Abstract
A sensitive and selective spectrophotometric determination of silver(I) based on an association complex between silveradenine and eosin was established. The apparent molar absorptivity of the complex, without solvent extraction, was 1.1×105dm3 mol-1 cm-1 at 560nm. No metal ion interfered in an equimolar ratio of silver(I) among the metal ions examined. The method was applied to assays of silver in silver solder and silver protein: the results were in good agreement with those obtained by ICP-AES. The sensitivity could be further enhanced about 5-10 times over that of spectrophotometry with the third-derivative spectrophotometry and/or the fluorescence quenching method. Thermodynamic parameters (ΔG=-6.34kcal mol-1, ΔH=-28.17kcal mol-1 and ΔS=-72.73cal mol-1 K-1) and the binding parameters (n=0.98 and K=4.10×104M-1 at 27°C) suggest that colored complex formed in this reaction system is an association complex between silver-adenine and eosin.
