Synthesis of the fluorescent polymer containing pyrene and its application in the detection of tea polyphenol

Tea polyphenol (TP) is used as a food additive to inhibit lipid peroxidation reactions and extend shelf life, but excessive intake can affect the human immune system. Therefore, developing effective TP detection is significant. Here, pyrene-based polyimide (Py-PI) was synthesized by one-step condensation copolymerization. This polyimide possessed excellent solubility and photoluminescence due to the introduction of pyrene-conjugated groups. It could be used as fluorescent probe for TP detection in solution. In addition, Py-PI fluorescent test paper with different morphology were prepared by electrospinning. As the concentration of the spinning solution was 15 wt%, the bead-like porous polymer electrospun membrane displayed excellent surface wettability which could make the water droplet completely penetrate into the sample within 6 min. The fluorescence enhancement phenomenon could be observed for 5 × 10 −6 mg/mL TP solution on Py-PI test paper. Furthermore, interference investigation of pH on test paper indicated that the sample exhibited a relatively stable fluorescence “turn-on” response in acidic conditions. This work provides a convenient and rapid detection of TP antioxidant in the future.