4.39 mA ppb cm−2. Interference studies were successfully performed for contaminated water samples and in presence of assorted heavy metal ions like Hg2+, Pb2+, Ni2+ and, Cr3+ using 2, 4-Pyridinedicarboxylic acid (PDCA), a sequestering agent. The developed sensor was evaluated as a sensitive, rapid, and reliable platform for the detection of As3+ in real samples offering huge potential for commercialization.