الفهرس | Only 14 pages are availabe for public view |
Abstract Summary This thesis consists of five parts: Part I: General Introduction and literature review: This part consists of two sections: Section A: General Introduction: This part consists of a general introduction on emerging contaminants, their sources, and different types. The different ways by which the selected emerging contaminants reach the environment were described showing their toxic and hazardous effects on all the living organisms. Regulations and intensive legislations to control water quality have been discussed. Finally, Procedures that are needed to be followed in order to overcome and control this hazardous issue have been discussed. Section B: Literature review: This part includes a detailed and thorough review of the selected emerging contaminants, Atenolol, Diclofenac, Carbamazepine and Triclosan. This review compromises the chemical and physical properties, and various analytical methods reported in the literature for their determination. Part II: Spectroscopic methods for the determination of the selected emerging contaminants in drinking tap water samples: This part consists of two sections: Summary xxii Section A: First derivative synchronous spectrofluorimetric method for the simultaneous determination of the binary mixture of atenolol (ATN) and diclofenac (DCF) in drinking tap water samples: In this section, a green, simple, sensitive, and selective first derivative synchronous spectrofluorimetric method was proposed for the simultaneous determination of two emerging contaminants, ATN and DCF, in drinking tap water samples. Combining both the synchronous fluorescence technique and the derivative technique have greatly contributed to the higher sensitivity and selectivity of the proposed method. Furthermore, to achieve an eco-friendly method, solid phase extraction was carried out as a green extraction step in order to minimize the use of toxic organic solvents. The proposed method was validated according to the ICH guidelines and was found to be within the acceptable ranges. The proposed method was successfully applied for the determination of the emerging contaminants in drinking tap water samples with high accuracy, precision, and selectivity. The method was statistically compared with the validated reported methods in the literature and no statistically significant difference was found. Section B: Micellar enhanced spectrofluorimetric method for the determination of triclosan (TCS) in drinking tap water samples: In this work, TCS was detected in drinking tap water samples as an emerging contaminant using a micellar enhanced spectrofluorimetric method. The weak fluorescence of TCS was strongly enhanced using the anionic surfactant sodium dodecyl sulfate as a fluorescent enhancer. Using solid phase extraction as a method of extraction and water as a solvent have greatly contributed to the greenness of the proposed method. Validation of the proposed method was performed according to the ICH guidelines and validation parameters were found to be within the acceptable ranges. Successful determination of the emerging contaminant in drinking tap water samples was achieved with high accuracy, Summary xxiii precision, and selectivity. Statistical comparison between the proposed method and the validated reported method in the literature was performed and no statistically significant difference was found. Part III: Potentiometric methods for the determination of a selected emerging contaminant in different types of environmental drinking water samples: This part consists of two sections: Section A: Three novel microfabricated copper solid-state potentiometric sensors for the determination of an emerging contaminant, triclosan (TCS), in different types of environmental drinking water samples: In this section, three novel microfabricated copper solid-state ion selective potentiometric sensors were proposed for the selective and sensitive determination of TCS in various water samples. Using nanotechnology as an attractive field and macrocyclic compounds with their enhanced supramolecular recognition have successfully enhanced the electrical performance of the developed sensors. Furthermore, the microfabrication of the proposed solid contact ISEs offers several advantages that greatly enhanced the greenness of the proposed method. No need for sample pretreatment and extraction step which is highly recommended for environmental analysis. The performance of the three proposed sensors was evaluated according to the IUPAC recommendations and It was found that they had rapid, stable, and Nernstian response. Response time, influence of pH and temperature on the response, selectivity and stability of the proposed electrodes were studied to determine the optimum conditions for measurements. Comparative study was carried to figure out the most optimum sensor with maximum sensitivity and selectivity. Summary xxiv The method was statistically compared with the validated reported method in the literature and no significant difference was found. Section B: Two novel liquid state potentiometric sensors for the determination of an emerging contaminant, triclosan (TCS), in different types of environmental drinking water samples: This section includes the development of two potentiometric liquid state ion selective electrodes for the selective and sensitive determination of TCS in different water samples. The greenness of electroanalysis has drawn a great attention especially in the field of environmental analysis. Modification of the developed sensors to be applicable for the in-situ environmental monitoring of emerging contaminants in the environment was carried out. Sensitivity and selectivity were greatly enhanced upon modifying the inner filling solution of the developed liquid state electrodes with 2-hydroxy propyl β- cyclodextrin. The developed sensors required no sample pretreatment or extraction step offering the advantage of real time monitoring. The IUPAC recommendations were used to evaluate the performance of the two proposed sensors. Different factors including the response time, pH and temperature were studied and optimized to achieve the optimum conditions for measurements. The two proposed sensors were compared to determine the most optimum sensor with maximum sensitivity and selectivity. Statistical comparison with the validated reported method in the literature were carried out and no significant difference was found. Summary xxv Part IV: chromatographic methods for the determination of the selected emerging contaminants in environmental water samples: This part consists of two sections: Section A: HPLC/DAD method for the determination of a ternary mixture of diclofenac (DCF), carbamazepine (CBZ) and triclosan (TCS) in environmental water samples: In this section, three emerging contaminants, DCF, CBZ and TCS were successfully determined in water samples using an ecofriendly HPLC/DAD method. Separation was carried out on reversed-phase C18 column using photodiode array detector for the simultaneous separation and determination of the studied analytes in environmental water samples using ethanol/water as a mobile phase in an isocratic mode. Ethanol was employed as a benign organic modifier instead of methanol and acetonitrile. The chromatographic conditions were optimized in terms of mobile phase composition and ratio and flow rate. A green extraction step was carried out using solid phase extraction minimizing the use of toxic organic solvents. The proposed method was validated according to the ICH guidelines and was found to be valid. System suitability parameters were calculated and were found to be within the accepted ranges. The method was statistically compared with the validated reported methods in the literature and no significant difference was found. Summary xxvi Section B: UPLC-MS/MS method for the determination of a ternary mixture of atenolol (ATN), diclofenac (DCF) and carbamazepine (CBZ) in Nile river water: In this section, a UPLC-MS/MS method was proposed for the simultaneous determination of ATN, DCF and CBZ in Nile river water samples using acetonitrile/water as a mobile phase in a gradient mode. Samples were collected from a drinking water treatment plant. Shortening the run time to be only 8 minutes and carrying out solid phase extraction as an eco—friendly extraction method have enhanced the proposed method greenness. Matrix effect study showed no significant ionization suppression. Validation of the proposed method was performed according to the ICH guidelines and assay parameters were within the acceptable ranges. The high sensitivity and selectivity of the proposed method have successfully enhanced its application in environmental analysis. Furthermore, the proposed method exhibits high accuracy and precision. No significant difference was found between the proposed method and the validated reported method in the literature upon carrying out a Statistical comparison. Part V: Greenness assessment and General discussion: In this part, owing to the significance of green chemistry and the great interest in implementing green analytical methodologies, greenness assessment of the proposed methods was scientifically performed using two different evaluation tools, Eco-scale, and Green analytical procedure index. Furthermore, comparative study between the greenness of the proposed methods and the reported methods in literature was performed. An overall evaluation of the proposed methods was performed, highlighting the major advantages presented by these methods for each contaminant. A one-way ANOVA was performed Summary xxvii between the proposed methods and the reported method for each contaminant and no statistically significant difference was found. This thesis consists of 68 figures, 45 tables, 577 references |