Magnetic Molecularly Imprinted Polymers Research Articles

Development of a simple polymer-based sensor for detection of the Pirimicarb pesticide

In this study, a sensitive and selective fluorescent chemosensor was developed for the determination of pirimicarb pesticide by adopting the surface molecular imprinting approach. The magnetic molecularly imprinted polymer (MIP) nanocomposite was prepared using pirimicarb as the template molecule, CuFe2O4 nanoparticles, and graphene quantum dots as a fluorophore (MIP-CuFe2O4/GQDs). It was then characterized using X-ray diffraction (XRD) technique, Fourier transforms infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), and transmission electron microscopy (TEM). The response surface methodology (RSM) was also employed to optimize and estimate the effective parameters of pirimicarb adsorption by this polymer. According to the experimental results, the average particle size and imprinting factor (IF) of this polymer are 53.61 nm and 2.48, respectively. Moreover, this polymer has an excellent ability to adsorb pirimicarb with a removal percentage of 99.92 at pH = 7.54, initial pirimicarb concentration = 10.17 mg/L, polymer dosage = 840 mg/L, and contact time = 6.15 min. The detection of pirimicarb was performed by fluorescence spectroscopy at a concentration range of 0–50 mg/L, and a sensitivity of 15.808 a.u/mg and a limit of detection of 1.79 mg/L were obtained. Real samples with RSD less than 2 were measured using this chemosensor. Besides, the proposed chemosensor demonstrated remarkable selectivity by checking some other insecticides with similar and different molecular structures to pirimicarb, such as diazinon, deltamethrin, and chlorpyrifos.

Magnetic molecularly imprinted polymers are used to selectively extract cephalosporins from milk samples and analyze by LC-MS/MS

Cephalosporins were extracted from milk samples by using magnetic molecularly imprinted polymers (MMIP). To characterize the physical properties of MMIP, an experiment was conducted involving both static and dynamic adsorption. Samples were analyzed with LC-MS/MS to identify cephalosporin residues. The quantitative technique employed was the use of an isotope as an internal standard. Analysis was conducted using an Ascentis C8 column with a mobile phase consisting of a 0.1% aqueous solution of formic acid and acetonitrile. The determination coefficients varied between 0.9945 and 0.9995, as indicated by the linear equations. Cephalosporins exhibited a diverse spectrum of recovery rates, varying between 80.7% and 118.3%, accompanied by a range of relative standard deviations spanning from 3.8% to 13.5%. The detection limits for 9 kinds of cephalosporins in milk samples varied from 1 μg kg−1 to 20 μg kg−1, while the quantification limits ranged from 3 μg kg−1 to 60 μg kg−1. The successful implementation of the validated technique has been applied to detect 9 different kinds of cephalosporins in real milk products.

Molecularly Imprinted Drug Carrier for Lamotrigine—Design, Synthesis, and Characterization of Physicochemical Parameters

This study presents the initial attempt at introducing a magnetic molecularly imprinted polymer (MIP) designed specifically for lamotrigine with the purpose of functioning as a drug carrier. First, the composition of the magnetic polymer underwent optimization based on bulk polymer adsorption studies and theoretical analyses. The magnetic MIP was synthesized from itaconic acid and ethylene glycol dimethacrylate exhibiting a drug loading capacity of 3.4 ± 0.9 μg g−1. Structural characterization was performed using powder X-ray diffraction analysis, vibrating sample magnetometry, and Fourier transform infrared spectroscopy. The resulting MIP demonstrated controlled drug released characteristics without a burst effect in the phospahe buffer saline at pH 5 and 8. These findings hold promise for the potential nasal administration of lamotrigine in future applications.

Selective adsorption of zearalenone by a novel magnetic molecularly imprinted carbon nanomaterial.

In this paper, the objective is to immobilize molecularly imprinted polymers (MIPs) onto the surface of magnetic carbon nanoparticles (Fe3O4@SiO2@C) to develop an effective method for the adsorption of zearalenone (ZEN). The prepared products were characterized by FT-IR, SEM, TEM, XRD, VSM, TGA, and BET. The content of zearalenone in corn samples was monitored by HPLC. The results indicate that the particle size of magnetic molecularly imprinted polymers (MMIPs) is approximately 200nm. The adsorption mechanism of MMIPs was confirmed by static adsorption and dynamic adsorption experiments. The maximum adsorption capacity was 1.56mg/g, and the adsorption equilibrium was reached within 50min. The scatchard model showed that MMIPs had two binding sites, a high-affinity binding site and a low-affinity site. Kinetic second-order fitting indicates that MMIPs are mainly through chemisorption. In the actual sample application, the limit of detection (LOD) and limit of quantitation (LOQ) were 0.3mg/L and 0.9mg/L, respectively. The recovery of corn with the standard addition of ZEN was 73.6-88.1%, and the relative standard deviation (RSD) was 2.86-5.63%. The results demonstrated that MMIPs possess the advantages of straightforward operation, high precision, and cost-effectiveness, rendering them suitable for rapid ZEN detection.

