Sharif Digital Repository

A high-throughput micro-solid-phase extraction device based on a 96-well plate was constructed and applied to the determination of pesticide residues in various apple samples. Butyl methacrylate and ethylene glycol dimethacrylate were copolymerized as a monolithic polymer and placed in the cylindrically shaped stainless-steel meshes of 96-micro-solid-phase extraction device and used as an extracting unit. Before the micro-solid-phase extraction, microwave-assisted extraction was employed to facilitate the transfer of the pesticide residues from the apple matrix to liquid media. Then, 1 mL of the aquatic samples was transferred into the 96-well plate and the 96-micro-solid-phase extraction... 

A new unbreakable solid-phase microextraction fiber coating based on polyethylene terephthalate/graphene nanocomposite was developed. The nanocomposite coatings were prepared by an electrospinning technique using a polyethylene terephthalate (PET) polymer solution containing the dispersed graphene on the outer surface of a stainless-steel rod. The applicability of polyethylene terephthalate/graphene nanocomposite coatings was examined by extraction of organochlorine compounds (OCs) including heptachlor epoxide, aldrin, γ-HCH, and β-HCH from aqueous samples in headspace mode. Influential parameters on extraction efficiency such as polymer concentration, the weight ratio of components, the... 

A simple, rapid and sensitive method based on microextraction in packed syringe (MEPS), in combination with gas chromatography-mass spectrometry (GC-MS) was developed. Polyaniline (PANI) nanowires network was synthesized and used as sorbent of MEPS for the multiresidue determination of selected analytes from triazine, organochlrorine and organophosphorous pesticides in aqueous samples. The PANI nanowires network was prepared using soft template technique and its characterization was studied by scanning electron microscopy (SEM). The presence of micelles in this methodology showed to be an important parameter in shaping the growing polymer. Hexadecyltrimethylammonium bromide (HTAB) was used... 

A nanocomposite of silica-polydiphenylamine doped with silver nanoparticles (Ag-SiO2-PDPA) was successfully synthesized by the sol-gel process. For its preparation, PDPA was mixed with butanethiol capped Ag nanoparticles (NPs) and added to the silica sol solution. The Ag NPs were stabilized as a result of their adsorption on the SiO2 spheres. The surface characteristic of nanocomposite was investigated using scanning electron microscopy (SEM). In this work the Ag-SiO2-PDPA nanocomposite was employed as an efficient sorbent for micro-solid-phase extraction (μ-SPE) of some selected pesticides. An amount of 15 mg of the prepared sorbent was used to extract and... 

Reinforced polydiphenylamine (PDPA) nanocomposite was synthesized by oxidation of diphenylamine in 4molL-1 sulfuric acid solution containing a fixed amount of carbon nanotubes (CNTs) in the presence of cetyltrimethylammonium bromide (CTAB). The surface characteristic of PDPA and PDPA/CNT nanocomposites was investigated using scanning electron microscopy (SEM). The prepared PDPA/CNT nanocomposite was used as an extraction medium for microextraction in packed syringe (MEPS) of selected pesticides from aquatic environment. The effect of CNT doping level and the presence of surfactant on the extraction capability of nanocomposite was investigated and it was revealed that when 4% (w/w) of CNT in...