Off–on fluorescent polyanthracene for recognition of ferric and fluoride ions in aqueous acidic media: application in pharmaceutical and environmental analysis
Abstract
Fluorescent polyanthracene prepared by a chemical oxidative route was shown to sense ferric ions (Fe3+) in aqueous acidic solutions. The fluorescence titration indicates that the intensity of fluorescence of the polyanthracene (PAT) was gradually quenched by the successive addition of an Fe3+ ion solution (‘Off-fluorescence’). The fluorescence quenching data fit well into the conventional Stern–Volmer relationship. A mechanism of Photoinduced Electron Transfer (PET) is proposed to explain the observed ‘Off fluorescence’ state of the PAT. Based on the strong affinity of Fe3+ to F− ions, the mixture of polyanthracene–F− ions exhibiting ‘On fluorescence’, could behave as a fluorescent ‘On type probe’. Thus a method using a single probe for the detection of both Fe3+ and F− ions is developed using a fluorescence ‘Off–On’ approach, and is successfully applied for the determination of these ions in commercial samples.