Khedr, A. M.Gaber, M.Issa, R. M.Erten, H.2016-02-082016-02-0820050143-7208http://hdl.handle.net/11693/23967The new azo compound 5-[3-(1,2,4-triazolyl-azo]-2, 4-dihydroxy-benzaldehyde (TA) and its Schiff bases with 1,3-diaminopropane (TAAP) and 1,6-diaminohexane (TAAH) have been synthesized. The bands of diagnostic importance in the IR and the main signals in 1H NMR spectra are assigned. The electronic absorption spectra in pure organic solvents of different polarity and in buffer solutions of varying pH are investigated. The quantitative description of the solvent effect on the electronic absorption spectra is studied and their acid ionization constants are determined. Also, a new simple and sensitive method for the spectrophotometric microdetermination of Co(II) using these compounds (TA, TAAP and TAAH) as new chromogenic reagents is established. The developed method is successfully used for the determination of trace amounts of cobalt in authentic samples and calculation of the distribution ratio of cobalt adsorbed on bentonite and kaolinite clay minerals. © 2004 Elsevier Ltd. All rights reserved.EnglishAzodyesCobaltSpectrophotometric determinationTriazoleArticle10.1016/j.dyepig.2004.11.004