Spectrophotometric Determination of Iodide Ion Based on the Color Fading Reaction of the Ion Association Complex of Adenin Silver(I) Ion and Eosin

Abstract

A novel spectrophotometric method was established for the determination of iodide ion and organic iodine compounds. The method is based on a color-fading reaction of the ion-association complex of adenin silver(I) ion and eosin. In the determination of iodide ion, Beer's law was obeyed in the range of 0.04∼1.3 μg mL⁻¹. The apparent molar absorptivity at 560 nm and the relative standard deviation were 1.38 × 10⁵ dm³ mol⁻¹ cm⁻¹ and 2.34% (n = 5), respectively. The proposed method, which requires no pretreatments, should be useful for a simple and sensitive determination of iodide ion. In addition, this method could be applied to organic iodine compounds.