Preparation and Characterization of Hydrophilic Olaquindox Molecularly Imprinted Polymer in Aqueous Environment

Off-line magnetic Fe3O4@SiO2@MIPs-based solid phase dispersion extraction coupling with HPLC for the simultaneous determination of olaquindox and its metabolite in fish muscle and milk samples

An innovative core-shell magnetic molecularly imprinted polymers, Fe₃O₄@SiO₂@MIPs, was elaborately tailored for specific separation and enrichment of olaquindox (OLA) and its metabolic marker methyl-3-quinoxaline-2carboxylic acid (MQCA). Herein, benefiting from the combination of functionalized magnetic nanoparticles (Fe₃O₄@SiO₂) and MIPs, Fe₃O₄@SiO₂@MIPs not only possessed favorable magnetic properties and stability, avoiding tedious sample pretreatment process, but also demonstrated exceptional selective recognition ability and adsorption capacity, suppressing influence of coexisting interfering substances. Encouraged by prominent merits, Fe₃O₄@SiO₂@MIPs-based magnetic solid phase extraction with HPLC method was developed, realizing simultaneous measurement of OLA and MQCA. Under optimal conditions, excellent linear ranges of 0-100 μg/L with detection limit of 0.175-0.271 μg/L were obtained. The proposed method was finally utilized for determination of OLA and MQCA in fish muscle and milk samples with satisfactory recoveries (80.56-95.26%) and relative standard deviation below 8.1%, furnishing a reliable and sensitive strategy for enrichment and detection residual veterinary drugs in food samples.

Engineered Geomedia Kaolin Clay-Reduced Graphene Oxide-Polymer Composite for the Remediation of Olaquindox from Water

Globally, there is an upsurge in the use of unregulated veterinary pharmaceuticals with enhanced release into the environment, resulting in water pollution, which is difficult to remediate. To address this issue, we synthesized and characterized highly hydrophobic three-dimensional ordered engineered geomedia with multiple channels. Kaolin clay (K) was functionalized with either graphene oxide (GO) synthesized via Tour's method or reduced GO in situ with covalently linked methoxyether polyethylene glycol (GO-PEG) using a simple and easily scalable amidation reaction. This was done to enhance the adsorption of olaquindox, a veterinary antibiotic. The X-ray diffraction profile confirmed the grafting of GO and GO-PEG to kaolin. Morphological analysis revealed the architecture of thin films of GO/GO-PEG grafted on the kaolin surface with extensive porosity. Energy-dispersive X-ray mapping, infra-red spectra, and elemental analysis confirmed the successful synthesis of the engineered geomedia composite of K, GO/rGO, and PEG (KrGO-PEG). Due to multiple surface functional groups of polyamide and amido-carbonic groups on the KrGO-PEG composite, it was suitable for olaquindox adsorption. In batch sorption studies of 0.5XKrO-PEG, the effect of pH (2-10) was negligible but with fast equilibrium time (2-1440 min) at 30 min, while the kinetics and equilibrium data suited the pseudo-second order and Langmuir models, respectively. The maximum adsorption value obtained for the composite was 59.5 mg/g; the higher the GO content, the higher the adsorption. The sorption mechanism was majorly through hydrophobic and π-π interactions. Regenerated/reused adsorbents after 4 cycles had the same efficacy in remediating olaquindox from simulated/real water.

Rapidly photocatalytic mineralization of typical veterinary drugs with the SnO2/SnIn4S8 composite

Considering the high environmental risk, the remediation of veterinary drug pollutants aroused numerous concerning. In this paper, a novel photocatlyst, SnO₂/SnIn₄S₈, was fabricated by in situ precipitation and hydrothermal method and then employed to simulate photocatalytic degradation of olaquindox under visible light. The SEM, TEM, XRD, XPS and electrochemical results clearly showed that the n-type heterojunction between SnO₂ and SnIn₄S₈ was successfully constructed, which greatly reduce the recombination of the photogenic electron and holes, leading to the improvement of photocalytic performance and stability (recycled over 10 times). Besides, the SnO₂/SnIn₄S₈ composite also exhibited good ability to mineralize the olaquindox. Under the optimal condition (pH of 3, 1 g L^-1 of 30 wt% SnO₂/SnIn₄S₈ and 10 mg L^-1 of initial olaquindox concentration), the olaquindox could be fully and rapidly degraded in 25 min, and completely mineralized in 2 h (99.3 ± 1.7%). LC-QTOF-MS analysis evidently displayed 10 intermediates during the olaquindox degradation. In addition, with the attack of the reactive oxygen species (h⁺, •OH and •O₂^-), olaquindox could be effectively decomposed via deoxygenation, hydroxylation and carboxylation reactions. Importantly, compared to photodegradation, the photocatalytic process was an ideal way to eliminate the olaquindox form water because it could avoid the accumulation of toxic byproducts.

Recent advances in green reagents for molecularly imprinted polymers

Molecularly imprinted polymers (MIPs) are tailor-made materials with special binding sites.

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004-2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930-2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed.

Synthesis and evaluation of molecularly imprinted silica gel for 2-hydroxybenzoic Acid in aqueous solution

A molecularly imprinted silica gel sorbent for selective removal of 2-Hydroxybenzoic acid (2-HA) was prepared by a surface imprinting technique with a sol-gel process. The 2-HA molecularly imprinted silica gel (2-HA-MISG) sorbent was evaluated by various parameters, including the influence of pH, static, kinetic adsorption and selectivity experiments. The optimum adsorption capacity to the 2-HA appeared to be around pH 2 by the polymer. Morevoer, the imprinted sorbent displayed fast uptake kinetics, obtained within 20 min. The adsorption capacity of the 2-HA-MISG (76.2 mg g-1) was higher than that of the non-imprinted silica gel (NISG) (42.58 mg g-1). This indicates that the 2-HA-MISG offers a higher affinity for 2-HA than the NISG. The polymer displays good selectivity and exhibits good reusability. Experimental results show the potential of molecularly imprinted silica sorbent for selective removal of 2-HA.