Synthesis of dual-responsive, highly fluorescent, non-conjugated polymer dots for Fe 3+ detection

Highly fluorescent non-conjugated polymer dots (PDs) were synthesized by an aqueous synthetic route using a hydrothermal method from polyester prepared with PEG and di-anhydride EDTA (DA-EDTA). The synthesized PDs display strong blue fluorescence with a high quantum yield (QY) of 45% in water and more than 45% in ethanol, dimethyl sulfoxide, N, N-dimethyl formamid, and acetone. The optical and structural properties of the PDs were investigated by UV–Vis, fluorescence spectrophotometry, EDX, FTIR, SEM, TEM, AFM, and DLS. The PDs were used as a sensitive fluorescence probe for Fe ³⁺ ions detection, with a low detection limit of 1.28 µM. The linear range in which fluorescent intensity decreases with increasing Fe ³⁺ is 0-120 µM. Besides, in the range of 20℃ to 70 ℃, fluorescent intensity declines with increasing temperature. Therefore, it can also be used as a thermometer. The spike recovery test confirmed the practicality of the method for the analysis of Fe ³⁺ ions in tap water samples.