Fluorescence Reaction of 5- (p-Methoxyphenylazo)-8-(p-tolylsulfonamido)quinoline with Cobalt(II) and Its Analytical Application

5-(p-Methoxyphenylazo)-8-(p-tolylsulfonamido) quinoline(MTAQ) has been synthesized. The product was checked by IR, theroograviae-try, NMR and elemental analysis. A highly sensitive spectrofluorim-etric method has been developed for the determination of cobalt(II) based on the formation of a complex with MTAQ in slightly basic medium aqueous solution and In the presence of nonionic surfactant, tween-80. The complex shows two excitation maxima at 304 nm and 338 nm, its emission maximum is centred at 402 nm. The fluorescence intensity is proportional to cobalt(II) concentration in the range of 0-85 ppb. The method has good selectivity and has been applied to the direct fluorimetric determination of trace cobalt(II) in pig's liver, Dianchi shrimp and celery.