Fluorescent PVP-g-chitosan polymer probes for the recognition of 4-nitrophenol

Abstract

Natural polymer chitosan has many advantages, but the poor solubility limits its application. In this study, chitosan derivatives soluble in DCM, DMF, DMSO, H2O and other solvents were developed by introducing side chains into chitosan (CS). In addition, the fluorescent group on the side chain makes the chitosan derivative have the ability to detect 4-nitrophenol (4-NP). Firstly, a chain transfer agent containing C C (N3-NS) was synthesized with naphthalimide as the fluorescence unit. Then, using AIBN as initiator, an extensively soluble polymer with fluorescent moiety TP-NVP was synthesized by reversible addition-fragmentation chain transfer polymerization (RAFT) method using monomer N-vinyl pyrrolidone (NVP). Finally, the C C of TP-NVP was used to react with –NH2 on CS to prepare PVP-g-chitosan, so that more CS was “pulled” by TP-NVP into the solvent. The solubility of the synthesized CS-PVP probe can be adjusted by adjusting the amount of NVP, up to 17.6 mg/mL. At the same time, the synthesized CS-PVP had a good detection effect on 4-NP, and the detection limit (LOD) was 0.054 μM. The HOMO-LUMO energy level of the probe was calculated by cyclic voltammetry (CV). In addition, CS-PVP was successfully loaded on a low background fluorescent test paper to achieve real-time visual intelligent determination of 4-NP in real samples with the help of a color scanning APP of a smartphone.