Cdse cds core shell3/28/2023 ![]() In addition, molecularly imprinted polymers (MIPs) are polymeric matrices that can be tailor-made to exhibit high selectivities towards target molecules and are commonly used in separation, sensors, and catalysts. Interestingly, a number of ratiometric fluorescence probes have exhibited significantly enhanced detection sensitivities compared to single emissive quantum dot probes and so have been widely used in the construction of fluorescent probes for the detection of environmental pollutants, such as Hg 2+, hydrogen sulfide, and sulfur dioxide. As such, strategies based on ratiometric fluorescence can be considered superior, as they eliminate the majority of these ambiguities through self-calibration of two or more different bands. However, such methods are generally based on the change in fluorescence intensity of a single luminophore, which is readily perturbed by a fluctuation in the excitation light intensity, the probe concentration, and the presence of fluorescence quenchers such as heavy metal ions and reactive oxygen species. Fluorescence methods for the determination of trace quantities of 4-NP are advantageous due to their simplicity, rapidness, and low cost. Quantum dots (QDs) are usually adopted as response signal in florescence monitoring and are also widely used in photoelectrochemical hydrogen generation, optoelectronic devices, and biological imaging due to their size/composition-dependent optical and electronic properties. To date, various analytical methods have been proposed for the determination of 4-NP in water, including chromatography, electrochemical detection, chemiluminescence detection, and fluorescence monitoring. Thus, the development of sensitive and selective methods for the detection of 4-NP is of particular importance. Indeed, the US Environmental Protection Agency (EPA) has listed 4-NP as a priority pollutant and has specified a maximum permitted limit of 60 ng/mL 4-NP in drinking water. In particular, 4-nitrophenol (4-NP) is one of the most toxic substituted nitrophenols, being both carcinogenic and genotoxic to humans and wildlife even at very low concentrations. Nitrophenols are among the most abundant environmental contaminants due to their widespread use in the production of herbicides, pesticides, synthetic dyes, and pharmaceuticals. Furthermore, the simplicity, reliability, high selectivity, and high sensitivity of the developed sensor demonstrate that the combination of MIPs and ratiometric fluorescence allows the preparation of excellent fluorescent sensors for the detection of trace or ultra-trace analytes. The probe was then applied in the detection of 4-NP and exhibited good linearity between 0.051 and 13.7 μg/mL, in addition to a low detection limit of 0.026 μg/mL. The morphology, chemical structure, and optical properties of the resulting molecularly imprinted dual-emission fluorescent probe were characterized by transmission electron microscopy and spectroscopic analysis. The nanohybrids were further modified by anchoring a molecularly imprinted polymer (MIP) layer on the ratiometric fluorescent sensor through a facile sol–gel polymerization method. This sensor was synthesized by linking organosilane-functionalized CDs to silica-coated CdSe quantum dots 2) via Si–O bonds. This sensor was functioned by the transfer of fluorescence resonance energy between photoluminescent carbon dots (CDs) and 4-NP. Thus, we herein fabricated a novel molecularly imprinted core-shell nanohybrid as a ratiometric fluorescent sensor for the highly sensitive and selective detection of 4-NP. 4-Nitrophenol (4-NP) is a priority pollutant in water and is both carcinogenic and genotoxic to humans and wildlife even at very low concentrations. ![]()
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