Magnetic Ion-imprinted Polymer Research Articles

Fiber optic cadmium ion sensors based on functionalization of a magnetic ion-imprinted polymer.

Cadmium poisoning is a chronic accumulation process, and long-term drinking of even low cadmium content water will cause kidney damage, so an ultra-low detection limit is particularly important. However, at the present stage, the traditional detection method cannot reach a sufficiently low detection limit, the response time is too long, and the cost of detection is very high, so that real-time measurement cannot be realized. Therefore, the traditional cadmium ion detection method has a slow response and an insufficient detection limit. This paper presents a fiber optic cadmium ion sensor functionalized based on an Fe3O4@SiO2@CS magnetic ion imprinting polymer (M-IIP). The sensor is based on the coupling characteristics of the optical microfiber coupler (OMC) cone region to achieve a highly sensitive response to the change in the cadmium ion concentration. M-IIP materials were prepared by surface imprinting polymerization to achieve low cross-sensitivity and thus improve the detection limit of the sensor. The results show that the developed fiber sensor has high specificity and a rapid response to cadmium ions. The experimental limit of detection (LOD) reached 0.051 nM within 0-1 μM with a response time of less than 50 s. Moreover, the proposed fiber cadmium ion sensor exhibits excellent performance in terms of sensitivity, stability, repeatability and biocompatibility.

Synthesis of ionically imprinted Poly(Alylthiourea) in the presence of 1-(2-Pyridylazo)-2-Napthol (PAN) for preconcentration in magnetic dispersive solid phase of nickel ions in water and food samples

In the present study, a magnetic ion-imprinted polymer based on n-allylthiourea in the presence of 1-(2-pyridylazo)-2-naphthol (MIIP-PAN) was synthesized, characterized, and applied in the preconcentration of nickel ions by dispersive magnetic solid phase extraction (DMSPE) with FAAS detection. For comparison, non-imprinted polymer (MNIP-PAN) and imprinted polymer without PAN were synthesized. The characterization of the polymers was performed by FT-IR, DRX, TEM, TGA, VSM, and BET. Selectivity studies were performed comparing the competitive adsorption of Ni2+ with other cations on MIIP-PAN and MNIP-PAN, achieving higher relative selectivity coefficients for MIIP-PAN than for MNIP-PAN and NIP. Under optimized conditions, the method provided a preconcentration factor of 76.70, detection limit of 0.25 µg/L and intra-day (2.06 – 2.33 %) and inter-day (1.82 – 4.90 %) precision. The developed method was applied to samples of water, teas, and chocolate powder, and its precision was evaluated through tests of recovery and analysis of certified materials.

Construction of 1, 10-phenanthroline functionalized magnetic starch as a lead (II) tagged surface imprinted biopolymer for highly selective targeting of toxic lead ions

In this research 1, 10 - phenanthroline functionalized CaFe2O4 - starch was employed as a magnetic ion-imprinted polymer (IIP) for highly selective targeting toxic Pb2+ ions from aqueous media. VSM analysis revealed that the sorbent has magnetic saturation of 10 emu g−1 which is appropriate for magnetic separation. Moreover, TEM analysis confirmed that the adsorbent is composed of particles with a mean diameter of 10 nm. According to XPS analysis, lead coordination with phenanthroline is the main adsorption mechanism that is along with electrostatic interaction. A maximum adsorption capacity of 120 mg g−1 was obtained within 10 min at a pH of 6 and an adsorbent dosage of 20 mg. Kinetic and isotherm studies showed that lead adsorption followed the pseudo-second–order and Freundlich models, respectively. The selectivity coefficient of Pb (II) relative to Cu(II), Co(II), Ni(II), Zn(II), Mn(II), and Cd(II) was 4.7, 14, 20, 36, 13 and 25, respectively. Moreover, the IIP represents the imprinting factor of 1.32. The sorbent showed good regeneration after five cycles of the sorption/desorption process with an efficiency of >93 %. Finally represented IIP was used for lead preconcentration from various matrices i.e., water, vegetable, and fish samples.

