Studies on quenching of fluorescence of reagents in aqueous solution leading to an optical chloride-ion sensor

doi:10.1016/S0925-4005(97)80228-6

Sensors and Actuators B: Chemical

Volume 39, Issues 1–3, March–April 1997, Pages 330-333

https://doi.org/10.1016/S0925-4005(97)80228-6 Get rights and content

Abstract

The sensitivity of quinoline- and acridine-type indicators towards the detection of low levels of chloride ions in aqueous and amine-doped media, by fluorescence quenching, is reported in this paper. Solution studies are based on the fluorescence of quinine sulphate, acridine and 3-(6-methoxyquinolino) propanesulphonate (SPQ) and the fluorescence response of these indicators has been examined at different pH values and at various chloride ion concentrations in aqueous media.

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This indicates the feasibility of the collisional mechanism of fluorescence quenching by chloride-ions. The observed drastic quenching of fluorescein emission in the solutions with high concentration of hydrochloric acid conforms to the previous studies, where the fluorescence quenching of organic compounds by chlorides was reported [26,27]. Although the spectral properties of fluorescein were intensively investigated since the very beginning of fluorescence spectroscopy, we tried to bring some new insights concerning the nature of the excitation relaxation in the protolytic/tautomeric forms existing at equilibrium in strongly acidic solutions (pH < 3.5).
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Schematic of the sensing mechanism, spectrofluorimetric analysis, and calibration curve of the lactate sensor are depicted in Fig. S8, Fig. 2b, and Fig. 3b, respectively. Chloride: George Stokes described the first report regarding fluorescence quenching of a fluorophore in the presence of a halide in 1869 as he observed fluorescence quenching of quinine in sulfuric acid after the addition of hydrochloric acid (Martin and Narayanaswamy, 1997). This process is now referred to as dynamic fluorescence quenching and known to follow Stern-Volmer kinetics.
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Studies on quenching of fluorescence of reagents in aqueous solution leading to an optical chloride-ion sensor

Abstract

Anal. Chim. Acta

Sensors and Actuators B

Sensors and Actuators B

Talanta

Biophys. J.

Anal. Chim. Acta

Photometric and Fluorometric Methods of Analysis—Nonmetals

Colourimetric Determination of Non Metals