Silver(I)-gelatin interaction: spectrophotometric determination of trace amounts of silver in water

Abstract

A simple, selective and sensitive spectrophotometric method for the determination of silver(I) in water at levels up to 10 µg ml^–1 is presented. The method is based on the reduction of the colourless silver-gelatin complex to give a red silver sol (λ_max.= 415 nm, ε= 1.075 × 10⁴ l mol^–1 cm^–1) in alkaline medium. The method is used for the determination of silver ion in effluent water and photographic papers. The characteristics and reactions of the silver-gelatin complex with various reducing agents are also presented. The sensitivity for an absorbance of 0.001, relative standard deviation and confidence limit (95%) for 5.40 µg of silver (40 replicates) are 1.0034 × 10^–2µg cm^–2, 1.4% and 5.385 ± 0.024, respectively.