Analytical study on some organophosphorus pesticides in their pure forms and in selected environmental samples / Omneya Kamel Elnaggar ; Supervised Abdelaziz Elbayoumi Abdelaleem , Mamdouh Reda Rezk , Shaban Mohamed Khalile

Thesis (Ph.D.) - Cairo University - Faculty of Pharmacy - Department of Analytical Chemistry

Simple, selective and accurate analytical methods were used for the determination of some organophosphorus pesticides in their pure forms and in commercial samples and for the determination of residues of diazinon and chlorpyrifos in lavender and rosemary leaves. The first method is TLC- densitometric method for the determination of diazinon, chlorpyrifos and temephos using petroleum ether: ethanol: glacial acetic acid (9.5: 0.5: 0.1, v/v/v) as mobile phase for diazinon. For chlorpyrifos and temephos, petroleum ether: ethanol: glacial acetic acid (9.0: 1.0: 0.1, v/v/v) was used as a mobile phase. Detection of bands was done at 230 nm for chlorpyrifos and 254 nm for diazinon and temephos using dibutyl phthalate as internal standard. This method also allowed extraction of diazinon and chlorpyrifos from lavender and rosemary leaves and separation of the pesticides from plant co-extractives depending on different Rf values. The second method was HPLC for determination of diazinon, chlorpyrifos and temephos in their pure forms, in their commercial samples and in the presence of their degradation products. Separation was carried out on Eclipse plus C18 column using a mobile phase consisting of acetonitrile: water (70: 30, v/v) with a flow rate of 1.5 ml min-1 and UV detection at 247, 230 and 254 nm for diazinon, chlorpyrifos and temephos, in order using dibutyl phthalate as an internal standard with diazinon and chlorpyrifos and fenitrothion as an internal standard with temephos

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