Molecularly imprinted polymer techniques

Sellergren B (ed) (2001) Molecularly imprinted polymers - techniques and instrumentation in analytical chemistry 23, 1st Edn. Elsevier, Amsterdam... 

The new strategy for chiral separation in chromatography and capillary electrophoresis is the development of molecularly imprinted polymers. First of all, Wulf et al. [141] presented the idea of a molecularly imprinted polymers technique. This involves the incorporation of a target molecule (an imprint molecule) into a polymer and the removal of the print molecule, to leave a substrate selective site or cavities. This may be achieved either by... 

M. Shekarchi, M. Pourfarzib, B. Akbari-Adergani, A. Mehramizi, M. Javanbakht and R. Dinarvand, Selective extraction of lamivudine in human serum and urine using molecularly imprinted polymer technique, / Chromatogr. B, 931 50-55, 2013. 

Advanced techniques like molecularly imprinted polymers (MIPs), infrared/near infrared spectroscopy (FT-IR/NIR), high resolution mass spectrometry, nuclear magnetic resonance (NMR), Raman spectroscopy, and biosensors will increasingly be applied for controlling food quality and safety. 

The most widely employed techniques for the extraction of water samples for triazine compounds include liquid-liquid extraction (LLE), solid-phase extraction (SPE), and liquid-solid extraction (LSE). Although most reports involving SPE are off-line procedures, there is increasing interest and subsequently increasing numbers of reports regarding on-line SPE, the goal of which is to improve overall productivity and safety. To a lesser extent, solid-phase microextraction (SPME), supercritical fluid extraction (SEE), semi-permeable membrane device (SPMD), and molecularly imprinted polymer (MIP) techniques have been reported. 

Among the techniques listed in Section 1.2.1, the two most documented approaches in addition to SPE, LLE, and PPT are solid phase microextraction (SPME) and affinity capture of analytes based on molecularly imprinted polymers (MIPs). Recent developments in these areas are briefly discussed below. 

This section will illustrate the MIP technique for sample preparation by presenting examples of diazepam and its metabolites in hair samples.177 An anti-diazepam molecularly imprinted polymer... 

Recent trends in pesticide analysis in food aims for reduced sample pretreatments or simplified methodologies (as QuEChERS approaches), the use of online purification processes, the use of new adsorbents (such as molecular imprinted polymers (MIPs) and nanomaterials) for the extraction and clean-up processes, and focused on the development of large multiresidue methods, most of them based on LC-MS/ MS. In spite of the relevant role of LC-MS/MS, GC-MS-based methods still play an important role in pesticide analysis in food. Despite the development achieved in the immunochemical approaches, the need for multi-residue methods has supported the development and use of instrumental techniques. 

A novel approach to guest inclusion by dendrimers is the use of molecular imprinting . We will look at molecular imprinted polymers in more detail in Section 14.3. Generally the imprinting technique involves assembly of a covalent polymer - in this case dendrimer - about the target guest which acts... 

There are several future trends for the development of passive sampling techniques. The first is the development of devices that can be used to monitor emerging environmental pollutants. Recently, attention has shifted from hydrophobic persistent organic pollutants to compounds with a medium-to-high polarity, for example, polar pesticides, pharmaceuticals, and personal care products.82 147148 Novel materials will need to be tested as selective receiving phases (e.g., ionic liquids, molecularly imprinted polymers, and immunoadsorbents), together with membrane materials that permit the selective diffusion of these chemicals. The sample extraction and preconcentration methods used for these devices will need to be compatible with LC-MS analytical techniques. 

New in situ techniques with enhancements in sensitivity and selectivity (sensors based on molecular imprinted polymers)... 

The basic concepts in forming a molecularly imprinted polymer are therefore rather simple. Indeed this apparent simplicity has misled some would-be users of this approach who have failed to appreciate that realising this in practice, particularly with any degree of efficiency, has proved enormously difficult. Not the least, most polymer chemists would appreciate that to produce a crosslinked polymeric network sufficiently rigid to retain some memory of an imprint molecule, and yet allow ready mass transfer of molecules to and from the memory cavities, is no small undertaking. The early workers in the field have made enormous efforts to bring the technique to a point where materials capable of application and exploitation are now becoming available, and this is as much a tribute to their tenacity as it is to their scientific invention. 

A molecularly imprinted polymer is an artificial antibody that is tailored for a specific molecule. The in situ technique introduces another attractive feature, in that the imprinted polymer is tailor-made for a specific application with a minimum of experimental steps, emphasising the original statement that imprinted polymers can be easily and simply prepared and applied. It is also shown that the in situ method is useful for designing a molecular imprinting system and would be helpful for mechanistic studies of molecular imprinting and recognition. Thus, advances in the basics and applications of molecular imprinting can be expected by this technique. 

Sellergren, Borje. Molecularly Imprinted Polymers Man-Made Mimics of Antibodies and Their Applications in Analytical Chemistry. Vol. 23 of Techniques and Instrumentation in Analytical Chemistry. New York Elsevier, 2001. 

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