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Imprinted Polymer (imprinted + polymer)
Selected AbstractsSynthesis of an Enzyme-like Imprinted Polymer with the Substrate as the Template, and Its Catalytic Properties under Aqueous ConditionsCHEMISTRY - A EUROPEAN JOURNAL, Issue 14 2004Zhiyong Cheng Dr. Abstract Transition state analogues (TSAs) have long been regarded as ideal templates for the preparation of catalytically active synthetic imprinted polymers. In the current work, however, a new type of molecularly imprinted polymer (MIP) was synthesized with the substrate (homovanillic acid, HVA) as the template and hemin introduced as the catalytic center, with the use of plural functional monomers to prepare the active sites. The MIP successfully mimicked natural peroxidase, suggesting that it may not be imperative to employ a TSA as the template when preparing enzyme-like imprinted polymers and that the imprinted polymer matrix provided an advantageous microenvironment around the catalytic center (hemin), essentially similar to that supplied by apo-proteins in natural enzymes. Significantly, by taking advantage of the special structure of hemin and multiple-site interactions provided by several functional monomers, the intrinsic difficulties for MIPs in recognizing template molecules in polar solutions were overcome. The newly developed polymer showed considerable recognizing ability toward HVA, catalytic activity, substrate specificity and also stability, which are the merits lacked by the natural peroxidase. Meanwhile, the ease of recovery and reuse the MIP implies the potential for industrial application. [source] Novel Potentiometric Sensors of Molecular Imprinted Polymers for Specific Binding of ChlormequatELECTROANALYSIS, Issue 2 2008Ayman Abstract Molecularly imprinted polymers (MIP) were used as potentiometric sensors for the selective recognition and determination of chlormequat (CMQ). They were produced after radical polymerization of 4-vinyl pyridine (4-VP) or methacrylic acid (MAA) monomers in the presence of a cross-linker. CMQ was used as template. Similar non-imprinted (NI) polymers (NIP) were produced by removing the template from reaction media. The effect of kind and amount of MIP or NIP sensors on the potentiometric behavior was investigated. Main analytical features were evaluated in steady and flow modes of operation. The sensor MIP/4-VP exhibited the best performance, presenting fast near-Nernstian response for CMQ over the concentration range 6.2×10,6,1.0×10,2,mol L,1 with detection limits of 4.1×10,6,mol L,1. The sensor was independent from the pH of test solutions in the range 5,10. Potentiometric selectivity coefficients of the proposed sensors were evaluated over several inorganic and organic cations. Results pointed out a good selectivity to CMQ. The sensor was applied to the potentiometric determination of CMQ in commercial phytopharmaceuticals and spiked water samples. Recoveries ranged 96 to 108.5%. [source] Flow-Through Assay of Quinine Using Solid Contact Potentiometric Sensors Based on Molecularly Imprinted PolymersELECTROANALYSIS, Issue 24 2009Ayman Abstract Miniaturized potentiometric membrane sensors for quinine incorporated with molecular imprinted polymer (MIP) were synthesized and implemented. Planar PVC based polymeric membrane sensors containing quinine-methacrylic and/or acrylic acid-ethylene glycol methacrylate were dispensed into anisotropically etched wells on polyimide wafers. The determination of quinine was carried out in acidic solution at pH,6, where positively charged species predominated prevalently. The suggested miniaturized planner sensors exhibited marked selectivity, sensitivity, long-term stability and reproducibility. At their optimum conditions, the sensors displayed wide concentration ranges of 4.0×10,6,1.0×10,2mol L,1 and 1.0×10,5,1.0×10,2 mol L,1 with slopes of about 61.3,55.7,mV decade,1; respectively. Sensors exhibit detection limits of 1.2×10,6 and 8.2×10,6 mol L,1 upon the use of methacrylic and acrylic acid monomers in the imprinted polymer, respectively. Validation of the assay method according to the quality assurance standards (range, within-day repeatability, between-day variability, standard deviation, accuracy, and good performance characteristics) which could assure good reliable novel sensors for quinine estimation was justified. Application of the proposed flow-through assay method for routine determination of quinine in soft drinks was assayed and the results compared favorably with data obtained by the standard fluorimetric method. [source] A Substrate-Selective Nanoreactor Made of Molecularly Imprinted Polymer Containing Catalytic Silver NanoparticlesADVANCED FUNCTIONAL MATERIALS, Issue 16 2009Song jun Li Abstract An original, substrate-selective nanoreactor is designed and characterized. The nanoreactor made of a 4-nitrophonel (NP)-imprinted polymer and Ag nanoparticles, can specifically recognize NP compared with its analogues 4-nitrophenyl acetate (NPA) and 2,6-dimethyl-4-nitrophenol (DNP). Under comparable conditions, this nanoreactor significantly accelerated the