title: Voltammetric detection of inorganic phosphate using ion-channel sensing with self-assembled monolayers of a hydrogen bond-forming receptor.
abstract: A voltammetric ion-channel sensing for phosphate based on gold electrodes modified with the self-assembled monolayers of a bis-thiourea receptor was developed to detect phosphate. The working principle of this voltammetric sensor conceptually mimics that of ligand gated ion-channel proteins, as to chemically stimulated changes in membrane permeability. The response to analytes is based on the change in electron transfer rate constant of the redox reaction of [Fe(CN)(6)](4-/3-) marker, before and after binding of phosphate to the receptor on the electrode surface; where the electrostatic repulsion between a phosphate-receptor complex and the marker induced the decrease in the rate constant. In a solution of pH 7.0, a high selectivity was observed for phosphate and the sensor was virtually insensitive at all to many of other anions, such as SO(4)(2-), AcO(-), NO(3)(-), and Cl(-). The sensor response was obtained with phosphate concentrations above 5.0 x 10(-4) M using cyclic voltammetry and differential pulse voltammetry.
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo, Hongo, Tokyo 113-0033, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Aoki
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Hasegawa
authors.forename: Koji
authors.initials: K
authors.lastname: Tohda
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Umezawa
mesh_terms: D020099:Coated Materials, Biocompatible / Q000138:chemical synthesis*; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D005295:Ferrocyanides; D007473:Ion Channels / Q000032:analysis / Q000737:chemistry; D010084:Oxidation-Reduction; D010710:Phosphates / Q000032:analysis* / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013890:Thiourea
chemical_list: D020099:Coated Materials, Biocompatible; D005295:Ferrocyanides; D007473:Ion Channels; D010710:Phosphates; C020354:hexacyanoferrate II; D013890:Thiourea