Determination of trace amounts of silver(I) in the presence of an activator with a kinetic method

摘要

A simple and sensitive kinetic-spectrophotometric method was developed for the determination of trace amounts of silver, based on its catalytic effect on the oxidation of azocarmine G by peroxydisulfate in sulfuric acid medium and at 30 °C in the presence of 1,10-phenantroline as activator. The absorbance was measured at 525 nm with the fixed-time method. The optimization of the operating conditions regarding concentrations of the reagents, temperature, ionic strength, and interferences was also investigated. The calibration curve is linear over the concentration range 0.3–50.0 ng ml-1of silver with good precision and accuracy, and the detection limit is down to0.125 ng ml-1. The relative standard deviation for a standard solution of 25.0 ng ml-1of silver is 1.36 %(n = 10).The proposed method proves to be highly sensitive,selective, and relatively rapid for the assay of silver at lowlevel range of 0.3–50.0 ng ml-1without any pre-concentration and separation step. The method was applied for the determination of silver in river water and white photographic film. The analytic results of the real samples are in excellent agreement with atomic absorption spectrometry analysis. The analytical results obtained are satisfactory.