Magnetic molecularly imprinted polymers using ternary deep eutectic solvent as novel functional monomer for hydroxytyrosol separation

In this work, magnetic molecularly imprinted polymers (MIPs) for specific recognition of Hydroxytyrosol (HT) were designed by vinyl-modified magnetic particles (Fe3O4@SiO2@VTEOs) as carrier, ternary deep eutectic solvent (DES) as functional monomer, while ethylene glycol dimethacrylate (EGDMA) as crosslinker. The optimum amount of DES was obtained by adsorption experiments (molar ratio, caffeic acid: choline chloride: formic acid = 1:6:3) which were 140 μL in total. Under the optimized amount of DES, the maximum adsorption capacity of the MIPs particles was 42.43 mg g−1, which was superior to non-imprinted polymer (4.64 mg g−1) and the imprinting factor (IF) is 9.10. Syringin and Oleuropicrin were used as two reference molecules to test the selectivity of the DES-MIPs particles. The adsorption capacity of HT was 40.11 mg g−1. Three repeated experiments show that the polymer has high stability and repeatability (RSD = 5.50).

Preparation of surface molecularly imprinted polymers with Fe3O4/ZIF-8 as carrier for detection of Dimethoate in cabbage

In this study, molecularly imprinted polymers (MIPs) were prepared for the specific recognition of organophosphorus pesticides and a rapid, efficient and simple method was established for the detection of dimethoate (DIT) in food samples. Fe3O4 magnetic nanoparticles were synthesized by co-precipitation, and Fe3O4/ZIF-8 complexes were prepared by a modified in-situ polymerization method, and then magnetic molecularly imprinted polymers (MMIPs) were prepared and synthetic route was optimized by applying density functional theory (DFT). The morphological characterization showed that the MMIPs were coarse porous spheres with an average particle size of 50 nm. The synthesized materials are highly selective for the organophosphorus pesticide dimethoate with an adsorption capacity of 461.50 mg·g−1 and are effective resistance to matrix effects. A novel method for the determination of DIT in cabbage was developed using the prepared MMIPs in combination with HPLC. The practical results showed that the method can meet the requirements for the determination of DIT in cabbage with recoveries of 85.6-121.1% and detection limits of 0.033 μg·kg−1.

The Application of Pipette-Tip and Magnetic Dummy-Template Molecularly Imprinted Solid-Phase Extraction Coupled with High-Performance Liquid Chromatography with Diode Array and Spectrofluorimetric Detection for the Determination of Coumarins in Cosmetic Samples

In this study, adsorbents based on molecularly imprinted polymers (MIPs) in two solid-phase extraction application forms, pipette tip and magnetic extraction, were used for the selective extraction of coumarins. The pipette-tip solid-phase extraction reduced solvent volumes; the magnetic MIP extraction was simple and effective for phase separation. Parameters affecting extraction, such as the amount of adsorbent, type of washing solvent, volume of the elution solvent, and extraction times for magnetic extraction, were optimized. The MIP-based adsorbents displayed high selectivity and extraction efficiency, resulting in recoveries ranging from 70.3 to 102.0% (RSD % less than 5.5%) for five coumarins under study, 6,7-dihydroxycoumarin-6-β-D-glucoside, coumarin, 7-methoxycoumarin, 6-methylcoumarin, and dicoumarol. The extracts were analyzed by high-performance liquid chromatography with diode array (DAD) and fluorescence (FLD) detectors, reaching limits of quantification of 0.5 and 0.9 µg·mL−1 for coumarin and dicoumarol detected by DAD and 0.001–0.012 µg·mL−1 for the other prohibited simple coumarins when used as a fragrance (detected by FLD). The proposed method was validated and its applicability was shown for the analysis of cosmetic samples like shower gel and perfume.

