Fluorescent poly(tannic acid)-based nanoprobes for selective and sensitive detection of bismuth ions

Herein, blue luminescent fluorescent poly(tannic acid) nanoparticles (FPTA NPs) were fabricated through chemical degradation of poly(tannic acid) large particles using H₂O₂, and the obtained FPTA NPs exhibited excellent water dispersibility, great fluorescence stability, and relatively high quantum yield. More importantly, based on the dynamic quenching and chelation enhanced quenching effect between FPTA NPs and bismuth ions (Bi³⁺), a fluorescence method for the rapid identification and detection of Bi³⁺ was developed. With the increase of Bi³⁺, the fluorescence of FPTA NPs could be quenched gradually; the linear range was 0.2-80 μM, <i>R</i>² was 0.997, the detection limit was 13.54 nM, and the response time was as short as 10 s. The FPTA NP based nanoprobe was successfully applied for the determination of Bi³⁺ in water samples, and the recovery rate ranged from 98.18% to 105.89%, with a relative standard deviation of less than 3.48%, thereby confirming the feasibility of using FPTA NPs for detecting Bi³⁺ in real water samples.