Spectrophotometric determination of silver with 2-(2-quinolylazo)-5-diethylaminophenol as chromogenic reagent

A new chromogenic reagent, 2-(2-quinolylazo)-5-diethylaminophenol (QADEAP) was synthesized. A highly sensitive, selective and rapid method for the determination of silver based on the rapid reaction of silver(I) with QADEAP has been developed. In the presence of citric acid-sodium hydroxide buffer solution (pH=5.0) and sodium dodecyl sulfonate (SDS) medium, QADEAP reacts with silver to form a violet complex of a molar ratio 1:2 (silver to QADEAP). The molar absorptivity of the complex is 1.33x10(5) L mol(-1) cm(-1)at 590 nm. Beer' s law is obeyed in the range of 0.01-0.6 micro g mL(-1). The relative standard deviations for eleven replicate samples of 0.2 microg mL(-1) is 1.38%. This method was applied to the determination of silver in water with satisfactory results.