الفهرس 
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Abstract
The present thesis is composed of three chapters; each chapter can be summarized as follow:
Chapter 1: Introduction
The main point that have discussed through this chapter can be summarized as follow:
a- General introduction about the heavy metals, its toxicity and the effects of these metals on living organisms.
b- The several methods used for separation and pre-concentration of different metal ions prior to their determination such as co- precipitation, solid phase extraction, ion exchange resins, flotation, liquid-liquid extraction and cloud point extraction.
c- The detailed survey on the phase separation in cloud point extraction and its advantages as a promising, viable and benign alternative to the current classical separation method such as, simplicity, cost saving, speed, high pre-concentration factor and no waste generation as practiced in the liquid extraction tools.
d- The different types of surfactants which used in cloud point extraction.
e- Formation of micelles and their different forms.
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f- The different parameters affecting on the extraction efficiency of cloud point extraction system including pH, chelating agent, concentration and type of surfactant, temperature, equilibration time and ionic strength.
g- The different types of ligands which previously used in cloud point extraction.
h- The applications of cloud point extraction for separation and pre- concentration of different analytes such as, organic compounds, biomaterials, nanoparticles and metal ions.
Chapter 2: Experimental
Includes a list of reagents, stock solutions along with the analysis, physical measurements and instruments (IR, UV-Vis, 1H-NMR, MS, magnetic and thermal).
As well as adscription of the preparation of the ligand and its metal complexes , studding the different parameters for the optimization of CPE procedure, pre-treatment of real samples and applications of the proposed method for separation, pre-concentration and determination of metal ions from different media (geological and water samples, simulated reference material, synthetic mixtures).
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Chapter 3: Results and discussion
It divided into 5main parts.
Part (1): A Micro Mixed Micelle-mediated Preconcentration Procedure for Spectrophotometric Determination of Uranium in Real and Synthetic Samples.
The absorption spectra of SPADNS and Uranium –SPADNS complex was investigated at514 and 538 nm.
The main factors affecting mixed micelle-mediated extraction efficiency were studied and optimized as follow:
A pH 7 was chosen as the optimum pH for separation and determination of Uranium.
The optimum condition of SPADNS concentration was 5.0×10-5 mol L-1.
1.0×10-4 mol L-1 concentration of CTAB was used as optimal.
The optimum condition of Triton X-114 concentration was 0.07 % (v/v) during the study.
The effect of the addition of various salts (NaCl, KI, and Na2SO4) on the recovery of U6+ by the under-investigated method was
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studied and the results showed that the addition of Na2SO4 provided a higher recovery for U6+ than the NaCl and KI.
The best centrifugation rate at 4000 rpm and time at 5 min.
Effect of the potentially interfering ions was summarized as ; most species did not interfere even at high concentrations, indicating the applicability of the method for analysis of U6+ in samples with different matrices. However, Al3+, Cu2+ and Zr4+ showed interferences at 100 folds higher. These interferences can be eliminated by addition of 0.1% (w/v) EDTA.
At optimum conditions, the linear range was 5- 3000 μg L-1 with a detection limit of 1.05 μg L-1 was achieved for uranium separation using visible spectrophotometry. The accuracy of the procedure was verified through recovery experiments in water, geological and simulated high level waste samples and the % recovery is between 95.0-99.2%.
Part (2): Determination of trace Al3+ by CPE using SPADNS as a chelating agent.
The absorption spectra of SPADNS and Al3+-SPADNS complex was investigated at 512 and 590 nm.
The main factors affecting cloud point extraction efficiency were studied and optimized as follow:
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A pH 5 was chosen as the optimum pH for separation and determination of Al3+.
The optimum condition of SPADNS concentration was5.0×10-5 mol L-1 .
1.0×10-4 mol L-1 concentration of CTAB was used as optimal.
The optimum condition of Triton X-114 concentration was 0.05 % (v/v) during the study.
The effect of the addition of various salts (NaCl, KI, KNO3 and Na2SO4) on the recovery of Al3+by the under-investigated method was studied and the results showed that the addition of Na2SO4 provided a higher recovery for U6+ than the NaCl , KI and KNO3.
The best centrifugation rate at 4000 rpm and time at 5 min.
Effect of the potentially interfering ions was summarized as ; most species did not interfere even at high concentrations, indicating the applicability of the method for analysis of Al3+in samples with different matrices. However, U+6, Cu2+ and Zr4+ showed that interferences at a concentration of 200 times higher than Al3+ concentration. The interferences of U+6, Cu2+ and Zr4+ can be eliminated by addition of 0.1% (w/v) EDTA.
At optimum conditions, the linear range was 5- 500 μg L-1 with a detection limit of 1.5 μg mL-1 was achieved for Al3+separation using visible spectrophotometry. The accuracy of the procedure
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was verified through recovery experiments in water, blood, rocks and soil samples and the % recovery is between 95.0-98.6%.
Part (3): Determination of copper in biological and geological samples by CPE using SPADNS as a ligand and FAAS as an analyzing technique.
The absorption spectra of SPADNS and Copper–SPADNS complex were investigated at 512 and 570nm.
