Date of Defense
10-4-2025 11:00 AM
Location
F3-022
Document Type
Thesis Defense
Degree Name
Master of Science in Chemistry
College
COS
Department
Chemistry
First Advisor
Prof. Mohammed Meetani
Keywords
Pesticides residues, Drug Thiabendazole Residue, Camil Milk, Dates, HPLC-FLD, LC– ESI (+)-MS/MS, MRL, Internal Standard, Standard Addition, QuEChERS, UAE
Abstract
In this thesis the detection and quantification of the traces of multi-residue pesticides in 26 dates samples as well as the presence of the anthelmintic drug thiabendazole in pasteurized commercial milk consumed in the United Arab Emirates is examined. The main objective of this thesis is two folds. First is to determine whether a selected group of 12 pesticides of 8 different groups- in the case of dates- and the drug thiabendazole-in case of camel milk- exists in the randomly collected samples of corresponding matrices. Second, is to quantify these compounds and compare their amount to the established maximum residue limits (MRL)set by the European Commission according to regulation (EU) 2020/585. Two different techniques were used for detection and the quantification, namely the standard addition method using HPLC-FLD instrument in case of thiabendazole in camel milk and the internal standard method using LC–ESI (+)-MS/MS in the case of the12 pesticides in dates. Thiabendazole extraction from camel milk samples was based on liquid-liquid extraction while quick, easy, cheap, effective, rugged, safe (QuEChERS) technique was used for dates sample preparation. Results shows that EPN, Azoxystrobin and Metalaxyl concentrations are higher than their corresponding MRLs (10 ppb in the case of the first two pesticides and 50 ppb for Metalaxyl) in some of the dates real samples while Carosulfan was consistently higher than its 10 ppb in more than half of the 25 collected real samples. Thiabendazole conversely is below the set MRL in all milk real samples. The LC–ESI (+)-MS/MS developed method could detect pesticides in the range of sub ppb (0.5 ppb) for 11 out of 12 pesticides while the HPLC-FLD detected Thiabendazole as low as 20 ppb. The results obtained by the developed LC–ESI (+)-MS/MS and HPLC-FLD methods can provide a strong basis for future instructions to be set by monitoring and regulatory bodies for ensuring quality control of food products such as camel milk and dates consumed in the UAE.
DETECTION AND QUANTITATION OF DRUGS AND PESTICIDES IN FOOD PRODUCTS OF THE UAE (DATES AND CAMEL MILK) BY LIQUID CHROMATOGRAPHIC TECHNIQUES
F3-022
In this thesis the detection and quantification of the traces of multi-residue pesticides in 26 dates samples as well as the presence of the anthelmintic drug thiabendazole in pasteurized commercial milk consumed in the United Arab Emirates is examined. The main objective of this thesis is two folds. First is to determine whether a selected group of 12 pesticides of 8 different groups- in the case of dates- and the drug thiabendazole-in case of camel milk- exists in the randomly collected samples of corresponding matrices. Second, is to quantify these compounds and compare their amount to the established maximum residue limits (MRL)set by the European Commission according to regulation (EU) 2020/585. Two different techniques were used for detection and the quantification, namely the standard addition method using HPLC-FLD instrument in case of thiabendazole in camel milk and the internal standard method using LC–ESI (+)-MS/MS in the case of the12 pesticides in dates. Thiabendazole extraction from camel milk samples was based on liquid-liquid extraction while quick, easy, cheap, effective, rugged, safe (QuEChERS) technique was used for dates sample preparation. Results shows that EPN, Azoxystrobin and Metalaxyl concentrations are higher than their corresponding MRLs (10 ppb in the case of the first two pesticides and 50 ppb for Metalaxyl) in some of the dates real samples while Carosulfan was consistently higher than its 10 ppb in more than half of the 25 collected real samples. Thiabendazole conversely is below the set MRL in all milk real samples. The LC–ESI (+)-MS/MS developed method could detect pesticides in the range of sub ppb (0.5 ppb) for 11 out of 12 pesticides while the HPLC-FLD detected Thiabendazole as low as 20 ppb. The results obtained by the developed LC–ESI (+)-MS/MS and HPLC-FLD methods can provide a strong basis for future instructions to be set by monitoring and regulatory bodies for ensuring quality control of food products such as camel milk and dates consumed in the UAE.
