RESUMO
A new simple and efficient oligothiophene-based colorimetric and ratiometric fluorescent probe has been developed for highly sensitive and fast detection of Hg2+ in water, soil and seafood. The probe 5-(1,3-dithiolan-2-yl)-2,2':5',2â³-terthiophene 3â¯TS can selectively detect Hg2+ via the Hg2+-promoted deprotection reaction of thioacetals, which caused a remarkable color change from colorless to yellow and a strong fluorescence enhancement with emission color varying from blue to yellow, enabling naked-eye detection of Hg2+. The probe shows high sensitivity with the detection limit down to 1.03â¯×â¯10-8â¯M. Visual color changes of 3â¯TS were observed on filter paper and TLC testing strips when they were impregnated on testing strips and immersed in Hg2+ solution. Moreover, the probe 3â¯TS has been successfully used to rapidly detect trace amounts of hazardous Hg2+ ions in tap, distilled, river and lake water, cropland soil, fish, shrimp and kelp samples with acceptable results and good recoveries.
Assuntos
Colorimetria , Corantes Fluorescentes/química , Contaminação de Alimentos/análise , Mercúrio/análise , Poluição Química da Água/análise , Animais , Cromatografia em Camada Fina , Crustáceos , Peixes , Kelp , Teoria Quântica , Alimentos Marinhos/análise , Solo/químicaRESUMO
An oligothiophene-based colorimetric and ratiometric fluorescence dual-channel cyanide chemosensor 3 T-2CN was reported. Sensor 3 T-2CN showed both naked-eye recognition and ratiometric fluorescence response for CN- with an excellent selectivity and high sensitivity. The sensing mechanism based on the nucleophilic attack of CN- on the vinyl CC bond has been successfully confirmed by the optical measurements, 1H NMR titration, FT-IR spectra as well as the DFT/TD-DFT calculations. Moreover, the detection limit was calculated to be 0.19µM, which is much lower than the maximum permission concentration in drinking water (1.9µM). Importantly, test strips (filter paper and TLC plates) containing 3 T-2CN were fabricated, which could act as a practical and efficient solid state optical sensor for CN- in field measurements.