Sensitive and Selective Determination of 2,4,6-Trichlorophenol Using a Molecularly Imprinted Polymer Based on Zinc Oxide Quantum Dots

Molecularly Imprinted Polymer-Based Sensors for Priority Pollutants

Globally, there is growing concern about the health risks of water and air pollution. The U.S. Environmental Protection Agency (EPA) has developed a list of priority pollutants containing 129 different chemical compounds. All of these chemicals are of significant interest due to their serious health and safety issues. Permanent exposure to some concentrations of these chemicals can cause severe and irrecoverable health effects, which can be easily prevented by their early identification. Molecularly imprinted polymers (MIPs) offer great potential for selective adsorption of chemicals from water and air samples. These selective artificial bio(mimetic) receptors are promising candidates for modification of sensors, especially disposable sensors, due to their low-cost, long-term stability, ease of engineering, simplicity of production and their applicability for a wide range of targets. Herein, innovative strategies used to develop MIP-based sensors for EPA priority pollutants will be reviewed.

Hollow molecularly imprinted fluorescent sensor using europium complex as functional monomer for the detection of trace 2,4,6-trichlorophenol in real water samples

As an important environmental indicator, 2,4,6-trichlorophenol (2,4,6-TCP) was proved extremely harmful to human body. In this article, hollow molecularly imprinted fluorescent polymers (@MIPs) for the selective detection of 2,4,6-TCP were devised and fabricated by sacrificial skeleton method based on SiO₂ nanoparticles. As the most innovation, highly luminescent europium complex Eu(MAA)₃phen played the role of both fluorophores and functional monomers of the MIPs. The obtained @MIPs showed monodispersity and the average particle size was around 130 nm. It had a linear fluorescent response within the concentration range 10-100 nmol L^-1 with the correlation coefficient calculated as 0.99625, and the limit of detection was identified as 2.41 nmol L^-1. The results show that Eu(MAA)₃phen as a fluorophore has high luminescent properties, and as a functional monomer, it can improve the selectivity and anti-interference performance of MIPs. Furthermore, the hollow structure made it possible that the imprinted specific recognition sites distributed on both inner and outer surfaces of @MIPs. The experimental results showed that these @MIPs could be employed to the selective detection of chlorophenols under low concentration. And this work will provide a reference for further optimization of fluorescent imprinted sensors.

Highly Sensitive Determination of 2,4,6-Trichlorophenol by Using a Novel SiO2@MIPIL Fluorescence Sensor with a Double Recognition Functional Monomer

A novel SiO₂@ MIPIL fluorescence sensor for the highly sensitive detection of 2,4,6-trichlorophenol was prepared by using surface molecularly imprinting technology with SiO₂ microspheres as carriers and 3,3'-(anthracene-9,10-diylbis(methylene))bis(1-vinyl-1H-imidazole-3-ium) chloride as a double recognition fluorescence functional monomer. The prepared molecularly imprinted polymer (SiO₂@MIPIL) was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, laser confocal microscopy, and nuclear magnetic resonance. Compared with the polymer obtained via bulk polymerization (MIPIL), the surface molecularly imprinted polymer (SiO₂@MIPIL) has a better linear range (0.1-50 nM), lower detection limit (89 pM), and shorter detection time (approximately 1.5 min). The fluorescence sensor also shows good specificity, high sensitivity, good stability, and reusability. Satisfactory results were obtained when using this sensor in industrial wastewater and spiked environmental water.