Electrosynthesis and analytical performances of functionalized poly (pyrrole/β-cyclodextrin) films

The supramolecular complexing properties of cyclodextrins (CDs) have been investigated inside a conducting polymer environment. In this work, we report the synthesis and characterization of a polypyrrole/beta-cyclodextrin (Ppy/beta-CD) film at a glassy carbon (GC) electrode surface. The polypyrrole/beta-cyclodextrin (Ppy/beta-CD) film was prepared by a simple electropolymerization of a 20:1 mixture of the CD and the pyrrole monomer LiClO4 supporting electrolyte. The resulting functionalized polymer film features interesting electrochemical properties such as selective, simultaneous and quantitative detection of some organic compounds of interest such as polyhydroxyphenyls and neurotransmitters derived from pyrogallol and catechol. The fabricated electrochemical sensor exhibits a fast and reversible linear response toward catechol within the concentration range of 1.5 x 10(-7) to 8 x 10(-6) M and towards pyrogallol within the concentration range of 1 x 10(-6) to 1 x 10(-5) M. The detection limit was 4 x 10(-7) and 1.8 x 10(-6) M for catechol and pyrogallol, respectively. Studies of neurotransmitters such as epinephrine, metanephrine and L-dopa (L-3,4-dihydroxyphenytalanine), showed better response toward epinephrine and L-dopa than for metanephrine. Calibration curves for these two neurotransmitters were linear over the concentration range of 1 x 10(-6) to 1 x 10(-5) M. The detection limit was 4 x 10(-6) and 1 x 10(-6), respectively. The complexation capability of the Ppy/beta-CD system is addressed here in terms of structure-electrochemical activity relationship. The mechanical stability of the film is also discussed. Measurements were performed using cyclic voltammetry (CV), scanning electron microscopy (SEM) coupled to energy dispersive analysis of X-ray (EDAX) and electrochemical impedance spectroscopy (EIS). (c) 2004 Elsevier B.V. All rights reserved.