Molecular Recognition of Phenylalanine Enantiomers onto a Solid Surface Modified with Electropolymerized Pyrrole‐β‐Cyclodextrin Conjugate

We report the electrochemical deposition of a β‐cyclodextrin pyrrole conjugate (Py‐β‐CD) on an electrode surface including i) characterization based on surface‐enhanced Raman scattering and field‐emission scanning electron microscopy; ii) studies of the molecular recognition of enantiomers of phenylalanine methyl ester hydrochlorides (Phe) based on linear sweep voltammetry and a quartz crystal microbalance. The PPy‐β‐CD polymeric layer on a metallic substrate is distinguished by its inhomogeneity, in which both highly ordered β‐CD units and highly disordered polymer chains are observed. The voltammetric recognition results showed that PPy‐β‐CD exhibited a higher sensitivity for d ‐Phe (138±15)×10³ than for l ‐Phe (6±1)×10³ within the concentration range 0.1–0.75 mM (n=3) despite the differences in the polymer arrangement on the surface. A possible mechanism of molecular recognition of phenylalanine enantiomers is discussed.