Abstract:

With the aid of combining 3,3′,5,5′-tetramethylbiphenyl with benzothiazole through triazene group, a new fluorescent reagent bis(2-benzothiazolydiazoamino)3,3′,5,5′-tetramethylbiphenyl(BBTDTMB) was synthesized. The product was confirmed by means of elemental analysis, 1H NMR and infrared spectra. Its excitation and emission wavelengths were 342 nm and 420 nm in a basic medium, respectively. This new reagent reacts with Ag(Ⅰ) in a slightly basic medium to form a 1∶2 complex, by which silver ion causes the fluorescence quenching of the new fluoresent reagent. The reaction showed a high selectivity and a high sensitivity for Ag(Ⅰ). A new spectrofluorimetric method for the determination of trace Ag(Ⅰ) with this reagent was developed. The linear range of determination for Ag(Ⅰ) was 1.0—240 μg/L with a detection limit of 0.5 μg/L. The method is a selective, sensitive, and simple analytical procedure, and was used for the determination of trace Ag(Ⅰ) in hair and tea with satisfactory results.

Key words: Bis(2-benzothiazolydiazoamino)3,3′,5,5′-tetramethylbiphenyl; Fluorescence quenching; Silver detection