Fluorescence detection for H₂PO₄ ^- based on carbon dots/Fe³⁺ composite

Abstract

A novel fluorescent probe for H₂PO₄ ^- was designed and fabricated based on the carbon dots/Fe³⁺ composite. The carbon dots were synthesized by an established one-pot hydrothermal method and characterized by transmission electron microscope, X-ray diffractometer, UV-Vis absorption spectrometer and fluorescence spectrophotometer. The carbon dots/Fe³⁺ composite was obtained by aqueous mixing of carbon dots and FeCl₃, and its fluorescence property was characterized by fluorescence spectrophotometer. The fluorescence of carbon dots was quenched by aqueous Fe³⁺ cations, resulting in the low fluorescence intensity of the carbon dots/Fe³⁺ composite. On the other hand, H₂PO₄ ^- reduced the concentration of Fe³⁺ by chemical reaction and enhanced the fluorescence of the carbon dots/Fe³⁺ composite. The Stern-Volmer equation was introduced to describe the relation between the relative fluorescence intensity of the carbon dots/Fe³⁺ composite and the concentration of H₂PO₄ ^-, and a fine linearity (R ²=0.997) was found in the range of H₂PO₄ ^- concentration of 0.4-12 mM.

Keywords

H₂PO₄ ^- detection / fluorescence / carbon dots/Fe³⁺ composite

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