The Selectivity of Molecularly Imprinted Polymers (original) (raw)
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The Application of Molecularly Imprinted Polymers
Molecularly imprinted technology (MIT) has the characteristics of specificity and high selectivity, which is one of the most promising methodologies. Besides, the polymers are made using MIT as the functional material of solid-phase extraction and chromatographic fractionating and sensor, because of the characteristics of the high selectivity, the better stability and easy preparation. This review introduces the progress in the application of MIT and summarizes its application in the chemistry.
The Selectivity of Polymers Imprinted with Amines
Molecules, 2018
One of the main reasons for making molecularly imprinted polymers (MIPs) has been that MIPs interact selectively with a specific target compound. This claim is investigated here with the example of a widely used type of noncovalent MIP, the MIP for the beta blocker propranolol. Adsorption isotherms of this MIP and of a nonimprinted control polymer (NIP), respectively, have been measured with a series of compounds in the porogen solvent acetonitrile. The results, visualized as "selectivity ladders", show that the MIP binds propranolol and many other amines better than the NIP does, but the selectivity of the MIP is actually inferior to that of the NIP. The selectivity of either polymer for propranolol is modest against many amines, but is remarkable with respect to other compounds. The contribution of imprinting towards selectivity can be better appreciated when three MIPs, made with different amine templates, are compared among themselves. Each MIP is seen to bind its own template slightly better than the other two MIPs do. In media different from the porogen, the selectivity patterns may change substantially. Propranolol seems to have properties that make it stand high on the selectivity scale in different solvents, albeit for different reasons.
Molecularly Imprinted Polymers: Present and Future Prospective
International Journal of Molecular Sciences, 2011
Molecular Imprinting Technology (MIT) is a technique to design artificial receptors with a predetermined selectivity and specificity for a given analyte, which can be used as ideal materials in various application fields. Molecularly Imprinted Polymers (MIPs), the polymeric matrices obtained using the imprinting technology, are robust molecular recognition elements able to mimic natural recognition entities, such as antibodies and biological receptors, useful to separate and analyze complicated samples such as biological fluids and environmental samples. The scope of this review is to provide a general overview on MIPs field discussing first general aspects in MIP preparation and then dealing with various application aspects. This review aims to outline the molecularly imprinted process and present a summary of principal application fields of molecularly imprinted polymers, focusing on chemical sensing, separation science, drug delivery and catalysis. Some significant aspects about preparation and application of the molecular imprinting polymers with examples taken from the recent literature will be discussed. Theoretical and experimental parameters for MIPs design in terms of the interaction between template and polymer functionalities will be considered and synthesis methods for the improvement of MIP recognition properties will also be presented.
Chromatographic characterization of molecularly imprinted polymers
Analytical and Bioanalytical Chemistry, 2008
Recent efforts in the investigation of chromatographic characterization of molecularly imprinted polymers (MIPs) have focused mainly on the nature of heterogeneous binding sites. More data on the thermodynamics than on the kinetic features of MIP columns have been published. The present article addresses the sources of peak broadening and tailing, which are the main drawbacks often associated with imprinted polymers in chromatography for practical applications. With use of the theory of nonlinear chromatography, the peak properties of a MIP column, including the retention and peak broadening and tailing, can be well interpreted. Efforts to improve chromatographic efficiency using MIPs prepared by approaches different from the conventional method, including covalent imprinting and the format of uniformly sized spherical microbeads, are reviewed and discussed. This review leads to the conclusion that nonlinear chromatography theory is useful for characterizing chromatographic features of MIP columns, since a MIP is essentially an affinity-based chromatographic stationary phase. We expect more theoretical and experimental studies on the kinetic aspects of MIP columns, especially the factors influencing the apparent rate constant, as well as the analysis of the influences of mobile-phase composition on the chromatographic performance. In addition to revealing the affinity interaction by molecular recognition, slow nonspecific interactions which may be inherited from the imperfect imprinting and may be involved in the rebinding of the template to MIPs also need to be characterized.
Journal of Chromatography a, 1999
To investigate the extent and nature of the monomer-template association of molecularly imprinted polymer prepolymerisation mixtures, a series of (2)-nicotine molecularly imprinted acrylic polymers was prepared using a range of monomer-template molar ratios. Load capacity studies performed in the chromatographic mode showed an unexpected increase in retention at higher nicotine sample loads. Further analyses of this effect indicate that solvation effects, and potentially the presence of higher order template complexes, may explain this behaviour. The implications of these results are discussed in terms of the current model for molecular imprinting, and it is suggested that the possibility of template self-association should be included in this model.
A historical perspective and the development of molecular imprinting polymer-a review
2015
Molecular imprinting is an emerging technology which enables us to synthesize the materials with highly specific receptor sites towards the target molecules. Molecularly imprinted polymers (MIPs) are a class of highly cross-linked polymer that can bind certain target compound with high specificity. Such techniques have been progressively employed in a wide scope of applications such as development of various analytical techniques such as solid-phase extraction (SPE), liquid chromatography, capillary electro chromatography, binding assays and biosensors, mostly in bio-analytical areas. The aim of this review paper is to give a fundamental description of the molecular imprinted polymer and to give the reader an insight into the main developments are discussed, Particular emphasis will be placed on their role as affinity materials in separation science. Discussing first general aspects in MIP history and preparation and then dealing with various application aspects.
Which molecularly imprinted polymer is better?
Analytica Chimica Acta, 2007
Molecularly imprinted polymers (MIP) have been successfully synthesized toward many different compounds in the last decades. The mechanistic details of selective binding at binding sites are not yet well understood. For this reason the characterization of MIP binding has been mostly phenomenological and this makes the transfer of results between different laboratories or between different types of applications difficult. In this paper we analyze the relationship between different types of characterization like isotherms, binding site models, chromatographic k and α values, etc. as they relate to different applications like HPLC, solid phase extraction (SPE), binding assays, batch extraction and sensors. It is shown that α values determined by elution chromatography depend on seemingly irrelevant factors as the length and diameter of the column, respectively. The determination of distribution ratios or partition coefficients is proposed as an easily understandable and useful quantity in the characterization of novel MIPs. Data used for the characterization of a MIP should be transferable between different applications but the qualification of MIPs as better or worse will depend on the application in case.
Binding assays with molecularly imprinted polymers—why do they work?
Journal of Chromatography B, 2004
The design of homologous displacement ligand binding assays based on molecularly imprinted polymers (MIP) is discussed in terms of the MIP adsorption isotherm. It is shown that only MIPs having a binding isotherm with varying slope are suitable for the assay, but there is no need to interpret the isotherm in terms of site affinity and population. One can calculate the calibration plot of the binding assay from the isotherm and vice versa.
Selective sample treatment using molecularly imprinted polymers
Journal of Chromatography A, 2007
The molecularly imprinted polymers (MIPs) are synthetic polymers possessing specific cavities designed for a target molecule. By a mechanism of molecular recognition, the MIPs are used as selective sorbents for the solid-phase extraction of target analytes from complex matrices. MIPs are often called synthetic antibodies in comparison with immuno-based sorbents; they offer some advantages including easy, cheap and rapid preparation and high thermal and chemical stability. This review describes the use of MIPs in solid-phase extraction with emphasis on their synthesis, the various parameters affecting the selectivity of the extraction, their potential to selectively extract analytes from complex aqueous samples or organic extracts, their on-line coupling with LC and their potential in miniaturized devices.