Highly sensitive and recognizable detection for trifluralin with alkyl-decorated fluorescent porous polymers

The sensing materials and portable devices with high sensitivity and specific recognition are urgently demanded for monitoring the pesticide residue in soil, water and food. Herein, two fluorescent porous polymers with carbazole-based chromophores decorated by n-butyls are synthesized through A3 + B2 and A3 + B4 condensation polymerizations, respectively. The hierarchical pores ranging from ultramicropore to mesopore are adjustable by varying the crosslinking density in the networks. The fluorescent quenching coefficient and limit of detection for trifluralin exceptionally reach 4.57 × 105 M−1 and 6.0 ppb, and the polymers exhibit ultra-sensitive recognizable ability for trifluralin in water. The quenching efficiencies for trifluralin in water, aqueous solutions of various cations and anions, vegetable juice and soil filtrate remain nearly the same. In particular, the fabricated polymer plates are portable and show visual fluorescent quenching for trifluralin solution at an extremely low concentration, and the plates can be easily recovered and repeatedly used. The results revealed in this manuscript are helpful for deeply understanding the effects of porosity parameters and alkyl-decorated chromophore groups on the sensitive and recognizable sensing mechanism for trifluralin.