Highly sensitive spectrofluorimetric determination of trace amounts of chromium with 2-hydroxy-1-naphthaldehydene-8-aminoquinoline

A new fluorescent reagent, 2-hydroxy-1-naphthaldehydene-8-aminoquinoline (H NAAQ). was synthesized. The fluorescent reaction of this reagent with chrom ium was studied. Based on this chelation, a highly sensitive spectrofluorim etric method was developed for determination of trace amounts of chromium i n a water-ethanol (4 + 1, v/v) medium at pH = 9.4. Under these conditions, the Cr-HNAAQ complex has excitation and emission maxima at 397 and 450 nm, respectively. The linear range of the method is from 0 to 25 mug l(-1) and detection limit is 77 ng l(-1) of chromium. Interference of other ions was studied. It is necessary to remove the interfering cations through cation e xchange resin. The selectivity of the method can increase obviously. The pr ocedure can be easily performed and affords good precision and accuracy. Th is method has been successfully applied to the determination of chromium in pig liver and pork muscle.