Fluorescence Reactions of “Crowned” Benzothiazolylphenols with Alkali and Alkaline Earth Metal Ions and Their Analytical Applications

Abstract

Abstract The fluorescence behavior by a complexation of “crowned” benzothiazolylphenols (CBTP and CBBTP) with alkali and alkaline earth metal ions in the presence of triethylamine was examined in various organic solvents. The fluorescence spectra of these CBTP– and CBBTP–metal ion complexes were measured in order to compare mutually both their excitation and emission maxima together with the relative fluorescence intensities (RFI). Both the Li–CBTP and Li–CBBTP complexes showed considerably higher RFI than the other metal complexes. The stability of the fluorescence intensity and various conditions for the determination of Li+ or Ca2+ were fully examined. On the basis of these experiments, fluorometric methods were developed for a sensitive determination of trace amounts of Li or Ca by using the crown compounds (CBTP and/or CBBTP). Moreover, a thin-layer chromatographic method for the separation of Li from other metal ions was examined in order to selectively determine Li by using CBBTP.