A simple and cost-effective synthesis route using itaconic acid to prepare a magnetic ion-imprinted polymer for preconcentration of Pb (II) from aqueous media

A new Pb (II) magnetic ion-imprinted polymer (Pb-MIIP) was successfully investigated for the selective extraction of Pb (II) from an aqueous solution. MIIP nanostructures were developed using itaconic acid-coated iron oxide nanoparticles (Fe3O4@ITA) as a novel magnetic core, ITA as a functional monomer and chelating agent, ethylene glycol dimethacrylate (EGDMA) as a cross-linker, and 2,2-azobisisobutyronitrile (AIBN) as an initiator. The triple application of ITA in the synthesis and reduction of the number of compounds in the preparation of the MIIP, in addition to being economical, reduces the possibility of side reactions. The synthesized products were followed and confirmed in each step by instrumental and microscopic methods. The limit of detection of the Pb (II)-MIIP method was 0.21 μg L−1. Under the optimal conditions, the recovery (R%) was >90% with a relative standard deviation (RSD%) of <4.9%. The synthesized MIIP was reusable and successfully used to extract Pb (II) from tap water samples.

Synthesis, characterization, and performance comparison of boron using adsorbents based on N-methyl-D-glucosamine

Using N-methyl-D-glucosamine (NMDG) as the functional monomer, glycidyl methacrylate (GMA) as the connecting monomer, functionalized Fe3O4 nano-particles (NPs) as the support, three adsorbents were prepared including direct polymer GMA-NMDG, magnetic GMA-NMDG polymer (MGN), and boron magnetic ion-imprinted polymer (BMIIP). Based upon the optimization of synthesis conditions, the prepared adsorbents and intermediate products were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscope, energy dispersive spectroscopy, X-ray diffraction, vibrating sample magnetometer, and Brunauer–Emmett–Teller to investigate the synthesis process, the morphological structure and the functional properties of the materials. The optimum performances of GMA-NMDG, MGN and BMIIP were obtained in the initial neutral solution (pH of 6.5). Moreover, GMA-NMDG and MGN reached the maximum adsorption capacity at 120 min, whereas BMIIP reached adsorption saturation at 60 min. The pseudo-second-order kinetic model was more suitable for the adsorption of boron using the adsorbents. The maximum adsorption capacity of GMA-NMDG was found to be 43.4 mg·g−1, while those of MGN and BMIIP were 32.5 and 28.3 mg·g−1, respectively. The Langmuir isotherm model was more appropriate to describe the adsorption process. The adsorbents maintained satisfactory adsorption performance within a certain temperature range. Competing ions had little effect on the adsorption of boron, and would be adsorbed simultaneously, due to which, the effect of co-adsorption can be considered. The adsorption capacity of GMA-NMDG was high, while the adsorption selectivity of BMIIP was much better. Furthermore, BMIIP showed good adsorption after five cycles of adsorption and desorption. The comparison of adsorbents showed that GMA-NMDG had the highest adsorption capacity and was suitable for co-adsorption. MGN had a high adsorption capacity, good comprehensive performance and magnetic properties. BMIIP had better adsorption rate, adsorption selectivity and recyclability. Through the optimization of synthesis conditions, the adsorption capacity of the traditional monomer NMDG polymer was increased, and the magnetism was given to facilitate rapid recovery. Combined with the ion imprinting technology, it showed higher boron adsorption selectivity in the presence of competitive ions.