reduction of NP; however, much less acceleration is shown for its analogues. Unlike traditional Ag nanoreactors, which lack molecular recognition abilities, this unique nanoreactor is composed of molecularly imprinted networks, making substrate-selective catalysis feasible. [source] Metal ion-imprinted polymer microspheres derived from copper methacrylate for selective separation of heavy metal ionsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Anh Hoang Dam Abstract Microbeads of metal ion-imprinted polymers (MIIPs) were prepared by a novel precipitation polymerization technique, in which copper methacrylate monomer and ethylene glycol dimethacrylate crosslinker were copolymerized in a rotary evaporator. The prepared microbeads had mono- or narrow size dispersity, and their sizes increased from 1 to 4 ,m with decreasing solvent amount or increasing initiator concentration. The absorption capacity and selectivity of the imprinted polymer for copper ion were determined in the presence of various competitive metal ions. As results, adsorption equilibrium was quickly achieved in about 10 min with high absorbability (about 90%). The effects of pH, initial metallic ion concentration, and MIIP bead size on the absorption capacity were investigated. The Cu(II)-imprinted polymers exhibited extremely high selectivity, which was much higher than that of corresponding blank polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 [source] Fluorescent, molecularly imprinted thin-layer films based on a common polymer,JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Piotr Cywinski Abstract Fluorescent, molecularly imprinted polymer thin films, with cyclic guanosine 3,,5,-monophosphate (cGMP) as a template and 1,2-diphenyl-6-vinyl-1H -pyrazole-[3,4- b]-quinoline as a fluorescent receptor, were prepared according to a method based on commercially available poly (methyl methacrylate). This method of preparation predicts photoinduced crosslinking in the mixture of polymer chains and involved components. The advantages of this method are the relative simplicity of its preparation and the fact that a common polymer can be used. The spin-coated thin-layer films of imprinted and nonimprinted polymers were studied with the use of fluorescence microscopy with a scanning range of 80 × 80 ,m. A strong fluorescence quenching effect was observed when a cGMP-imprinted film was incubated in aqueous solutions of cGMP, but a comparatively small effect was observed for a nonimprinted polymer and when an imprinted film was incubated with cyclic adenosine 3,,5,-monophosphate (cAMP). The separation factor by the imprinted polymer was determined to be 2.55 for cGMP against cAMP. The obtained polymeric sensor appeared to be stable during subsequent measurements after rewashing and readsorption. The homogeneity of the surface of the polymer film, dependent on the method of film preparation, was also studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 229,235, 2007 [source] Molecularly imprinted polymer for selective extraction of endocrine disrupters nonylphenol and its ethoxylated derivates from environmental solidsJOURNAL OF SEPARATION SCIENCE, JSS, Issue 13 2008Laura Núñez Abstract Nonylphenol isomers (NP), linear nonylphenol (4-n-NP) and NP short chain ethoxylated derivates (NPEO1 and NPEO2) are degradation products of nonylphenol polyethoxylates, a worldwide used group of surfactants. All of them are considered endocrine disrupters due to their ability to mimic natural estrogens. In this paper, the preparation and evaluation of several 4-n-NP molecularly imprinted polymers (MIPs) for the selective extraction and clean-up of 4-n-NP, NP, NPEO1 and NPEO2 from complex environmental solid samples is described. Among the different combinations tested, a methacrylic acid-based imprinted polymer prepared in toluene provided the better performance for molecularly imprinted SPE (MISPE). Under optimum MISPE conditions, the polymer was able to selectively retain not only linear NP but also the endocrine disruptors NPEO1, NPEO2 and NP with recoveries ranging from 60 to 100%, depending upon the analyte. The developed MISPE procedure was successfully used for the determination of 4-n-NP, NP, NPEO1 and NPEO2 in sediments and sludge samples at concentration levels according to data reported in the literature for incurred samples. Finally, various sludge samples collected at five different sewage treatment plants from Madrid and commercial sludge for agriculture purposes were analysed. The measured concentrations of the different compounds varied from 3.7 to 107.5 mg/kg depending upon the analyte and the sample. [source] Sensors for the Detection and Quantification of Bacterial Contamination in Water for Human Use,ADVANCED ENGINEERING MATERIALS, Issue 5 2010Raquel Barbosa Queirós The deterioration of water quality by Cyanobacteria cause outbreaks and epidemics associated with harmful diseases in Humans and animals because of the toxins that they release. Microcystin-LR is one of the hepatotoxins most widely studied and the World Health Organization, recommend a maximum value of 1,µg,L,1 in