Selective Extraction and Determination of Hydrocortisone and Dexamethasone in Skincare Cosmetics: Analytical Interpretation Using Statistical Physics Formalism

Molecularly imprinted polymers (MIPs), as magnetic extraction adsorbents, are used for the selective, rapid determination and extraction of dexamethasone and hydrocortisone in skincare products. Therefore, in this paper, magnetic molecularly imprinted polymers (MMIPs) and magnetic non-molecularly imprinted polymers (MNIPs) were utilized as adsorbents to describe the adsorption phenomena of dexamethasone and hydrocortisone. This interpretation, based on a statistical physics theory, applies the multilayer model with saturation to comprehend the adsorption of the drugs. Results obtained via numerical simulation revealed that dexamethasone and hydrocortisone adsorption happens via a non-parallel orientation on the surfaces of MMIPs and MNIPs, and they also showed that the adsorption amount of the MMIPs for the template molecule was notably greater than that of the MNIPs at the same initial concentration. The adsorption energy values retrieved from the data analysis ranged between 7.65 and 15.77 kJ/mol, indicating that the extraction and determination of dexamethasone and hydrocortisone is a physisorption process. Moreover, the distribution of a site’s energy was calculated to confirm the physical nature of the interactions between adsorbate/adsorbent and the heterogeneity of the surfaces of the MMIPs and MNIPs. Finally, the thermodynamic interpretation confirmed the exothermicity and spontaneous nature of the adsorption of these drugs on the tested adsorbents.

Magnetic Molecularly Imprinted Polymers for Selective Extraction of Aflatoxins from Feeds.

Magnetic molecularly imprinted polymers (MMIPs) have fused molecular imprinting technology with magnetic separation technology, emerging as an innovative material capable of recognizing specific molecules and efficiently separating target substances. Their application to the extraction and purification of mycotoxins has great potential, due to the toxicity and economic impact of these contaminants. In this work, MMIP has been proposed as a sample treatment for the determination of main four aflatoxins (B1, B2, G1 and G2) in pig feed. The MMIP was formed through the integration of magnetic material (Fe3O4) with commercial molecularly imprinted polymers, avoiding the synthesis step and, therefore, simplifying the process. The analyses were carried out by high-performance liquid chromatography with fluorescence detection and the method was validated and limits of quantification (LOQs) between 0.09 and 0.47 ng/g were obtained, below the allowed or recommended levels by the European Union. Repeatability and intermediate precision showed relative standard deviations lower than 10% in all cases and trueness ranged from 92 to 111%. Finally, the proposed method was applied to 31 real pig feed samples, detecting aflatoxins with concentrations between 0.2 and 3.2 ng/g.

Synthesis of Molecularly Imprinted Polymers with Magnetite Cores for Ibuprofen Adsorption

Ibuprofen (IBP) is a pollutant that is widely found in aquatic environments due to pharmaceutical waste and the metabolic results of humans who consume the drug. These compounds can cause damage to aquatic ecosystems, genotoxicity, and aquatic toxicity and are harmful to human health. This study aims to selectively adsorb IBP using magnetic molecularly imprinted polymers (MMIPs) synthesized from ibuprofen (IBP) as a template molecule, methacrylic acid (MAA) as a functional monomer, and divinylbenzene (DVB) as a crosslinker with a mole ratio of 1:4:20 in acetonitrile porogen solvent using a bulk polymerization method. Fe3O4 nanoparticles and MMIPs were characterized using X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR), and Scanning Electron Microscope (SEM). IBP adsorption reached optimum conditions at pH 3 with a contact time of 90 minutes and a mass of 25 mg of adsorbent. The adsorption performance of MMIPs for IBP was evaluated by adsorption isotherms and adsorption kinetics. Adsorption of IBP by MMIPs followed the Langmuir adsorption isotherm model with an adsorption capacity of 227.24 mg/g. Kinetic studies showed that the adsorption process followed a pseudo-second-order adsorption kinetic model. MMIPs can adsorb IBP selectively even in the presence of interfering compounds, are easily separated from the solution, and can be used repeatedly with good adsorption ability. Hence, it is efficient and promising for removing IBP from aqueous media.

