An aminonaphthalene‐based colorimetric and fluorescent sensor for selective recognition of Fe 3+ in water

This paper describes the synthesis of poly(1‐aminonaphthalene) and its application as a chemosensor for detection of Fe 3+ using the naked eye and a fluorimetric method. The conjugated polymer was synthesized by chemical oxidative polymerization using FeCl 3 as a catalyst. The response of the polymer towards various metal ions was investigated using colorimetric detection, and ultraviolet–visible and fluorescence spectroscopies. The polymer displayed high selectivity and sensitivity towards Fe 3+ compared with other metal ions. A significant colour change from purple to yellow was observed upon addition of Fe 3+ by the naked eye. The polymer also showed a high selectivity and sensitivity ‘turn‐off’ fluorescence response towards Fe 3+ ions. A good linear response was obtained for Fe 3+ concentrations in the range 10–50 mg L −1 with a detection limit of 1.04 mg L −1 . The proposed chemosensor was applied for determination of Fe 3+ content in water samples and satisfactory results were obtained.