Fine-tuning benzazole-based probe for the ultrasensitive detection of Hg2+ in water samples and seaweed samples

Abstract

Developing potentially toxic metal ion probes is significant for environment and food safety. Although Hg²⁺ probes have been extensively studied, small molecule fluorophores that can integrate two applications of visual detection and separation into one unit remain challenging to access. Herein, by incorporating triphenylamine (TPA) into tridentate skeleton with an acetylene bridge, 2,6-bisbenzimidazolpyridine-TPA (4a), 2,6-bisbenzothiazolylpyridine-TPA (4b) and 2,6-bisbenzothiazolylpyridine-TPA (4c) were first constructed, expectably showing distinct solvatochromism and dual-state emission properties. Since the diverse emission properties, the fluorescence detection of 4a-4b can be achieved with an ultrasensitive response (LOD = 10^-11 M) and efficient removal of Hg²⁺. More interestingly, 4a-4b can not only be developed into paper/film sensing platform, but also reliably detect Hg²⁺ in real water and seaweed samples, with recoveries ranging from 97.3% to 107.8% and a relative standard deviation of less than 5%, indicating that they have excellent application potential in the field of environmental and food chemistry.

Keywords: Coordination-removal; Dual-state emission; Hg(2+) detection; Tridentate skeleton; Triphenylamine.