Evaluation of N-Alkyl-bis-o-aminobenzamide Receptors for the Determination and Separation of Metal Ions by Fluorescence, UV-Visible Spectrometry and Zeta Potential.

This paper presents the synthesis and evaluation of physicochemical behavior of a new series of N-alkyl-bis-o-aminobenzamides (BOABs) in aqueous solution. The study was targeted to the complexing capacity of five metal ions (Fe2+, Cu2+, Cd2+, Hg2+ and Pb2+) of environmental concern as the medullar principle of a liquid phase sensor for its application in the determination of these metal ions due to its versatility of use. Molecular fluorescence, UV-visible and Zeta potential were measured for five BOABs and the effect of alkyl groups with different central chain length (n = 3, 4, 6, 8 and 10) on physicochemical performance determined. The results have shown that these derivatives present higher sensibility and selectivity for Cu2+ even in the presence of the other metal ions. An additional application test was done adding a pectin (0.1 wt %) solution to the BOAB-Cu+2 complex to obtain a precipitate (flocs) as a potential selective separation process of Cu from aqueous solution. The solid was then lyophilized and analyzed by SEM-EDS, the images showed spheric forms containing Cu+2 with diameter of approximately of 8 μm and 30 wt %.