Histidine-mediated dendritic mesoporous magnetic ion-imprinted polymer toward effective and recoverable cadmium removal

In this study, a magnetic dendritic mesoporous silica nanoparticle material (MDMS@MAH-Cd-IIP) was prepared via surface ion-imprinted technique for selective removal of Cd(Ⅱ) from aqueous solution. The material was based on an ion-imprinted copolymers of 4-vinyl pyridine (4-VP) and N-methacryloyl-L-histidine (MAH), a synthesized ligand monomer to complex with cadmium ions as ion recognition layer. The obtained polymer was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and magnetic measurement system. The adsorption experiments exhibited MDMS@MAH-Cd-IIP showed fast (within 35 min) and selective capture of Cd(Ⅱ) with maximum uptake capacity of 21.04 mg g−1. The adsorption process followed pseudo-second order kinetic and Langmuir adsorption isotherm models, indicating monolayer chemisorption on homogeneous sites was the rate-limiting step. Meanwhile, the MDMS@MAH-Cd-IIP also showed a specificity recognition ability for Cd(Ⅱ) using analogues Co(Ⅱ), Pb(Ⅱ), Zn(Ⅱ) and Ni(Ⅱ) as interference. Moreover, the MDMS@MAH-Cd-IIP based magnetic SPE can extract approximately 90.0–102.0% of Cd (Ⅱ) in real water samples with a RSD of 3.34–8.23%, which indicated the polymer had the high stability and reproducibility and presented itself a promising material for the Cd(Ⅱ) adsorption and detection from aqueous solution.

Fabrication of a novel magnetic rubidium ion-imprinted polymer for selective separation

A novel magnetic ion-imprinted polymer (MIIP) for Rb+ was synthesized by combining the surface imprinting technology with the magnetic separation technology.

Novel Magnetic Ion-imprinted Polymer Extraction of Trace Ce(III) in Environmental and Mineral Samples and Determination by ICP-MS

Novel Magnetic Ion-imprinted Polymer Extraction of Trace Ce(III) in Environmental and Mineral Samples and Determination by ICP-MS

Utilizing a Nanocomposite Based on Ion-Imprinted Polydopamine-Coated Magnetic Graphene Oxide for Extraction of Cd(II) and Ni(II) from Water Samples

In this study, a new magnetic ion-imprinted polymer was prepared as a nanosorbent for selective extraction and pre-concentration of low levels of Cd(II) and Ni(II) prior to determination by flame atomic absorption spectrometry. The sorbent material consists of graphene oxide as a carrier, Fe3O4 nanoparticles as magnetic components immobilized on the surface of the carrier and polydopamine as a metal ion-imprinted polymer which is uniformly coated on the surface of the magnetic graphene oxide sheet layer. Several factors affecting the extraction of the analytes were studied and optimized. In the optimum conditions, the calibration graphs were linear in the ranges of 0.1–18 and 0.1–20 ng/mL for Cd(II) and Ni(II), respectively. The limits of detection (3sb/m) for Cd(II) and Ni(II) were 25 and 60 pg/mL, respectively. The accuracy of the method was confirmed by successful analyzing the certified reference material NIST SRM 1643e. The method can be used for the pre-concentration and determination of Ni(II) and Cd(II) in water samples.

Magnetic ion-imprinted polymer based on mesoporous silica for selective removal of Co(II) from radioactive wastewater

ABSTRACT A magnetically separable Co(II)-imprinted polymer based on mesoporous silica (mag@silica-CIP) was synthesized for use as an adsorbent for the selective removal of Co(II). The optimal pH for Co(II) adsorption was found to be 5. Increasing the amount of the Co(II)-imprinted polymer layer on the surface of mag@silica led to an increase in the maximum adsorption capacity for Co(II). The mag@silica-CIP selectively adsorbed Co(II) even in the presence of competing species such as Fe(II), Ni(II), and Mn(II) ions. Thermodynamic experiments revealed that the adsorption of Co(II) by mag@silica-CIP is an endothermic and spontaneous process.