Synthesis of magnetic bifunctional monomer molecularly imprinted polymers for highly selective separation of paclitaxel from Taxus cuspidata

Paclitaxel (PTX), an active anticancer compound derived from Taxus cuspidata, possesses considerable economic value. Given the abundance of structural analogs, the selective separation of PTX from T. cuspidata presents a formidable challenge. In this study, the bifunctional monomers magnetic molecular imprinted polymers (MMIPs) with multiple active sites were synthesized using Fe3O4 as the magnetic carrier, PTX as the template, 4-vinylpyridine (4-VP) and methacrylic acid (MAA) as the first-stage and the second-stage pre-assembly functional monomer, respectively. The results indicated that MMIPs exhibited excellent magnetic recovery capability and high adsorption capacity for PTX. Furthermore, the adsorption behaviors were more consistent with Langmuir isotherm model and pseudo-second-order kinetic model. The MMIPs possessed significantly higher selectivity for PTX than five structural analogs (Docetaxel, Baccatin III, 10-Deacetylbaccatin III, and Glucose) and recyclability for up to six cycles. Additionally, the adsorption mechanism analysis indicated that the excellent performance of MMIPs primarily arises from the multiple active binding sites involving hydrogen bonding and π-π stacking. Finally, MMIPs were used for PTX recognition and separation in T. cuspidata extracts. This study provides an efficient method and valuable theoretical basis for the highly selective separation of PTX from T. cuspidata.

Facile and fast fabrication of magnetic molecularly imprinted polymer for extraction of carbamazepine from environmental samples and fish tissues followed by UHPLC-MS/MS detection

A rapid synthesis of carbamazepine (CBZ) magnetic molecularly imprinted polymer (MMIP) was proposed based on reflux precipitation polymerization method. The synthesis time for the formation of MIP coating on MMIP was shortened to less than 4 h. The characterization of MMIP demonstrates the successful synthesis of the imprinted layer. The adsorption selectivity of MMIP was systematically evaluated and showed fast selective recognition for CBZ. The MMIP based magnetic solid-phase extraction (MSPE) combined with UHPLC-MS/MS was developed, and its feasibility was validated in four complex matrices of environmental water, sediment, fish muscle and liver. It was successfully applied for the analysis of environmental water, sediment, and different fish tissues. Four environmental water samples from different sampling sites were found to contain CBZ at concentrations < LOD or LOQ, while the sediment samples collected at the same location did not contain CBZ. Two out of three wild snakeheads were found to contain CBZ, and the liver showed the highest residue. The study of drug exposed snakeheads indicate CBZ tends to accumulate in liver, followed by brain, heart and kidneys, and finally muscle and gills. The proposed method displays high potential for analyzing CBZ in complex environmental and biological samples.

Dispersive micro solid phase extraction of glibenclamide from plasma, urine, and wastewater using a magnetic molecularly imprinted polymer followed by its determination by a high-performance liquid chromatography-photodiode array detector.

The present study describes the development of a simple and selective analytical method for dispersive micro solid phase extraction and determination of glibenclamide (GLB) using magnetic molecularly imprinted polymer (MMIP) as a sorbent. MMIP was fabricated by the non-covalent method on the surface of silicated Fe3O4 and had a high affinity for glibenclamide; dual monomers, itaconic acid and allylamine, were used for this. Polymerization was achieved by the precipitation method in the presence of glibenclamide as the template and ethylene glycol dimethacrylate as the cross-linker. The morphology and structural properties of the MMIP were characterized by different analytical methods. To achieve maximum extraction efficiency, influencing parameters were optimized. The linearity range was 1-2000 and 12-2000 μg L-1 by high-performance liquid chromatography-photodiode array detector (HPLC-PDA) and UV-vis spectroscopy, respectively. The detection and quantification limits with UV-vis and HPLC-PDA analyses were 4 and 12 μg L-1 and 0.3 and 1 μg L-1, respectively. Under optimized conditions, recovery of glibenclamide spiked in plasma, human urine, and wastewater was between 89.4 and 102.9% at the concentration levels of 25, 250, and 500 μg L-1; relative standard deviations were below 3.7% by HPLC-PDA. The developed method has a favorable pre-concentration factor of 140.0. Equilibrium data and sorption isotherms fitted well with the Langmuir model. A maximum sorption capacity of 24.260 mg g-1 was acquired based on the Langmuir model. The synthesized sorbent with high selectivity was used to separate GLB from complex biological systems and wastewater before measurement with UV-vis or HPLC-PDA.

Molecularly imprinted polymer-based SERS sensing of transferrin in human serum.