drinking water. Highly specific recognition molecules, such as molecular imprinted polymers are developed to quantify microcystins in waters for human use and shown to be of great potential in the analysis of these kinds of samples. The obtained results were auspicious, the detection limit found, 1.5,µg,L,1, being of the same order of magnitude as the guideline limit recommended by the WHO. This technology is very promising because the sensors are stable and specific, and the technology is inexpensive and allows for rapid on-site monitoring. [source] Metal ion-imprinted polymer microspheres derived from copper methacrylate for selective separation of heavy metal ionsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Anh Hoang Dam Abstract Microbeads of metal ion-imprinted polymers (MIIPs) were prepared by a novel precipitation polymerization technique, in which copper methacrylate monomer and ethylene glycol dimethacrylate crosslinker were copolymerized in a rotary evaporator. The prepared microbeads had mono- or narrow size dispersity, and their sizes increased from 1 to 4 ,m with decreasing solvent amount or increasing initiator concentration. The absorption capacity and selectivity of the imprinted polymer for copper ion were determined in the presence of various competitive metal ions. As results, adsorption equilibrium was quickly achieved in about 10 min with high absorbability (about 90%). The effects of pH, initial metallic ion concentration, and MIIP bead size on the absorption capacity were investigated. The Cu(II)-imprinted polymers exhibited extremely high selectivity, which was much higher than that of corresponding blank polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 [source] Comparison of monofunctional and multifunctional monomers in phosphate binding molecularly imprinted polymersJOURNAL OF MOLECULAR RECOGNITION, Issue 6 2008Xiangyang Wu Abstract In this study, molecularly imprinted polymers (MIPs) prepared using a multifunctional and a monofunctional monomer were compared with respect to their affinities, selectivities, and imprinting efficiencies for organophosphates. This is of interest because multifunctional monomers have higher affinities than traditional monofunctional monomers for their target analytes and thus should yield MIPs with higher affinities and selectivities. However, polymers containing multifunctional monomer may also have a higher number of unselective, non-templated binding sites. This increase in background binding sites could lead to a decrease in the magnitude of the imprinting effect and in the selectivity of the MIP. Therefore, phosphate selective imprinted and non-imprinted polymers (NIPs) were prepared using a novel multifunctional triurea monomer. The binding properties of these polymers were compared with polymers prepared using a monofunctional monourea monomer. The binding affinities and selectivities of the monomers, imprinted polymers, and NIPs were characterized by NMR titration, binding uptake studies, and binding isotherms. MIPs prepared with the triurea monomer showed higher binding affinity and selectivity for the diphenylphosphate anion in organic solvents than the MIPs prepared with the monofunctional monomer. Surprisingly, the binding properties of the NIPs revealed that the polymers prepared using the multifunctional and monofunctional monomers were very similar in affinity and selectivity. Thus, the multifunctional monomers increase not only the affinity of the MIP but also enhance the imprinting effect. Copyright © 2008 John Wiley & Sons, Ltd. [source] Synthesis of an Enzyme-like Imprinted Polymer with the Substrate as the Template, and Its Catalytic Properties under Aqueous ConditionsCHEMISTRY - A EUROPEAN JOURNAL, Issue 14 2004Zhiyong Cheng Dr. Abstract Transition state analogues (TSAs) have long been regarded as ideal templates for the preparation of catalytically active synthetic imprinted polymers. In the current work, however, a new type of molecularly imprinted polymer (MIP) was synthesized with the substrate (homovanillic acid, HVA) as the template and hemin introduced as the catalytic center, with the use of plural functional monomers to prepare the active sites. The MIP successfully mimicked natural peroxidase, suggesting that it may not be imperative to employ a TSA as the template when preparing enzyme-like imprinted polymers and that the imprinted polymer matrix provided an advantageous microenvironment around the catalytic center (hemin), essentially similar to that supplied by apo-proteins in natural enzymes. Significantly, by taking advantage of the special structure of hemin and multiple-site interactions provided by several functional monomers, the intrinsic difficulties for MIPs in recognizing template molecules in polar solutions were overcome. The newly developed polymer showed considerable recognizing ability toward HVA, catalytic activity, substrate specificity and also stability, which are the merits lacked by the natural peroxidase. Meanwhile, the ease of recovery and reuse the MIP implies the potential for industrial application. [source] | |||||||||||||