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تقدير بعض العناصر الثقيلة في نماذج حقيقية باستعمال مركبات ازو - ازوميثين جديدة بواسطة استخلاص نقطة الغيمة == Determination Of Some Heavy Metals In Real Samples Using New Azo - Azomethine Compounds By CPE
Author name:
ساجدة صبار عفات
Supervisor name:
ساهر عبد الرضا علي الشمخاوي
General topic:
Chemistry
Specific topic:
Analytical Biochemistry
Degree:
Doctorate
University:
University of Thi-Qar - College Of Science - Chemistry Department
Language:
English
University location:
Dhi Qar
Abstract:
Since its inception in 1985, Cloud-point extraction (CPE) methodology has constituted an important theme in the analytical chemistry as promising procedure for the separation and preconcentration for the metal ions and organic compounds from the complex matrices samples. Nowadays, it has been begins to take a large noteworthy position among the other modern separation methods in scientific research and application on a high level due to its simplicity, rapidity, more precise and cheapness beside an environmentally-friendly method, therefore, this research includes three main chapters . | Chapter One includes introduction of azo-azomethine compounds and their complexes and a view of the different extraction techniques, fundamental principles and potential applications of CPE methodology in analytical chemistry. It also involves a concise review on the latest developments of the method and its applications for the determination of cadmium, copper and cobalt by CPE . | Chapter Two consists of an outline of different instrumental techniques , general apparatus and chemicals used in the present work. | The synthesis paths of azo-azomethine compounds (L1 to L4) and primary testing of complex formation between metal ions and reagents, determination of λmax . As well as optimization of the experimental conditions (volume reagent, reaction time, temperature and pH) and determination of dissociation degree and stability constant, stoichiometry of the complex (Continuous variation method -Job method). In addition CoCl2.6H2O and L4 with salts CrCl3.6HO and CdCl2.H2O. The analytical | procedures for CPE which were designed for the determination of analytes including optimization of the Parameters for CPE including (reagent concentration, HCl concentration, incubation time, equilibration temperature, thermodynamic study and Triton X-100 volume) were selected in this study. The present CPE method was applied for determination concentration of metal ions (Cd2+, Cu2+ and Co2+) in real samples by FAAS. | Chapter Three included the new azo-azomethine compounds prepared and their complexes which were characterized by various analytical techniques as a UV-Visible spectroscopy(UV-Vis), Infrared Spectroscopy(FT-IR), Nuclear Magnetic Resonance Spectroscopy(1HNMR), Mass Spectra and Molar Electrical Conductivity for complexes and the results were identical to what is expected scientifically. The spatial shape of the complexes which was prepared is (octahedral) and stoichiometry of the complex. It’s ratio 1 : 1. | In chapter three, there are too highlights on the results and discussion in analytical applications for the separation and preconcentration for the metal with separation and extraction method, such as cloud-point extraction (CPE) as an separation technique that uses a surfactant, instead of organic solvents for phase separation. | In the first part of CPE, Analytical reagent namely 6-((1E)-((2-(((E)-2-hydroxy-3-methoxy-4-((6-methoxybenzo[d]thiazol-2- yl)diaz enyl)benzylidene)amino)benzyl)imino)methyl)-2-methoxy-3- ((6- methoxybenzo[d]thiazol-2-yl)diazenyl)phenol (L1) after synthesis and characterization by using various analytical techniques as a preliminary using various analytical techniques as a preliminary step toward its using | as an organic reagent for the formation of an ion-association complex | with copper ion in acidic medium, apt to interact with surfactant in | solution. The L2 as a reagent for the formation of an ion association | complex with copper in acidic solution and the complex is extracted into | the surfactant Triton X-100 at optimum conditions. The surfactant-rich | phase which contains copper complex is mediated with solvent and the | Cu content measured by FAAS (λmax = 324.75 nm) . The effects of the several variables which affect the CPE efficiency are optimized by OFAT procedure beside other parameters with which one is mentioned with Cu(II) . The thermodynamic study was also investigated to expand the understanding of the mechanism of solvation of Cu(II) in the micelles . | Under the optimized condition established, the enrichment factor of 52.574 was achieved for Cu2+ with the L2 . The concentration range of (0.01-3) μg ml-1 leads to detection limit of 0.017238 μg ml-1. The precision for ((%RSD, n=8) at 0.05μg.ml-1 Cu2+ was of %1.063. The developed method was used for the determination concentration of Cu2+ in real samples. The accuracy was determined by recovery percentage for real samples, it’s found good recoveries (100.380-103.377%) for Cu2+ with L2. | In the third part CPE, Analytical reagent namely6-(((2-(((E)-2- hydroxy-3-methoxy-4-(o-tolyldiazenyl)benzylidene)amino) benzyl)imino)methyl)-2-methoxy-3-(o-tolyldiazenyl)phenol(L3)was synthesised and fully characterized by using various analytical techniques | as a preliminary step toward its using as an organic reagent for the formation of an ion-association complex with cobalt ion in acidic medium and the complex is extracted into the surfactant Triton X-100 at optimum conditions for determination of Co(II) as CoCl4 | 2- ion by using the combined cloud point extraction (CPE) methodology. After phas separation, the surfactant-rich phase was diluted with 1M HNO3 in methanol and cobalt (II) ion determined by FAAS technique at λmax of 240.72 nm. The optimization of complexation and extraction conditions was investigated. Thermodynamic parameters of CPE for solubilization process of the ion-pair complex in Triton X-100 were also considered. | Under the optimized conditions, the preconcentration of a 15ml sample which gave preconcentration and enrichment factors were of 15 and 54.078 respectively. The calibration graph was linear in the range of (0.025-3) μg ml-1 with a limit of detection and quantitation limit 0.011534 and 0.038446 μg ml−1. The relative standard deviation for replicate determinations at 0.05μg ml−1 level was of (0.823%, n=8). The proposed | method was applied for the determination of cobalt in river, tap waters, milk, black tea , tobacco and soil by FAAS. The accuracy was determined by recovery percentage for real samples, it’s found good recoveries (101.108-104.918%) for Co2+ with L3 . The study of the stoichiometry for ion association complexes using the slope analysis technique showed that the ion association complex ratio was 1 : 1 for all extracted complexes