Preparation of a new magnetic ion-imprinted polymer and optimization using Box-Behnken design for selective removal and determination of Cu(II) in food and wastewater samples

A new magnetic Cu(II) IIP (Fe3O4@IIP-IDC) is synthesized by polymerization of Imidazole-4,5-dicarboxylic acid functionalized Allyl chloride, and significant improvement of its performance has been compared. SPE parameters were optimized using Box-Behnken design to achieve the twin objectives of quantitative determination and removal of Cu(II). FLPSO kinetic model and BS isotherm model fits well with the capacity of 175 mg g−1. Analytical figures of merit includes a linearity range of 10–5,000 µg L−1 (R2 = 0.9986), preconcentration factor of 50 after eluting with 5 mL of 1 M HNO3, LOD of 1.03 µg L−1 and LOQ of 4.5 µg L−1. Accuracy was assessed by analysis of SRM (Standard Reference Material) and recovery experiments after spiking in food samples (Tea, coffee, chocolate, spinach, infant milk substitute) and battery wastewater. Ease of use, reusability (15 cycles), rapid adsorption and high selectivity makes it a promising candidate for efficient and selective removal and trace determination.

Hybrid monolith assisted magnetic ion-imprinted polymer extraction coupled with ICP-MS for determination of trace Au(III) in environmental and mineral samples

In this work, by introducing solvothermal method for generating Fe3O4 nanoparticles and “one-pot” method for synthesizing organic–inorganic hybrid monolithic vinyl functionalized Fe3O4 (Fe3O4@HM), a facile procedure was proposed for preparing poly(1-vinylimidazole) (PVIM) functionalized gold ion imprinted polymer based MNPs@IIP (MNPs@HM@PVIM-Au-IIP). The as-prepared magnetic nanocomposites were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and vibrating sample magnetometry (VSM), etc. After the optimum conditions, including solution pH, adsorption time and sample volume, eluent composition and volume, and elution time were investigated, this MNPs@IIP was employed as ion imprinted polymer magnetic solid phase extraction (II-MSPE) matrix for separation and enrichment of trace gold ions followed by inductively coupled plasma mass spectrometric (ICP-MS) determination with excellent selectivity and sensitivity, and strong anti-interference ability. These merits were benefited from the formation of hybrid monolithic interlayer enduing the resultant MNPs@HM@PVIM-Au-IIP with good chemical and mechanical stability, as well as the dimensional homogeneity due to the solvothermal-generated Fe3O4 nanoparticles as the cores. The applicability superiority of this MNPs@IIP was confirmed by the rapid and efficient extraction of trace level Au(III) in environment water, sediment, soil, coal and ore samples with satisfactory results. The reliability of this II-MSPE-ICP-MS method was also verified by using corresponding Certified Standard Reference materials and spiking recovery of the real samples analyzed.

Potentiometric microsensor based on ion-imprinted polymer for the trace determination of cesium(I) ions

A cesium potentiometric microsensor based on magnetic ion-imprinted polymer (MIIP) has been developed for Cs(I) sensing. The core-shell structure Cs(I)-MIIP was synthesized by surface-imprinting technique, using functionalized magnetic Fe3O4@SiO2 microspheres, Cs(I) ion and carboxymethyl chitosan as supporter, template and functional monomers respectively. The resultant Cs(I)-MIIP was used as ionophore in the construction of the PVC membrane electrode to obtain a selective potentiometric microsensor toward Cs(I) ions. The fabricated sensor exhibited a highly sensitive Nernstian response (60.2 mV/decade) over the concentration range of 1 × 10−6 to 1 × 10−1 M of Cs(I). The response time of the microsensor was considerably short (less than 3 s) and its detection limit was determined as 3.0 × 10−7 M. The microsensor was effectively performed in the pH range of 4–6, and revealed desirable selectivity over a wide variety of other cations including alkali, alkaline earth and heavy metals. The proposed microsensor was also used for the determination of Cs(I) contents in the environmental water samples. The potentiometric results were in good harmony with the results obtained by the ICP-MS method.

