Browsing by Author "Varbanov M."

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    Complex activity and sensor potential toward metal ions in environmental water samples of n-phthalimide azo-azomethine dyes
    (2021-10-01) Georgieva S.; Bezfamilnyi A.; Georgiev A.; Varbanov M.
    Herein, the spectral and electrochemical characterizations of three different substituted N-phthalimide azo-azomethine (NAA) dyes (L) containing an o-hydroxy group and their NAA-M(II) chelates [M(II): Cu, Ni, Co, Pb] were reported by using UV–Vis and fluorescence spectroscopy and potentiometric and voltamperometric techniques. The pK value of the dyes as well as the stoichiometry and stability of the NAA-metal chelates were studied, and the stoichiometry was found to be mostly 1:2 (ML2 ) with high complex stability constant values. The sensor activity of N-phthalimide azo-azomethine derivatives toward pH and metal ions has been also investigated and tested for indicator application in acid–base analysis and detection of Cu(II) ions in real samples of surface river water using voltamperometric detection. The results showed that one of the ligands possesses the highest electrochemical response upon binding to copper ions and could be successfully used in the analysis of copper in water at a concentration range of the analyte from 3.7 × 10−7 to 5.0 × 10−6 mol L−1, with analytical characteristics of the method being Sr = 1.5%, LOD = 3.58 µg L−1 and LOQ =11.9 µg L−1.
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    Territorial features and dynamics in the water quality change in the Topolnitsa and Luda Yana rivers
    (2020-01-01) Gartsiyanova K.; Varbanov M.; Kitev A.; Genchev S.; Georgieva S.
    In this article the current changes in the water quality of rivers Topolnitsa and Luda Yana have been analyzed and evaluated. The river basins are under the significant anthropogenic impact of various origins and nature. The main sources of pollution, the emitted substances and the spatio-temporal features of the change of the water quality are determined. Several indices for complex assessment of river waters have been used to assess the status of water-(Water Quality Index-Canada; Water Pollution Index-Russia; Chemical Index for River Water Quality (CJ)-Germany).