A DIE responsive fluorescent probe for phthalate and its application in test paper and hydrogel detection platforms

Abstract

Phthalates, classified as priority environmental contaminants, have driven intensive methodological development for environmental monitoring due to their well-documented endocrine-disrupting effects. Despite these imperatives, the design of optical probes for phthalate detection remains challenging probably due to the lack of suitable functional groups/sensing mode. Additionally, the reported probes were applied in the form of suspensions, resulting in difficulties in separation and recovery during the practical applications. Addressing these limitations, we engineered an amphiphilic BODIPY derivative (BOD-Bea) featuring a bespoke molecular architecture that self-assembles into non-fluorescent aggregates in aqueous media. Upon dipentyl phthalate (DPP) binding, significant fluorescence and absorption enhancements were elicited through the mechanism of disaggregation-induced emission (DIE). From the titration experiments, both the fluorescence emission at 653 nm and absorption at 576 nm demonstrate linear correlations with DPP concentrations in the range of 0–26 μM. The calculated LODs were determined to be 0.11 μM for fluorescence detection and 1.24 μM for absorption measurement. Detailed binding mechanism reveals that the probe achieves specific DPP recognition through synergistic interactions: π–π stacking anchoring the benzene ring moiety and hydrophobic capturing of the alkyl chain. Finally, probe BOD-Bea has been successfully employed to quantify DPP in the real water samples with good recoveries. Meanwhile, two instrument-free solid sensors based on BOD-Bea (i.e., test paper and hydrogel) are fabricated to rapidly and sensitively monitor DPP. This strategy overcomes the disadvantages of complex and costly pre-treatment of traditional methods and provides a molecular design basis for rapid on-site detection.