A novel benzopyran-based fluorescent sensor for the selective detection of Hg2+ ions

Abstract

A novel benzopyran-based fluorescent turn-off probe for the detection of Hg²⁺ was synthesized in two steps and characterized via¹H and ¹³C NMR, FT-IR, and HRMS spectroscopy. Its configuration was established by X-ray single-crystal diffraction. The probe exhibited high selectivity for Hg²⁺ and excellent anti-interference against other metal ions within a pH range of 4–11. Job's plots and ¹H NMR titration confirmed the formation of a 1 : 1 complex of the CPA probe and Hg²⁺, with a detection limit of 1.31 × 10⁻⁷ M. Moreover, a smartphone-assisted fluorescence-colorimetric detection platform was developed, which could monitor Hg²⁺ levels through real-time analysis.