Flow injection determination of silver with spectrophotometric detection

A flow injection system is proposed for the rapid and sensitive determination of trace concentrations of silver(I) based on its catalytic effect on the oxidation of gallocyanine by peroxodisulphate in the presence of 1,10-phenanthroline as an activator with spectrophotometric detection. Silver can be determined in the range of 0.002-0.700 mu g with a limit of detection of 0.001 mu g. The relative standard deviation for ten replicate determinations of 0.035 and 0.170 mu g of Ag(I) was 2.8% and 0.9%, respectively. The method was successfully applied to the determination of silver in real samples.