Abstract:
Graphical Abstract
Metal Cations Mercury(II) contamination poses a serious threat to the environment and public health due to its high toxicity and bioaccumulation. In this study, we present a rationally engineered fluorescent sensor, GO@NH@DNS, prepared by covalently immobilizing dansyl chloride (DNS-Cl) onto graphene oxide (GO) through (3-aminopropyl) triethoxysilane, thereby introducing a sulfonamide (-SO2NH-) recognition site for selective Hg²? detection. The GO@NH@DNS sensor exhibited strong fluorescence at 528?nm in ethanol: water (E: W 1:1 v/v) and 512 nm in ethanol (EtOH), closely matching the TDDFT-simulated emission at 524?nm, which confirmed the successful grafting of the DNS moiety on GO. Characterization by fluorescence spectroscopy, FTIR, XRD, and SEM verified functionalization and immobilization, as indicated by the disappearance of the GO (001) reflection at 11.7° (2?), the -SO2NH- bands at 1406.19 cm?¹, and a notably roughened surface morphology. Upon exposure to Hg²?, the fluorescence intensity was markedly quenched by 79% in EtOH and 68% in E:W 1:1 v/v, while other representative cations caused negligible interference,demonstrating the high selectivity of the system. Mechanistic insights fromelectron density mapping revealed a highly localized negative charge(-0.07379 e? Å?³) and notable softness (0.719 eV?¹) at the -SO2NH- site,facilitating Hg²? coordination and explaining the efficient quenching response.Benefiting from this rational design, GO@NH@DNS displayed rapid, linear,and sensitive responses to Hg²? over the 0-35 µM range, with LODs of 0.60 µMin EtOH and 1.03 µM in E:W (1:1, v/v) and corresponding LOQs of 1.99 µMand 3.43 µM, achieving recoveries of 87.1-107.9% with RSDs below 3.6% inspiked samples. The sensor also exhibited excellent operational stability, withblank fluorescence RSDs of <0.4% in EtOH and ~1.0% in E:W (1:1, v/v), andno observable degradation over five months, establishing it as a robust, reusable,and highly selective solid-phase fluorescent platform for practical environmentalHg²? monitoring.
Page(s):
92-93
DOI:
DOI not available
Published:
Journal: 4th International Conference of Sciences “Revamped Scientific Outlook of 21st Century, 2025” , November 12,2025, Volume: 1, Issue: 1, Year: 2025
Keywords:
Graphene oxide
,
Hg2+ sensing
,
Dansyl chloride
,
Environmental samples
,
Fluorescence quenching