Determination of Aluminum Ion with Morin in a Medium Comprised by Ionic Liquid–Water Mixtures

Abstract

In this study we have employed two ionic liquids (ILs) as a new media for the analysis of aluminum in aqueous solutions by spectrofluorimetric method. ILs are liquid salts and they have no measurable vapor pressure up to their thermal decomposition point, >300 °C. This lack of vapor pressure makes these materials highly attractive for many studies as they can be used as clean solvents. Besides they are promising environments for analysis purposes and optical sensor designs. The results revealed that absorption, excitation and emission spectra of the morin-Al complex exhibited considerable changes in moieties. The morin-Al complex was stable at aluminum concentrations below 9.1 mg L(-1) in 25% 1-butyl-3-methylimidazolium bromide (IL-I)-water binary mixtures. The higher concentrations of IL (>25% by volume) was not suitable for the complex formation thus in pure IL media the complex formation even at high aluminum concentrations was not observed. The complex stoichiometry ratio of aluminum:morin was 2:1 in IL-I-water binary mixtures. The linear concentration range was 0.045-7.2 mg L(-1) with a correlation coefficient of r = 0.9909. The detection limit was found to be 0.036 mg L(-1). Cu(2+), Mn(2+) and PO (4) (3-) ions exhibited less interfering effect in presence of IL-I and the tolerance limit of Cu enhanced 10 times when compared with ethanol.