Molecularly Imprinted Polypyrrole Prepared by Electrodeposition for the Selective Recognition of Tryptophan Enantiomers

Herein we report the electrosynthesis of polypyrrole with L-tryptophan (L-Trp) as a template to prepare molecularly imprinted polymers (MIPs). Overoxidized polypyrrole films with cavities complementary to the template were used for the enantioselective detection Of L-Trp and D-tryptophan (D-Trp). Important parameters, such as the electropolymerization potential, overoxidization potential and time, thickness of the polypyrrole films, and scanning rate of the stripping voltammetric experiments, were varied to achieve an optimum sensor response. We found that L-Trp was inserted about 2 times higher into the imprinted polymer film than DTrp. Also, in this study, an electrochemical quartz crystal microbalance technique was used to investigate the performance of overoxidized polypyrrole films. The enantioselectivity of the MIPs was attributed to the cavities in the imprinted films, which were complementary to the target molecules, both in shape and in positioning of the functional groups. The results also suggest the feasibility of preparing MIPs by electropolymerization for the enantioselective recognition of other amino acid enantiomers. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 1952-1957, 2010