RESUMO
A very simple and non-extractive spectrofluorometric method for the swift determination of aluminum at nano-trace levels using 2',3,4',5,7-pentahydroxyflavone (morin) has been developed. Morin reacts in a slightly acidic (0.005 - 0.025 M H2SO4) solution with aluminum in 20% ethanol to produce a highly fluorescent complex in aqueous solution, which has excitation and emission wavelengths of λex = 270 and λem = 565 nm, respectively. Linear calibration graphs were obtained for 0.01 - 800 µg L-1 of Al, providing a detection limit of 1 ng L-1. The limit of quantification of the reaction system was 10 ng L-1. The stoichiometric composition of chelate is 3:2 (Al:morin). The developed method was successfully used in the determination of aluminum in several Standard Reference Materials (SRM) as well as in some water, biological, hemodialysis solutions, food, pharmaceutical, soil sample, and complex synthetic mixtures. The results of the proposed method for biological and food analysis were found to be in excellent agreement with those obtained by AAS. The results of the proposed method for hemodialysis solutions were analogous with those obtained using the method described in British Pharmacopoeia within 95% confidence limits.
