FRET-PET regulated semiconducting polymer dots for ultrasensitive and portable ratiometric detection of benzoyl...

Benzoyl peroxide (BPO) is widely used in polymer manufacturing, food processing and pharmaceutical products. However, its extensive application has raised significant safety concerns, including potential explosiveness, acute toxicity to aquatic organisms and carcinogenic risks, thereby increasing the demand for portable detection and accurate quantification methods. Herein, we report a ratiometric fluorescent probe based on PFBT/PFO-DBT polymer dots (Pdots), which exhibit strong red fluorescence owing to efficient fluorescence resonance energy transfer (FRET) from PFBT to PFO-DBT within the Pdots. Upon exposure to BPO, benzoyloxy radicals generated from BPO in the presence of Pdots selectively accept electrons from the excited PFBT donor, triggering a photoinduced electron transfer (PET) process that suppresses FRET and induces a pronounced ratiometric fluorescence response. The coupled FRET-PET regulation enables sensitive BPO quantification with a low limit of detection of 8.5 nM, excellent selectivity and anti-interference capability, as well as satisfactory recoveries and good agreement with high-performance liquid chromatography (HPLC) results. Furthermore, integration of the Pdots into sodium alginate hydrogel microspheres affords a portable sensing platform that is compatible with smartphone-based colorimetric analysis. This work establishes a novel design strategy based on regulated energy and charge transfer in semiconducting polymer nanomaterials for portable and reliable BPO sensing.