Rods, imprinted polymer

In situ-imprinted polymers [39] To further simplify construction of such sensors we investigated the use of in situ or rod imprinted polymers using the technique pioneered by Matsui et al. (see Chapter 13). Solutions of template, either DEAEMA or AA as functional monomers, EDMA and initiator in the porogen (4 1 octanohdodecanol, w/w) were introduced into 100 x 4.6 mm (i.d.) HPLC columns and polymerised in situ at either 50 or 70°C. These rods were then flushed with MeCN until a stable absorbance and back pressure were obtained. The most selective polymers were those polymerised at 50°C using DEAEMA as the functional monomer, with a functional monomer/template ratio of either 2 1 or 4 1. The latter was chosen for use in the sensor so as to directly compare the results obtained using bulk and in situ imprinted polymers. 

Fig. 13.3. In situ procedure for preparing molecularly imprinted polymer rods.

Fig. 13.4. Typical chromatogram using a molecularly imprinted polymer rod imprinted with theophylline.

CAPACITY FACTOR OF XANTHINE DERIVATIVES ON A THEOPHYLLINE-IMPRINTED POLYMER ROD COLUMN... 

DIASTEREOSELECTIVITY OF CINCHONIDINE(l)-IMPRINTED AND CINCHONINE(2)-IMPRINTED POLYMER RODS... 

Matsui, J. Takeuchi, T. A molecularly imprinted polymer rod as nicotine-selective affinity media prepared with 2-(trifluoromethyl)acrylic add. Anal. Comm. 1997, 34 (7), 199-200. 

Matsui, J. Nicholls, I.A. Takeuchi, T. Molecular recognition in cinchona alkaloid molecular imprinted polymer rods. Anal. Chim. Acta. 1998, 365, 89-93. 

VI. IN SITU PREPARATION OF MOLECULARLY IMPRINTED POLYMER RODS FOR HPLC... 

MATSUI J, KATO T, TAKF.UCHT T, SUZUKI M, YOKOYAMA K, TAMIYA E and KARUBE I (1993), Molecular recognition in continuous polymer rods prepared by a molecular imprinting technique , Anal Chem, 65, 2223-2224. 

Another in situ preparation of molecularly imprinted columns employs dispersion polymerisation, whereby agglomerated polymer particles are obtained [16]. The procedure is similar to the rod preparation a mixture of the chemicals for the polymer preparation, such as a template, a functional monomer, a cross-linker, a porogen and an initiator is put in a column and heated to effect polymerisation. This method also requires polar solvents, such as cyclohexanol-dodecanol and isopropanol-water, to obtain aggregated polymer particles of well-defined micro-sises. A crucial difference with the rod preparation lies in the volume of the porogen used larger volumes of porogens are used in dispersion polymerisation. 

Takeuchi, T. Matsui, J. Miniaturized molecularly imprinted continuous polymer rods. J High Resolut. Chromatogr. 2000, 23 (1), 44-46. 

The early attempts at fabricating molecularly imprinted capillary monoliths adapted the procedure set forth by Frechet and Svec [4] for the in situ preparation of non-MIP macroporous polymer rods for FC separation. In this procedure, porogenic solvents cyclohexanol and dodecanol (80 20 v/v) were used with a methacrylate-based polymer system to produce porous monoliths. When this system was applied to the fabrication of molecularly imprinted monoliths for CEC, the polymers obtained were sufficiently porous but resulted in poor enantiomeric separations [36]. It is thought that the polar-protic nature of the porogens used may have inhibited the formation of well-defined imprints. Polar-protic solvents such as these are often poor porogens for the noncovalent imprinting approach because they interfere... 

Once the imprinting system has been devised to yield favorable monomer-template complexation and the necessary porosity, the preparation of monolithic polymer rods for HPLC is relatively simple. The general protocol detailed below uses an in situ polymerization method developed by Frechet and Svec [4]. This technique was used by Matsui in the preparation of MIP monolith rods for HPLC separation of antimalarial cinchona alkaloids, ( ) cinchonidine and (+) cinchonine, as well as the structural analogues quinidine and quinine [45]. 

Micromonoliths used as sensor recognition elements provide a quick and easy fabrication scheme. One limitation to these monolith sensors was their capacity. The capacity of rod polymers was found to be very low and lower than LC columns packed with MIP particles. However, their ability to separate templates such as chloramphenicol from structurally similar analogues has been shown to be slightly better [47]. This may be an indication that while the number of viable imprinted sites is less, they are of similar selectivity. 

I. Molecular recognition in continuous polymer rods prepared by molecular imprinting technique. Anal. Chem. 1993, 65, 2223-2224. 

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