Specific detection of glycoproteins such as transferrin (TRF) related to neurological diseases, hepatoma and other diseases always plays an important role in the field of disease diagnosis. We designed an antibody-free immunoassay sensing method based on molecularly imprinted polymers (MIPs) formed by the polymerization of multiple functional monomers for the sensitive and selective detection of TRF in human serum. In the sandwich surface-enhanced Raman spectroscopy (SERS) sensor, the TRF-oriented magnetic MIP nanoparticles (Fe3O4@SiO2-MIPs) served as capture units to specifically recognize TRF and 4-mercaptophenylboronic acid-functionalized gold nanorods (MPBA-Au NRs) served as SERS probes to label the targets. In order to achieve stronger interaction between the recognition cavities of the prepared MIPs and the different amino acid fragments that make up TRF, Fe3O4@SiO2-MIPs were obtained through polycondensation reactions between more silylating reagents, enhancing the specific recognition of the entire TRF protein and achieving high IF. This sensing method exhibited a good linear response to TRF within the TRF concentration range of 0.01 ng mL-1 to 1 mg mL-1 (R2 = 0.9974), and the LOD was 0.00407 ng mL-1 (S/N = 3). The good stability, reproducibility and specificity of the resulting MIP based SERS sensor were demonstrated. The determination of TRF in human serum confirmed the feasibility of the method in practical applications.

Selective extraction of maleic hydrazide in foods using magnetic molecularly imprinted polymers and colorimetric detection via smartphone

Maleic hydrazide (MH) is a plant growth regulator, herbicide, and sprout inhibitor used to improve the growth and quality of certain vegetables and fruits, unfortunately, MH has genotoxic and carcinogenic effects; thus, MH residues in food need to be analyzed. Herein, magnetic molecularly imprinted polymers (MagMIP) were synthesized by radical polymerization in just 30 min using a microwave for rapid and selective extraction of MH. The colorimetric detection of MH using the immobilized Folin Ciocalteau's reagent (FCR) on 96-well microplate via smartphone sensor exhibits useful sensitivity for MH with a limit of detection (LOD = 0.6 ppm) which is far lower than the maximum residue limits (higher than 5 ppm). The immobilized FCR was stored dry at two different storage conditions at +4 °C and room temperature without losing its performance over six months. The coupling MagMIP-extraction/clean-up and smartphone determination were tested towards food samples (i.e., potatoes, and carrots), obtaining good recovery (79–96 %), high repeatability (RSD 4.5 %; n = 10), and high selectivity for MH determination.

Development of magnetic molecularly imprinted polymers for selective extraction of Benzoxazolinone-type alkaloids from acanthus plants

Benzoxazolinone-type alkaloids found in Acanthus ebracteatus and Acanthus ilicifolius Linnaeus possess various beneficial properties, such as antileishmanial, antipyretic, analgesic, antibacterial, and antioxidant effects. In this study, we employed a surface imprinting technique on nanomaterials. We utilized functionalized Fe3O4@SiO2NH2 as a scaffold, with 2-benzoxazolinone and 2H-1,4-benzoxazin-3(4H)-one serving as dual templates, methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a crosslinker, and 2,2-azodiisobutyric nitrile (AIBN) as the initiator. Prior to polymerization, we screened functional monomers using ultraviolet (UV) spectroscopy. The resulting magnetic surface molecular imprinting polymer (Fe3O4@SiO2@MIP) was thoroughly characterized using Fourier transform infrared spectrometry (FT-IR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). We also conducted assessments of its adsorption isotherms, dynamics, and selective binding capabilities. Our findings indicate that the MIPs exhibited exceptional selective recognition performance. Through meticulous screening and optimization of extraction and separation conditions, we established an LC‒MS/MS method based on magnetic solid-phase extraction technology. The method exhibited a recovery range of 78.80–106.99 % (RSD, 0.46–3.31 %) for 2-benzoxazolinone, with a limit of detection (LOD) and limit of quantification (LOQ) of 2.85 and 9.00 μg L−1, respectively. For 2H-1,4-benzoxazin-3(4H)-one, the method yielded a recovery range of 84.75–103.53 % (RSD, 0.07–5.96 %), with an LOD and LOQ of 3.60 and 12.60 μg L−1, respectively, in real samples. The resulting Fe3O4@SiO2@MIP demonstrated a high capacity for class-specific adsorption.

Synthesis and Properties of Cefixime Core-Shell Magnetic Nano-Molecularly Imprinted Materials.

