Spectrophotometric Method for the Determination of Silver Using 2,2',3,4-Tetrahidroksy-3'-Sulfo-5'-Nitroazobenzene

Abstract

A fairly simple, selective and non-extractive spectrophotometric method for the determination of trace amounts of silver (I) was developed and 2,2 ' ,3, suggested as a new analytical reagent for the direct non-extractive spectrophotometric determination of silver (I). In the aqueous medium TSNAB reacts with silver to give a highly orange absorbent chelate with a molar ratio of 1:2 (Ag: TSNAB). Note that the reaction is instantaneous and the maximum absorption was obtained at 490 nm that remains stable for 24 h. The average molar absorptivity and Sandell's sensitivity were found to be 1.37×10 4 l mol -1 cm -1 and 8.0 mkg cm -2 of silver(I) respectively. Linear calibration graphs were obtained for 0.864-5.184mkgml −1 of silver(I). A large excess of over 30 cations, anions and complexing agents impedes no determination. The non-extractive method is rather selective for silver(I) to have been successfully applied to synthetic mixtures.