Synthesis of a new triazene reagent and its application for the determination of silver(I) by the Rayleigh light-scattering

A new triazene group reagent m-nitrophenylazo-2-aminothiazole (m-NPAAT) was first synthesized and characterized by elemental analysis, and H-1-NMR and IR spectra. This new reagent reacts with Ag(I) in a slightly basic medium to form an 1:1 complex, which exhibits intensive resonance-enhanced Rayleig h light-scattering (RLS) in the presence of Tween-20. A new method for the determination of Ag(I) by RLS based on this reaction is proposed. The inten sity of the RLS at 456 nm is proportional to silver(I) concentration in the range of 1.0-700 mu g l(-1) with a detection limit of 0.5 mu g l(-1) Expec t for I-, SCN- and Pd-II, no other ions interfere in the determination at 5 -1000 times the concentration of Ag(I). The method is thus sensitive and of good selectivity, and has been used for the determination of trace impurit y silver in an anti-cancer drug and in chemical samples and for the measure ment of the solubility product of silver chloride. (C) 1999 Elsevier Scienc e B.V. All rights reserved.