Date of Defense
15-4-2026 1:00 PM
Location
Room 037, F3 Building
Document Type
Dissertation Defense
Degree Name
Doctor of Philosophy in Chemistry
College
College of Science
Department
Chemistry
First Advisor
Mohammed Almeetani
Keywords
Pesticide residues, carbamates, organophosphorus, triazoles, food safety, UHPLC-MS/MS, camel milk, date palm fruit, polyoxometalate, health risk assessment, oxidative degradation
Abstract
The increasing use of pesticides in agriculture necessitates the development of sensitive and reliable analytical methods for accurate detection, risk assessment, and remediation. This dissertation focuses on the development and validation of advanced UHPLC-MS/MS-based methodologies for the determination of multiclass pesticide residues and their metabolites in complex food matrices, along with the remediation of organophosphorus pesticides in aqueous systems. Efficient sample preparation techniques, including liquid–liquid extraction (LLE) and QuEChERS-based dispersive solid-phase extraction, were optimized to reduce matrix interferences and enhance analytical performance. The developed methods were validated according to international guidelines (SANTE/11312/2021) and demonstrated excellent performance. Recoveries ranged between 70–120%, confirming good accuracy. Limits of detection (LOD) and quantification (LOQ) indicated high sensitivity, enabling trace-level detection. Calibration curves constructed using multiple concentration levels (7–10 points), showed excellent linearity (R² ≥ 0.99), demonstrating method robustness and reliability. The validated methods were applied to real samples, including camel milk and dates, revealing the presence of multiclass pesticide residues. While most concentrations were within regulatory limits, some compounds showed elevated levels, emphasizing the need for continuous monitoring. Probabilistic health risk assessment indicated that individual pesticide exposure remained within acceptable limits; however, cumulative exposure to certain pesticide classes may pose potential risks. In addition to analytical determination, this study investigated the remediation of organophosphorus pesticides in water using polyoxometalate-based catalytic systems. The results demonstrated effective degradation, highlighting the potential of advanced materials for environmental remediation. Overall, this dissertation presents a comprehensive framework integrating method development, validation, application, and remediation strategies. The findings contribute to advancements in analytical chemistry by enhancing detection capabilities in complex matrices and supporting food safety and environmental protection.
Included in
UHPLC-MS/MS-Based Method Development and Validation for Multiclass Pesticide Residues in Food: Risk Assessment and Water Remediation
Room 037, F3 Building
The increasing use of pesticides in agriculture necessitates the development of sensitive and reliable analytical methods for accurate detection, risk assessment, and remediation. This dissertation focuses on the development and validation of advanced UHPLC-MS/MS-based methodologies for the determination of multiclass pesticide residues and their metabolites in complex food matrices, along with the remediation of organophosphorus pesticides in aqueous systems. Efficient sample preparation techniques, including liquid–liquid extraction (LLE) and QuEChERS-based dispersive solid-phase extraction, were optimized to reduce matrix interferences and enhance analytical performance. The developed methods were validated according to international guidelines (SANTE/11312/2021) and demonstrated excellent performance. Recoveries ranged between 70–120%, confirming good accuracy. Limits of detection (LOD) and quantification (LOQ) indicated high sensitivity, enabling trace-level detection. Calibration curves constructed using multiple concentration levels (7–10 points), showed excellent linearity (R² ≥ 0.99), demonstrating method robustness and reliability. The validated methods were applied to real samples, including camel milk and dates, revealing the presence of multiclass pesticide residues. While most concentrations were within regulatory limits, some compounds showed elevated levels, emphasizing the need for continuous monitoring. Probabilistic health risk assessment indicated that individual pesticide exposure remained within acceptable limits; however, cumulative exposure to certain pesticide classes may pose potential risks. In addition to analytical determination, this study investigated the remediation of organophosphorus pesticides in water using polyoxometalate-based catalytic systems. The results demonstrated effective degradation, highlighting the potential of advanced materials for environmental remediation. Overall, this dissertation presents a comprehensive framework integrating method development, validation, application, and remediation strategies. The findings contribute to advancements in analytical chemistry by enhancing detection capabilities in complex matrices and supporting food safety and environmental protection.