title: Silver-ion redox sensing based on colloid formation by gallate ester derivatives.
abstract: Plasmon absorption of silver colloid, which was formed by reduction of silver ion with compounds bearing gallate ester groups in ethanol, was observed by absorption spectroscopy. The time-dependent absorption of silver colloid was found, which shows that the silver colloid is unstable and easy to aggregate. It seemed that a calixarene derivative bearing two gallate ester groups was the most suitable for determining silver ion. In order to prevent the silver colloid aggregation, poly(N-vinylpyrrolidone) (PVP) was added into the solution at a constant time after the preparation of sample solutions. In the calibration graph, the absorbance increased with increasing silver ion concentration, especially in the concentration range of 2.00 x 10(-6) to 1.00 x 10(-5) M. It is possible to determine silver ion concentrations using this method.
authors.affiliation: Faculty of Systems Engineering, Wakayama University, Sakae-dani 930, Wakayama 640-8510, Japan.
authors.forename: Setsuko
authors.initials: S
authors.lastname: Yajima
authors.forename: Yoshie
authors.initials: Y
authors.lastname: Iwane
authors.forename: Eisaku
authors.initials: E
authors.lastname: Nomura
authors.forename: Hisaji
authors.initials: H
authors.lastname: Taniguchi
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kimura