Rapid and reliable determination of p-nitroaniline in wastewater by molecularly imprinted fluorescent polymeric ionic liquid microspheres.

Rapid and efficient detecting trace amount of environmental p-nitroaniline (p-NA) is in urgent need for security concerns and pollution supervision. In this work we report the use of molecularly imprinted polymeric ionic liquid (MIPIL) microspheres to construct recognizable surfaces for detection of p-NA through fluorescence quenching. The p-NA imprinted microspheres are synthesized by precipitation polymerization upon co-polymerization of 3-(anthracen-9-ylmethyl)-1-vinyl-1H-imidazol-3-ium chloride (Fluorescent IL monomer) with ethyleneglycol dimethacrylate (EGDMA). The electron-rich group alkenyl imidazole in IL functional monomer can dramatically improve the emission of anthracene fluorophore and the π-π stacking, electronic, and hydrogen bond between p-NA and MIPIL can efficiently enhance the selective recognition force. The as-synthesized MIPIL microspheres present spherical shape, high fluorescence emission intensity and specific recognition, which showed rapid detection rate (1min), stable reusable property (at least 4 time recycles), wonderful selectivity over several structural analogs, wide linear range (10nM to 10M) with a correlation coefficient of 0.992, and excellent sensitivity (LOD, 9nM). As synthesis and surface functionalization of MIPIL microspheres are well established, the methods reported in this work are facile, rapid and efficient for monitoring p-NA in environmental wastewater.