Easily water soluble cellulose-based fluorescent probes for the detection of 4-nitrophenol

Cellulose, an abundantly available natural polymer, is generally insoluble in water or common organic solvents. In this study, fluorescent probes based on cellulose were fabricated, rendering them soluble in H2O and capable of selectively recognizing 4-nitrophenol (4-NP). Firstly, the modified cellulose with -Cl was prepared by the substitution reaction of -OH and SOCl2 on cellulose. Secondly, the reversible addition-fragmentation chain transfer (RAFT) reagent FNT with -NO2 and -CHO was obtained by reacting p-nitrophenylthiophenol with pchloromethyl benzaldehyde. It was then reacted with 2,4-dimethylpyrrole to obtain a fluoroboronodipyrrole fluorescent RAFT reagent BNT with -NO2, followed by the reduction of -NO2 to -NH2 to obtain ABT. RAFT polymerization was conducted using reagent ABT with sodium vinyl sulfonate (SVS), sodium p-styrene sulfonate (SSS), sodium allyl sulfonate (SAS) in DMF. In the polymerization process, azobisisobutyronitrile (AIBN) was used as the initiator, yielded polymers with superior water solubility. Finally, three cellulose based fluorescent probes were prepared by substitutional reaction between -Cl on cellulose and -NH2 on the as-prepared polymers. The solubility of the probes was much higher than that of the original cellulose, and it can be served as macromolecular probes for the detection of 4-NP, and applied in environmental systems.