The main factors affecting cloud point extraction efficiency were studied and optimized as follow:
The optimum pH for separation and determination of Cu2+ was chosen as pH 7.
The optimum condition of SPADNS concentration was 1.0×10−4 mol L-1 .
The optimum concentration of CTAB was used at a 1.0×10-4 mol L-1.
The optimum condition of Triton X-114 concentration was 0.05 % (v/v) during the study.
The effect of the addition of various salts such as (KI, KNO3, NaCl and Na2SO4) on the recovery of Cu2+by the under-investigated method was studied and the results showed that the addition of Na2SO4 resulted a higher recovery for Cu2+than the NaCl, KI and KNO3.
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The best centrifugation rate at 4000 rpm and time at 10 min.
Effect of the potentially interfering ions was summarized as follow ; most species did not interfere even at high concentrations, indicating the applicability of the method for analysis of Cu2+in samples with different matrices. However, U6+and Al3+ showed interferences at 250 folds higher and Zr4+ showed interferences at 400 folds higher. These interferences can be eliminated by addition of 0.1% (w/v) EDTA.
At optimum conditions, the linear range was 5-1000 μg L-1 with a detection limit of 1.45 μg L-1 was achieved for Cu2+separation using visible spectrophotometry. The accuracy of the procedure was verified through recovery experiments in water, blood, rocks and soil samples and the % recovery is between 98.5-100%.
Part (4): Spectrophotometric determination of zirconium by CPE using SPADNS as a ligand.
The addition of Zr4+to SPADNS results in a color change due to the formation of Zr-SPADNS complex with a maximum absorbance at 587 nm.
Optimization of the CPE procedure f determination of zirconium as follow;
The maximum absorbance was obtained at pH 2.0. So pH 2.0 was selected for the subsequent studies.
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The optimum concentration of SPADNS was 1.0×10-4 for the determination of Zr (IV).
The concentration of Triton X-114 was used as optimal is at 0.05 % (v/v).
The optimum concentration of CTAB was0.5×10-4 mol L-1 .
At 45˚C was chosen for the equilibration temperature and incubation time of 10 min is adequate to achieve the highest extraction efficiency.
A centrifugation time of 5.0 min was selected and the rate of centrifugation was 4000 rpm.
Effect of the addition of different salts on the recovery of Zr4+showed that the addition of Na2SO4 provided a higher recovery for Zr4+than the NaCl and KI.
The presence of large amounts of commonly occurring cations and anions as well as some masking agents has no obvious influence on the separation and determination of Zr4+under the optimum work condition, Al3+ showed interferences at 150 folds higher and U6+ showed interferences at 100 folds higher. These interferences can be eliminated by addition of 0.1% (w/v) EDTA.
At optimum conditions, the linear range was 5- 3000 μg L-1 with a detection limit of 0.88 μg L-1 was achieved for Zr4+separation using visible spectrophotometry.
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Part (5): A new thiourea derivative [2-(3-ethylthioureido) benzoic acid (ETB)] for CPE of Fe3+, Co2+, Cu2+ and Zn2+prior to their determination by FAAS.
We present here the synthesis of 2-(3-ethylthioureido)benzoic acid (ETB) as a new thiourea derivative and its use in the preconcentration of Fe3+, Co2+, Cu2+ and Zn2+ in aqueous medium by CPE in the presence of Triton X-114 as extractant.
characterization of ETB such as Elemental analyses and Mass spectrum, FT-IR spectrum and 1H-NMR spectrum.
Optimization of the CPE procedure as follow :
PH 7 was used for the all metal ions (Fe3+, Co2+, Cu2+ and Zn2+).
The optimum concentration of ETB is 5.0 × 10-5 mol L-1 for the four metals ions.
A concentration of 0.1% (v/v) of Triton X-114 was chosen for following experiments.
The presence of 0.1 mol L-1 of Na2SO4 makes the system cloudy without the need of heating and therefore make the extraction process more rapid and energy saving.
The results for (Fe3+, Co2+, Cu2+ and Zn2+) indicate that centrifugation at 3000 rpm for 5 min recover all studied metal ions quantitatively.
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The stability constants were found to be 7.0 × 105, 2.3 × 105, 1.9 × 106 and 3.2 × 105 L mol−1 for Fe3+, Co2+, Cu2+ and Zn2+, respectively, indicating good stability of the complexes.
The results indicated that most concomitant ions had no interference effects on the determination of Fe3+, Co2+, Cu2+ and Zn2+ by the presented CPE procedure. This indicates the possibility of applying the procedure for analysis of real samples of different matrices.
At optimum conditions, the linear range were 5-500, 0.23-200, 2.4-500, 0.12-500 for Fe3+, Co2+, Cu2+ and Zn2+ respectively and LOD for Fe3+, Co2+, Cu2+ and Zn2+ were 1.5, 0.23, 071. 0.35 respectively.
The reliability of the suggested procedure, it was applied for preconcentration of Fe3+, Co2+, Cu2+ and Zn2+ from real samples such as water samples , blood sample ,urine sample and food samples prior to their determination by FAAS. The recoveries for the addition of different amounts of metal ions to the samples were quantitative (˃95.0%) indicating the accuracy and applicability of the procedure.