Feasibility of tetracycline, a common antibiotic, as chelating agent for spectrophotometric determination of UO22+ after cloud point extraction

Abstract

A cloud point extraction (CPE) procedure was presented for the preconcentration of UO22+ ion in different water samples. Tetracycline (TC) is the second most widely used antibiotics in the world and is used as chelating agent. To the best of our knowledge, this is the first work that an antibiotic is used as a chelating agent for CPE of UO22+. Besides, the use of TC as complexing agent provides excellent chelating features. TC molecule has large numbers of functional groups (adjacent hydroxyl oxygen atoms and cyclohexanone oxygen atoms, amide groups) which can form stable complex with UO22+. After complexation with TC, UO22+ ions were quantitatively recovered in Triton X-100 after cooling in the ice bath. 3.0 mL of acetate buffer was added to the surfactant-rich phase prior to its analysis by UV-Vis spectrophotometer. The influence of analytical parameters including pH, buffer volume, TC, Triton X-100 concentrations, bath temperature, incubation time were optimized. The effect of the matrix ions on the recovery of UO22+ ions was investigated. The limit of detection was 0.0746 mu g mL(-1) along with enrichment factor of 14.3 with a R. S. D. of 3.6 %. The proposed procedure was applied to the analysis of various environmental water samples. On the other hand, the electronic distribution of TC molecule is investigated with their frontier molecular orbital density distributions.