Fluorescence reaction of sodium 7-phenylazo-8-aminoquinoline-5-sulphonate with gold and its analytical application

Abstract

Sodium 7-phenylazo-8-aminoquinoline-5-sulphonate has been synthesized and its identity confirmed by infrared spectrometry, thermogravimetry and elemental analysis. This compound reacts with gold(III) in slightly acidic media forming a red complex which has an intense fluorescence at λ_em/λ_ex= 380 nm/325 nm. The fluorescence intensity is proportional to the concentration of gold(III) in the range 0–320 ppb with a detection limit of 0.5 ppb. The method has been used for the determination of trace amounts of gold in mines.