A recyclable, fluorescent, and colorimetric sensor for fluoride anion in water using a crosslinked polymer functionalized with hydroxyl quinolinium

This study aimed to develop a recyclable, fluorescent, and colorimetric sensor for fluoride anion (F−) in aqueous media with fast response, good selectivity, and high sensitivity. A crosslinked polymer CpA1T5 was designed and synthesized as a sensor using (E)-1-allyl-4-((4-hydroxylphenyl)vinyl) quinolinium bromide as functional monomer, trimethylolpropane trimethacrylate as crosslinker, and azobisisobutyronitrile as initiator. When F− was introduced to the CpA1T5 suspension in deionized water, a change in color from gray to yellow and fluorescence enhancement accompanied with a redshift from 531 nm to 540 nm of fluorescence emission were immediately observed. This F− sensor can be recycled many times, making it cost efficient and beneficial to the environment. Analytical application of CpA1T5 to measure F− concentration in two commercial mouthwash samples was explored with good accuracy.