A magnetic ion-imprinted polymer composed of silica-coated magnetic nanoparticles and polymerized 4-vinyl pyridine and 2,6-diaminopyridine for selective extraction and determination of lead ions

A novel, sensitive and highly selective magnetic ion-imprinted polymer for facile separation and preconcentration of trace quantities of Pb(ii) ions.

Rapid and selective extraction of trace amount of Pb(II) in aqueous samples using a magnetic ion-imprinted polymer and detection by flame atomic absorption spectrometry

A magnetic Pb(II) ion-imprinted polymer was synthesized using magnetic Fe3O4@SiO2 nanospheres as supporter, n-benzoyl-n-phenyl hydroxylamine as ligand, 4-vinyl pyridine as monomer, ethylene glycol dimethacrylate as crosslinker and 2,2′-azobis(isobutyronitrile) as the initiator. The template was removed from the polymer using 4 mL of HCl (2 mol L-1). The chemical structure, morphology-particle size, elemental analysis, thermal behavior and magnetic properties of the sorbent were evaluated using Fourier-transform infrared spectroscopy, scanning electron microscopy &amp; ImageJ software - Energy dispersive X-ray system, thermal gravimetric analysis and vibrating sample magnetometry. Various parameters such as pH, equilibrium extraction time, temperature and the eluent were optimized. The results showed the sorbent adsorption capacity was 92.3 mg g-1 in pH 6.0 media, equilibrium time of 7 min at 40 °C. Calibration linearity was 2-150 µg L-1 with detection limit of 0.3 µg L-1. The prepared sorbent had high selectivity and was successfully applied to the removing of lead in real samples.

Ultrasonic-assisted micro solid phase extraction of arsenic on a new ion-imprinted polymer synthesized from chitosan-stabilized pickering emulsion in water, rice and vegetable samples.

Pickering emulsion polymerization has been employed for the Ultrasonic assisted-micro solid phase extraction (UA-µSPE) of ultra trace arsenic species by a new magnetic ion imprinted polymer (MIIP) prior to hydride generation atomic absorption spectrometry. 2-acetyl benzofuran thiosemicarbazone (2-ABT) as a new chelating agent and core- shell hydrophobic magnetic nanoparticles was synthesized and the polymerization was carried out at the presence of arsenic - ligand complex, crosslinker, monomer, initiator, stabilizing agent and water-oil emulsion magnetic carrier. In second step, the nanoparticles and polymers were characterized. The analytical parameters such as pH, amount of polymer and ultrasonic time were selected and optimozed by Plackett-Burman and Box-Behnken designs respectively. Linear dynamic range, detection limit and relative standard deviation were 0.01-85.000 µg·L-l, 0.003 µg·L-l, and 3.21%, respectively. The proposed preconcentration procedure was successfully applied to the determination of arsenic ion in a wide range of food samples with different and complex matrixes.

Novel ion imprinted polymer electrochemical sensor for the selective detection of lead(II)

The application of a novel Pb2+ selective sensor based on the ionic imprinted polymer in determining trace levels of lead in natural water and in fruit juice was investigated using differential pulse voltammetry (DPV). The new and selective magnetic ion-imprinted polymer (Fe3O4@SiO2@IIP) was synthesized using 2-(2-aminophenyl)-1H-benzimidazole and 4-vinyl pyridine as a ligand and functional monomer, respectively. The new polymer was utilized for modifying a GCE to generate a new electrochemical sensor. Box–Behnken design (BBD) was utilized for optimizing the parameters influencing the peak current. Extremely suitable voltammetric performance was demonstrated for the electrochemical detection of lead with a low detection limit (0.05 ng mL−1), over a wide linear concentration range (0.1–80 ng mL−1). This modified electrode as a novel sensor was utilized for determining Pb(II) ions in natural water and in fruit juice with very reasonable outcomes.

