ABSTRACT
A benzothiazole-based fluorescent and colorimetric chemosensor BZD ((E)-2-(benzo[d]thiazol-2-yl)-5-((4-(diethylamino)-2-hydroxybenzylidene)amino)phenol) was applied for detecting ClO-. BZD showed fluorescence quenching and color variation for ClO- via oxidative reaction between ClO- and the imine bond. It could effectively detect ClO- over various competitive analytes. Detection limit for ClO- was calculated to be 1.74 µM by fluorescent method and 16.44 µM by colorimetric one, respectively. Additionally, BZD could be utilized for sensing ClO- in zebrafish, real water sample and paper strip. The photophysical characteristics and sensing mechanism of BZD to ClO- were studied by fluorescent and UV-visible spectroscopy, NMR titration, and ESI-mass spectrometry.
Subject(s)
Colorimetry , Hypochlorous Acid , Animals , Benzothiazoles , Fluorescent Dyes , Water , ZebrafishABSTRACT
SBOD (sodium (E)-2-(3-[5-bromothiophen-2-yl]-3-oxoprop-1-en-1-yl)-4,6-dichlorophenolate) was designed and synthesized as a chalcone-based fluorescent turn-on chemosensor for Mg2+ and Cd2+ . SBOD selectively detected Mg2+ and Cd2+ through the increase in effective fluorescence. Detection limits of SBOD for Mg2+ and Cd2+ were calculated to be 3.8 µM and 2.9 µM, respectively. The binding modes of SBOD for Mg2+ and Cd2+ were determined to be 1:1 by ESI-MS and Job plot. Association mechanisms for SBOD to Mg2+ and Cd2+ were illustrated by ESI-MS, UV-vis, fluorescence spectroscopy, and calculations.
Subject(s)
Chalcone , Chalcones , Cadmium , Fluorescent Dyes , Spectrometry, FluorescenceABSTRACT
We synthesized an original reversible colorimetric chemosensor PDJ ((E)-9-((2-(6-chloropyridazin-3-yl)hydrazono)methyl)-2,3,6,7-tetrahydro-1H,5H-pyrido[3,2,1-ij]quinolin-8-ol) for the detection of F-. PDJ displayed a selective colorimetric detection to F- with a variation of color from colorless to yellow. Limit of detection of PDJ for F- was calculated as 12.1 µM. The binding mode of PDJ and F- turned out to be a 1:1 ratio using Job plot. Sensing process of F- by PDJ was demonstrated by 1H NMR titration and DFT calculation studies that suggested hydrogen bond interactions followed by deprotonation. Moreover, the practicality of PDJ was demonstrated via a reversible test with TFA (trifluoroacetic acid).
ABSTRACT
Hypochlorite is used as a water disinfectant and it is also produced by biological organisms. Its detection and quantification is important and could lead to its mechanism of reactivity in cells. We have synthesized a new fluorescence sensor for hypochlorite based on bithiophene and furan-carbohydrazide. The sensor shows increased fluorescence as a function of hypochlorite and is selective for hypochlorite. Fluorescence enhancement due to hypochlorite is observed when the sensor is used in aqueous solutions at neutral pH values. Using the sensor, the detection limit for hypochlorite is 4.2 µM, making the sensor practical to determine hypochlorite in water. Applying the sensor to aide in the detection of hypochlorite in zebrafish, showed localization of ClO-/HClO in the air bladders and eyes of zebrafish.