Novel core-shell magnetic molecularly imprinted polymers (MMIPs) were synthesized using the sol-gel method for the adsorption of cefixime (CFX). Fe3O4@SiO2 is the core, and molecularly imprinted polymers (MIPs) are the shell, which can selectively interact with CFX. The preparation conditions, adsorption kinetics, adsorption isotherms, selective adsorption ability, and reutilization performance of the MMIPs were investigated. The adsorption capacity of MMIPs for CFX was 111.38 mg/g, which was about 3.5 times that of MNIPs. The adsorption equilibrium time was 180 min. The dynamic adsorption experiments showed that the adsorption process of MMIPs to CFX conformed to the pseudo-second-order model. Through static adsorption study, the Scatchard analysis showed that MMIPs had two types of binding sites-the high-affinity binding sites and the low-affinity binding sites-while the Langmuir model fit the adsorption isotherms well (R2 = 0.9962). Cefepime and ceftiofur were selected as the structural analogs of CFX for selective adsorption studies; the adsorption of CFX by MMIPs was higher than that of other structural analogs; and the imprinting factors of CFX, cefepime, and ceftiofur were 3.5, 1.7, and 1.4, respectively. Furthermore, the MMIPs also showed excellent reusable performance.

A sensitive Raman spectroscopy sensor for determination cardiac troponin I based on proteolytic peptide magnetic imprinting technology

This paper proposes a selective strategy for quantitative detecting cardiac troponin I (cTnI) in clinical serum samples by using Raman spectroscopy combined with magnetic molecularly imprinted polymers (MMIPs). The signature peptide was selected as a template for molecular imprinting due to its chemical stability and small molecular mass. MMIPs were synthetized with the signature peptide as template and methylacrylic acid as monomer in presence of vinyl-modified magnetic particles. MMIPs with high magnetic character and adsorption properties were able to be stained by Coomassie Brilliant Blue G-250 after the target template was specifically captured, which showing a characteristic absorption peak at Raman shift 1610 cm−1. The Raman signal intensity at 1610 cm−1 showed a linear relationship in the 0.01 to 100 ng·mL−1 concentration range. The recovery of cTnI in serum were 92.7–111.2 % with relative standard deviation in the range of 2.51 % to 8.52 %. This paper has important practical application for preliminary rapid detection of cTnI in clinical serum samples.

Optimal preparation of pyrene magnetic molecularly imprinted polymers by simulation calculation and study of its adsorption properties

The combination of magnetic molecular imprinting technology and simulation calculation has gained significant attention in the field of sample pretreatment due to its ability to reduce solvent consumption during the preparation process. However, traditional simulation methods have limitations in visualizing the π-π stack mechanism between target molecules and functional monomers. This study introduces a new method called interactive regional indicators, which can effectively select suitable functional monomers for the preparation of pyrene magnetic molecular imprinting polymers (PMs) by visualizing weak interactions. The results showed that PMs had higher adsorption capacity faster adsorption rate, and good selectivity, stability, and reproducibility. PMs were applied to the adsorption of tap water and vegetable oil adsorption and its structural analogs. The results show that the LODs (S/N = 3) of PMs in water and canola oil samples are 0.82 × 10−5-4.1 × 10−5 mg/L and 0.576 × 10−3-4.347 × 10−3 mg/L, respectively, with high accuracy and precision. This method can be used for the pretreatment of pyrene in many substrates. It verifies the accuracy of theoretical calculation and provides some data support for theoretical calculation combined with experimental research.

Development of molecularly imprinted polymers and its magnetic version for the extraction of fluoroquinolones from milk

The aim of the present study is to develop selective extracting materials applicable to a diversity of fluoroquinolones. A series of Molecularly Imprinted Materials (MIPs) were prepared in order to choose the nature of the monomer and that of the porogen together with its ratio with the cross-linker. A non-regulated quinolone, Levofloxacin, was used as a template to avoid false positive results in its application. The resulting MIPs were evaluated in MISPE experiments for Enrofloxacin. The polymer prepared using methyl acrylate (MA) as a monomer and MeOH/CHCl3 (1:1, v/v) as a porogen provided the desired selectivity. Concretely, 100 μL (1.1 mmol) of MA as a monomer, 1.30 mL (9.8 mmol) of EGDMA (ethyleneglycol dimethacrylate) as a cross-linker, 31 mg (0.19 mmol) of AIBN (2,2′-azobis(2-methylpropionitrile)) as an initiator, were mixed with 85 mg (0.24 mmol) of levofloxacin as a template and 4 mL of MeOH/CHCl3 (1:1, v/v) as a porogen.The obtained optimized composition was upgraded to magnetic molecularly imprinted polymers (MMIPs) to be used as a dispersive-SPE extracting materials in the analysis of fluoroquinolones in milk. The selectivity of the resulting material for several fluoroquinolones (enrofloxacin, ciprofloxacin, sarafloxacin and norfloxacin) was studied. Finally, the MMIP was tested against real quinolone positive milk samples to evaluate its applicability.