Spectrofluorimetric determination of aluminium using 2-hydroxy-1- naphthylidene-(8-aminoquinoline)

A sensitive and selective spectrofluorimetric method has been developed for the rapid determination of aluminium. This method is based on the complex formation between aluminium and 2-hydroxy-1-naphthylidene-(8-aminoquinoline) (HNAQ). The optimum conditions for the complex formation were a metal-to-ligand (M : L) stoichiometric ratio of 1:1, a pH of 5.5 and a 0.20 m acetate buffer. The fluorescence of the complex was monitored at an emission wavelength of 502 nm with excitation at 438 nm. Under these conditions, linear calibration curves were obtained in the ranges 0.05-1 and 1-5 ppm. The detection limit was 3.4 ppb for the former and 13.5 ppb for the latter. The maximum relative standard deviation of the method for an aluminium standard of 200 ppb was 1.5% (n = 5). This method was successfully applied for the determination of aluminium in drinking water, pharmaceutical antacid tablets and suspension samples.