A Portable Smartphone-assisted Sensor for Detection of Iodate Based on Triphenylamine Oligomer

The development of efficient and portable sensors for iodate detection is of significant importance. Herein, a novel oligomer (DAPF) incorporating triphenylamine and 4,5-diazafluorene units was synthesized and developed as a selective fluorescent probe for iodate (IO₃^-) under strongly acidic conditions (pH = 1). The optical properties of DAPF were thoroughly investigated, revealing a large Stokes shift and a distinct "turn-on" fluorescence response upon acidification. The probe exhibited excellent selectivity and sensitivity towards IO₃^- over other common anions, with a low detection limit of 3 × 10^- 8 M. The quenching mechanism was elucidated to involve the deprotonation of the protonated DAPF by IO₃^- driven by their difference in pKa, as supported by spectroscopic studies and theoretical calculations. Moreover, a portable polyvinyl alcohol hydrogel sensor embedded with DAPF was fabricated, enabling visual and real-time detection of IO₃^- under UV light. This work presents a promising probe for IO₃^- detection and offers a feasible strategy for designing practical sensing platforms for on-site environmental monitoring.