Characterization of Overoxidized Polypyrrole Colloids Imprinted with l-Lactate and Their Application to Enantioseparation of Amino Acids

Overoxidized polypyrrole colloids imprinted with l-lactate were prepared to evaluate the performance of the overoxidation pseudo-template technique developed by the authors. A polypyrrole colloid that had been prepared from a mixture of monomer (pyrrole), dopant (l-lactate), steric stabilizer (poly(...

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Bibliographic Details
Published in:	Analytical chemistry (Washington) Vol. 74; no. 16; pp. 4184 - 4190
Main Authors:	Okuno, Hiroyuki, Kitano, Tomomi, Yakabe, Hidetaka, Kishimoto, Masayoshi, Siigi, Hiroshi, Nagaoka, Tsutomu
Format:	Journal Article
Language:	English
Published:	Washington, DC American Chemical Society 15-08-2002
Subjects:	Alanine - isolation & purification Amino acids Amino Acids - chemistry Amino Acids - isolation & purification Analytical chemistry Biosensing Techniques - methods Chemistry Colloids - chemistry Electrochemical methods Electrochemistry - methods Exact sciences and technology Lactic Acid - chemistry Molecules Oxidation Oxidation-Reduction Polymers - chemistry Pyrroles - chemistry Stereoisomerism Characterization Lactates Chemical analysis Oxidized state Separation Aminoacid Imprinting Enantiomer Pyrrole Polymer Colloid
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Summary:	Overoxidized polypyrrole colloids imprinted with l-lactate were prepared to evaluate the performance of the overoxidation pseudo-template technique developed by the authors. A polypyrrole colloid that had been prepared from a mixture of monomer (pyrrole), dopant (l-lactate), steric stabilizer (poly(vinylpyrrolidone)) and oxidizing agent (peroxodisulfate) was electrochemically overoxidized at +1.5 V vs Ag\|AgCl to create a complementary cavity for recognition of the molecules, which were structurally similar to dopant, through dedoping. As a target molecule for enantioselective uptake into the overoxidized colloid, we selected alanine, which is structurally different from the template (lactate) only in one side chain (alanine, −NH2; lactic acid, −OH). The overoxidized polypyrrole colloid showed higher affinity for l-alanine than for d-alanine, and an uptake ratio (l/d) of as high as 11 ± 4 was observed under optimum conditions. Uptake reached equilibrium in 10 min, thanks to the high surface area and short diffusion length in the colloidal particle. Further, to confirm the complementarity of the cavity, the effect of side chain size on uptake of several α-amino acids was examined to indicate that the uptake amount decreased with increasing molecular volume of the l-amino acids.
Bibliography:	ark:/67375/TPS-G4C5FP3G-0 istex:AD9946A4376649F5D111FBEA26390C3CE18D2206 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0003-2700 1520-6882
DOI:	10.1021/ac025822o