Colorimetric Chemosensors for selective detection of arsenite and arsenate: DFT studies and application in water
C V Nithin1, K Nagaraj1, Darshak R Trivedi1
1Supramolecular Chemistry Laboratory, Department of Chemistry, National Institute of Technology, Karnataka (NITK), Surathkal, Mangalore, Karnataka 575025, India.
Abstract:
The study focuses on developing colorimetric chemosensors that selectively detects arsenite (AsO2-) and arsenate (AsO43-) anions. Three furan-based colorimetric chemosensors, NCV1, NCV2 and NCV3 were synthesized and the compounds were characterized using FT-IR, 1H NMR, 13C NMR, and LC-MS techniques. The chemosensors were tested for their capacity to detect various anions and cations in dimethyl sulfoxide (DMSO) as solvent and showed significant selectivity for arsenite and arsenate ions. These colorimetric findings were further validated through UV-Vis titrations. Binding constants for arsenite (AsO₂-) and arsenate (AsO₄3-) were determined using the Benesi-Hildebrand plots. The limit of detection determined from the calibration curve for NCV1 was 0.19 ppm for arsenite and 0.15 ppm for arsenate. The potential interference from other anions for arsenite detection and the stability of the chemosensors at different pH levels were also evaluated using UV-Vis spectroscopy. The interference studies revealed only minimal interference by other anions. Additionally, the binding mechanism was confirmed to involve hydrogen bonding followed by NH deprotonation by cyclic voltammetry, 1H NMR titration, and computational analysis. The application of synthesized chemosensors for detecting arsenite in various water samples was also investigated.
Related Concept Videos
Atomic Absorption Spectroscopy: Lab
Solutions containing organic solvents, such as low-molecular-mass alcohols, esters, or ketones, enhance absorbances by increasing...
Precipitation Titration: Endpoint Detection Methods
In the Volhard method, a standard excess of AgNO3 is first added to the...
Effects of EDTA on End-Point Detection Methods
In the visual method, metal-ion indicators (metallochromic dyes), which have distinct colors in their free and complex forms, are added to the mixture to signal the titration's end point. They form stable complexes with metal ions, but these complexes are weaker than the corresponding metal–EDTA complexes. As a...
Precipitation and Co-precipitation
Photoluminescence: Applications
Complexometric Titration: Ligands


