title: Guest-host complex formed between ascorbic acid and β-cyclodextrin immobilized on the surface of an electrode.
abstract: This work deals with the formation of supramolecular complexes between ascorbic acid (AA), the guest, and β-cyclodextrin (β-CD), the host, that was first potentiodynamically immobilized on the surface of a carbon paste electrode (CPE) throughout the formation of a β-CD-based conducting polymer (poly-β-CD). With the bare CPE and the β-CD-modified CPE, an electrochemical study was performed to understand the effect of such surface modification on the electrochemical response of the AA. From this study it was shown that on the modified-CPE, the AA was surface-immobilized through formation of an inclusion complex with β-CD, which provoked the adsorption of AA in such a way that this stage became the limiting step for the electrochemical oxidation of AA. Moreover, from the analysis of the experimental voltammetric plots recorded during AA oxidation on the CPE/poly-β-CD electrode surfaces, the Gibbs' standard free energy of the inclusion complex formed by the oxidation product of AA and β-CD has been determined for the first time, ∆G0inclus = -36.4 kJ/mol.
authors.affiliation: Departamento de Química, Universidad Autónoma Metropolitana Iztapalapa, Av. San Rafael Atlixco #186, Col. Vicentina, Mexico D.F. C.P. 09340, Mexico. mtrs218@xanum.uam.mx.
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Ramírez-Silva
authors.affiliation: Departamento de Materiales, Universidad Autónoma Metropolitana Azcapotzalco, Av. San Pablo #180, Col. Reynosa-Tamaulipas, Mexico D.F. C.P. 02200, Mexico. mepp@correo.azc.uam.mx.
authors.forename: Manuel
authors.initials: M
authors.lastname: Palomar-Pardavé
authors.affiliation: Departamento de Materiales, Universidad Autónoma Metropolitana Azcapotzalco, Av. San Pablo #180, Col. Reynosa-Tamaulipas, Mexico D.F. C.P. 02200, Mexico.
authors.forename: Silvia
authors.initials: S
authors.lastname: Corona-Avendaño
authors.affiliation: Departamento de Materiales, Universidad Autónoma Metropolitana Azcapotzalco, Av. San Pablo #180, Col. Reynosa-Tamaulipas, Mexico D.F. C.P. 02200, Mexico. mmrr@correo.azc.uam.mx.
authors.forename: Mario
authors.initials: M
authors.lastname: Romero-Romo
authors.affiliation: Departamento de Sistemas Biológicos, Universidad Autónoma Metropolitana Xochimilco, Calzada del Hueso 1100, Col. Villa Quietud, Delegación Coyoacán, Mexico D.F. C.P. 04960, Mexico. ageorgina@hotmail.com.
authors.forename: Georgina
authors.initials: G
authors.lastname: Alarcón-Angeles
mesh_terms: D001205:Ascorbic Acid / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D004563:Electrochemistry; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D007103:Immobilization; D010084:Oxidation-Reduction; D013499:Surface Properties; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D047392:beta-Cyclodextrins; D002244:Carbon; C031215:betadex; D001205:Ascorbic Acid