A pyrazole-based colorimetric chemosensor for selective arsenate detection in the presence of cyanide interference
Year: 2026
Type: article
Abstract: A simple pyrazole-based colorimetric chemosensor, 4( E )-1-(4-((2-(2,4-dinitrophenyl)hydrazinylidene)methyl)phenyl)-1H-pyrazole ( PY-09 ), was developed for the selective detection of arsenate (AsO 4 3− ) and cyanide (CN − ) ions through distinct optical responses. The free probe exhibited a yellow colour, which changed to magenta upon interaction with either AsO 4 3− or CN − , enabling rapid naked-eye detection. UV–Vis absorption studies revealed a bathochromic shift from 403 nm to 507 nm for AsO 4 3− and to 508 nm for CN − . The probe demonstrated high sensitivity, with detection limits of 0.99 μM for AsO 4 3− and 0.29 μM for CN − . Job's plot analysis indicated binding stoichiometries of 1:1 for both AsO 4 3− and CN − , while the corresponding association constants were determined to be 2.14 × 10 5 M −1 and 4.4 × 10 4 M −1 , respectively. The sensing process was reversible upon the addition of trifluoroacetic acid (TFA). Furthermore, hydrogen peroxide was successfully employed as a masking agent to selectively eliminate cyanide interference, enabling the specific detection of arsenate ions. The practical applicability of PY-09 was validated through successful analysis of real water samples, demonstrating excellent recovery and reliability. These findings highlight PY-09 as a simple, sensitive, and cost-effective colorimetric chemosensor, demonstrating its potential for colorimetric arsenate detection in water samples.
Source: Results in Chemistry
Authors: U. Mithra, V. Vijayakumar, S. Sarveswari
Institution: Vellore Institute of Technology University
Language: English
Subfield: Spectroscopy
Field: Chemistry
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,870
OpenAlex ID: W7225403345