Application of selective solid-phase extraction using a new core-shell-shell magnetic ion-imprinted polymer for the analysis of ultra-trace mercury in serum of gallstone patients

ABSTRACT A new ultrasonically assisted spectrophotometric method was developed using stabilized ion polymer on a modified nano-absorbent as a core- shell-shell absorbent (Fe3O4@SiO2@TiO2–IIP). It has the advantages of further stabilizing the polymer and consequently and much higher efficiency than its conventional adsorbents. The prepared sorbent was characterized and Its parameters were investigated by a Box–Behnken design. The linear dynamic range and limit of detection were 0.20–28.00 µg L−1 and 0.05 µg L−1 respectively. In selectivity study, it was founded that imprinting causes increased affinity of the prepared IIP toward Hg2+ ion. The proposed IIP is considered to be promising and selective sorbent for solid-phase extraction and preconcentration of Hg2+ ion in sera of different types of gallstone patients.

Preparation of a novel magnetic Pd(II) ion-imprinted polymer for the fast and selective adsorption of palladium ions from aqueous solutions.

A novel magnetic ion-imprinted polymer with high accessibility to palladium ions was synthesized via co-precipitation polymerization. Accordingly, a ternary complex composed of PdCl2 as an imprinting ion, 8-aminoquinoline (AQ) as a ligand, and 4-vinyl pyridine (4-VP) as a complexing monomer was applied to Fe3O4@SiO2 as magnetic core, followed by precipitation polymerization using 2-hydroxyethyl methacrylate (2-HEMA) as a co-monomer, ethylene glycol dimethacrylate (EGDMA) as the crosslinker, and 2,2-azobisisobutyronitrile (AIBN) as an initiator in the presence of 2-methoxyethanol as a solvent. The palladium ions were leached out by a solution containing 50% (v/v) HCl. The synthesized polymer was characterized physically and morphologically using different techniques. In order to assess the conditions required for adsorption, as well as the selectivity and reusability, batch adsorption experiments were carried out. The experiments exhibited that the maximum adsorption capacity was about 65.75mgg-1 at 25°C, while the pH solution and the adsorbent dose were 4 and 1gL-1, respectively. Kinetic studies of experimental data demonstrated that they correspond very much to the pseudo-second-order kinetic model. The development of the Langmuir and Freundlich isothermal models on the equilibrium data proved to correspond well to the Langmuir isotherm model. Interferences studies of the magnetic polymer demonstrated higher affinity and discernment for palladium ions than other co-existing ions in the solutions. Spontaneous (ΔG < 0) and exothermic (ΔH < 0) behavior of the adsorption process is confirmed by thermodynamic studies. In addition, the affinity of the spent polymer has not been dramatically reduced over at least five regeneration cycles.

Preparation of magnetic ion imprinted polymer with waste beer yeast as functional monomer for Cd(ii) adsorption and detection.

In this work, a magnetic ion imprinted polymer (MIIP) with specific recognition capability toward cadmium was prepared by a sol–gel method using waste beer yeast, which is a macromolecule biomass, as a functional monomer. The obtained Cd(ii)-MIIP was characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and adsorption experiments. Then, a MIIP adsorbent based magnetic solid phase extraction (MSPE)-graphite furnace atomic absorption (GFAA) method was established to analyze the cadmium content in food and environmental samples. The maximum cadmium adsorption capacities by the MIIP and magnetic non-imprinted polymer (MNIP) were 62.74 and 32.38 mg g−1, respectively. The absorption by the MIIP was fitted using a pseudo-second-order kinetic model. The Cd(ii)-MIIP demonstrated superior absorption capability for selective removal cadmium. The recovery rate of the MIIP was 90.7% after four adsorption–desorption cycles. The calculated Cd(ii) detection limit (S/N = 3) was 0.18 μg L−1 with the relative standard deviation (RSD) equal to ∼3.5% for 10 μg L−1 of Cd(ii) standard solution. Our proposed method was successfully used in detecting Cd(ii) in aqueous samples. The results obtained in this work suggest that the Cd(ii)-MIIPs might be promising adsorbents to remove harmful cadmium ions from aqueous samples.