Imprinted polymer ISEs

The first imprinted polymer ISEs were prepared for calcium and magnesium ions by Mosbach s group [18]. The monomer used in the fabrication of the electrode was 

Ionic sensors based on molecularly imprinted polymers 

Although not an ion, glucose can be detected by virtue of an MIP-derived ion. The pH electrode is simply an ISE for H . Glass and ion-selective field effect transistors pH electrodes are the best characterised and the most successful ISEs. Many sensors employ chemical reactions to produce H or OH ions and employ pH electrodes for signal transduction. An imprinted sensor based on this approach is the glucose sensor produced by Arnold s group [10]. This polymer employs a metal ion (Cu ) in the imprinted site and makes use of the metal s 

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ISEs are selective but not exclusive, so they may respond to other chemically similar ions and careful control of the cell contents is usually required. MIPs provide a means for selectivity enhancement and it is likely that electrodes made using imprinted polymers may more closely approach the exclusivity desired in such a device. A calibration plot for a typical imprinted polymer ISE is given in Fig. 19.2. 

Fig. 19.2. The potential response of an imprinted polymer ISE for Pb used in a cell with an Ag/AgCl reference electrode. The slope is 27.6 mV/decade and the line fitted to the data gives a correlation constant, r = 0.9996.

Molecularly imprinted polymers (MIPs) can be prepared according to a number of approaches that are different in the way the template is linked to the functional monomer and subsequently to the polymeric binding sites (Fig. 6-1). Thus, the template can be linked and subsequently recognized by virtually any combination of cleavable covalent bonds, metal ion co-ordination or noncovalent bonds. The first example of molecular imprinting of organic network polymers introduced by Wulff was based on a covalent attachment strategy i.e. covalent monomer-template, covalent polymer-template [12]. 

Toth E, Hehn L, Merbach AE (2002) Relaxivity of MRI Contrast Agents. 221 61-101 Tovar GEM, Krauter I, Gruber C (2003) Molecularly Imprinted Polymer Nanospheres as Fully Affinity Receptors. 227 125-144... 

Yano, K. and Karube, I., Molecularly imprinted polymers for biosensor applications. Trends Anal. Chem., 18, 199, 1999. 

L.I. Andersson, in Solid Phase Extraction on Molecularly Imprinted Polymers Requirements, Achievements and Future Work, S. Piletsky and A. Turner (Eds.), Landes Biosciences, New York, 2006. 

Different classifications for the chiral CSPs have been described. They are based on the chemical structure of the chiral selectors and on the chiral recognition mechanism involved. In this chapter we will use a classification based mainly on the chemical structure of the selectors. The selectors are classified in three groups (i) CSPs with low-molecular-weight selectors, such as Pirkle type CSPs, ionic and ligand exchange CSPs, (ii) CSPs with macrocyclic selectors, such as CDs, crown-ethers and macrocyclic antibiotics, and (iii) CSPs with macromolecular selectors, such as polysaccharides, synthetic polymers, molecular imprinted polymers and proteins. These different types of CSPs, frequently used for the analysis of chiral pharmaceuticals, are discussed in more detail later. 

Nantasenamat C, Isarankura-Na-Ayudhya I, Naenna T et al. (2007) Quantitative stracture-imprinting factor relationship of molecularly imprinted polymers. Biosens Bioelectron 2007 3309-3317... 

Figure 20-23 (a) Surface plasmon resonance spectrum of sensor coated with molecularly imprinted polymer that selectively binds NAD+. (b) Response of sensor to four similar molecules shows largest response to NAD+, which was the template for polymerization. [From O. A. Raitman. V. I. Chegel, a B. Kharitonov. M. Zayats. E. Katz, and I. Winner. Analysis of NAD(P) and NAD(P)H Cofactors by Means of Imprinted Polymers Associated with Au Surfaces A Surface Plasmon Resonance Study. Anal. CNm. Ada 2004,504. 101.]... 

Ferrer I et al (2000) Selective trace enrichment of chlorotriazine pesticides from natural waters and sediment samples using terbuthylazine molecularly imprinted polymers. Anal Chem 72(16) 3934-3941... 

A different approach was used by Emgenbroich and Wulff [42] to develop imprinted polymers with enantioselective esterase activity. The system was based on the use of an amidinium functional monomer (33), already developed earlier by the same group, but in this case a chiral phosphonate (62) was used as imprinting TSA in order to catalyse the hydrolysis of the corresponding chiral ester (63). The polymer imprinted with the L-enantiomer was able to enhance the esterolytic activity 325-fold when compared with the background and 80 times compared to the non-imprinted polymer. The ratio between the two rates constant, Lai-i/L ii-i) = 1 -4, can be taken as a measure of the enantioselective efficiency of the reaction. 

The procedure for extraction of the antibiotic oxacillin using oxacillin imprinted polymer involved the following steps (i) spiked milk samples... 

LEVI R, MCNIVEN S, PTT.F.TSKY S, CHEONG S H, YANO K and KARUBE I (1997), Optical detection of chloramphenicol using molecularly imprinted polymers , Anal Chem, 69, 2017-2021. 

Shoji, R., T. Takeuchi, and I. Kubo (2003). Atrazine sensor based on molecularly imprinted polymer-modified gold electrode. Anal. Chem., 75(18) 4882-4886. 

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