Ion Selective Molecularly Imprinted Materials

Zhang, Z. Zhang, H. Hu, Y. Yang X Yao, S. (2010d). Novel surface molecularly imprinted material modified multi walled carbon nanotubes as solid phase extraction sorbent for selective extraction gallium ion from fly ash. Talanta, 82, 304-311. 

Acid/base chemistry is also an obvious reaction path for selective detection of a variety of materials. For example, acid/base reaction can be made to occur within a molecularly imprinted pocket to assist in differentiating the molecule of choice before deprotonating it to produce an ion pair that then interacts with the evanescent field. This approach is currently being used to selectively detect TNT to levels in the low parts-per-trillion. 2,4,6-trinitrotoluene, a potent explosive, is also a weak acid having a p/sTa of approximately 14.5 [38]. A TNT derivative is synthesized with a tether to a silane. The silane is chosen so the group can be... 

Scheme 9.10. Source of enantioselectivity in imprinted ligand-exchange materials. Molecular imprinting with L-Phe gives a cavity that is selective for L-Phe. (a) The L-isomer can simultaneously chelate to metal ion and fit into the shape-selective cavity, (b) Rebinding of the d-isomer is hindered because chelation of the metal ion by the o-isomer is sterically unfavourable. (c) Alternatively, if the molecule fits into the cavity, it cannot chelate Cu(Il).

Here, Q is the initial solution concentration and Cf is the final solution concentration. Comparison of the k values for the imprinted and control blank gels can show the effect of imprinting on the metal-ion selectivity for a given material. A measure of the increase in selectivity due to molecular imprinting can be defined by the ratio of the selectivity coefficients of the imprinted (MIP) and nonimprinted (NP) materials ... 

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