Analytical Sciences

Abstract − Analytical Sciences, 19(2), 299 (2003).

Solid Phase Extraction and Spectrophotometric Determination of Silver with 2-(2-Quinolylazo)-5-diethylaminophenol as Chromogenic Reagent
Guangyu YANG,  Qiufen HU, Jihong YANG, Zhangjie HUANG, and Jiayuan YIN
Department of Chemistry, Yunnan University, Kunming 650091, P. R. China
A new chromogenic reagent, 2-(2-quinolylazo)-5-diethylaminophenol (QADEAP), was synthesized. A sensitive, selective and rapid method has been developed for the determination of ug/L level silver ion based on the rapid reaction of silver(I) with QADEAP and the solid phase extraction of the colored chelate with C18 cartridge. The QADEAP reacts with Ag(I) to form a violet chelate of a molar ratio 1:2 (silver to QADEAP) in pH 3.5 - 8.0. This chelate was prconcentrated by solid phase extraction with C18 cartridge. An enrichment factor of 100 was achieved. The molar absorptivity of the chelate is 1.30 x 105 L mol-1 cm-1 at 590 nm in measured solution. Beer's law is obeyed in the range of 0.01 - 0.6 ug/ml. The relative standard deviation for eleven replicate samples of 0.01 ug/ml is 1.15%. The detection limit is 0.02 ug/L in the original samples. This method was applied to the determination of ug/L level silver ion in water with good results.