Search for: solid-phase-microextraction
Total 77 records
Chemically bonded carbon nanotubes on modified gold substrate as novel unbreakable solid phase microextraction fiber, Article Microchimica Acta ; Volume 174, Issue 3 , September , 2011 , Pages 295-301 ; 00263672 (ISSN) ; Ayazi, Z ; Sistani, H ; Sharif University of Technology
A new technique is introduced for preparation of an unbreakable fiber using gold wire as a substrate for solid phase microextraction (SPME). A gold wire is used as a solid support, onto which a first film is deposited that consists of a two-dimensional polymer obtained by hydrolysis of a self-assembled monolayer of 3-(trimethoxysilyl)-1-propanthiol. This first film is covered with a layer of 3-(triethoxysilyl)-propylamine. Next, a stationary phase of oxidized multi-walled carbon nanotubes was chemically bound to the surface. The synthetic strategy was verified by Fourier transform infrared spectroscopy and scanning electron microscopy. Thermal stability of new fiber was examined by...
A sol-gel-based amino functionalized fiber for immersed solid-phase microextraction of organophosphorus pesticides from environmental samples, Article Microchemical Journal ; Volume 94, Issue 1 , 2010 , Pages 1-6 ; 0026265X (ISSN) ; Ayazi, Z ; Babanezhad, E ; Sharif University of Technology
A method based on immersed solid-phase microextraction (SPME) and gas chromatography mass spectrometry detection (GC-MS) for the determination of organophosphorous pesticides (OPPs) in aqueous samples was developed. A sol-gel based coating fiber was prepared using 3-(trimethoxysilylpropyl) amine as precursor. The synthesized fiber was prepared in a way to impart polar moiety into the coating network and would be more suitable for extracting polar and semi-polar organic pollutants. Important parameters influencing the extraction process were optimized and an extraction time of 40 min at 30 °C gave maximum peak area, when NaCl (20% w/v) was added to the aqueous sample. The linearity for...
Coupling of a modified in-tube solid phase microextraction technique with high performance liquid chromatography-fluorescence detection for the ultra-trace determination of polycyclic aromatic hydrocarbons in water samples, Article Chromatographia ; Volume 59, Issue 7-8 , 2004 , Pages 501-505 ; 00095893 (ISSN) ; Salemi, A ; Sharif University of Technology
Friedr. Vieweg und Sohn Verlags GmbH 2004
A modified in-tube solid phase microextraction (SPME) technique in conjunction with a high performance liquid chromatography (HPLC) was developed for the trace determination of polycyclic aromatic hydrocarbons (PAHs) in water samples. The extraction device contained a regular HPLC syringe, replacing the metallic needle by two concentric fused silica capillary tubes. The capillary tubes were coated with polydimethylsiloxane (PDMS) as the sorbent and were attached to the syringe by a homemade interface made from polyether ether ketone (PEEK). The sorption of analytes was achieved by frequent withdrawing and ejecting the water sample from/into a vial via the capillary tubes. For the desorption...
Novel unbreakable solid-phase microextraction fibers on stainless steel wire and application for the determination of oxadiargyl in environmental and agricultural samples in combination with gas chromatography-mass spectrometry, Article Talanta ; Vol. 128, issue , 2014 , Pages 231-236 ; ISSN: 00399140 ; Baghernejad, M ; Bagheri, H ; Sharif University of Technology
Sol-gel based solid-phase microextraction fibers supported by a stainless steel wire were fabricated and employed for GC-MS determination of oxadiargyl in real samples. The fibers were based on four compounds with different polarity: polar and non-polar (end-capped) poly(dimethylsiloxane) (PDMS), polyethylene glycol (PEG), and poly(ethylene-propyleneglycol)-monobutyl ether (UCON). For this purpose, the surface of the stainless steel was initially modified by (3-mercaptopropyl) trimethoxysilane. The results of the modification procedure were evaluated by cyclic voltammetry and energy dispersive X-ray (EDX) spectroscopy. After the modification, four different sol-gel based SPME fibers with...
A Polypropylene-Based Microextraction Method Coupled with HPLC-FD for Determination of Fluoxetine in Human, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib
Considering principles of both micro-solid phase extraction (µ-SPE) and stir-bar sorptive extraction (SBSE) techniques, in this study a microextraction technique was developed using a polypropylene sheet as extracting device for isolation of fluoxetine from biological samples. Being rather inexpensive and simple to prepare extracting device, elimination of time consuming sorbent synthesis step and memory effect are some of the advantages of the proposed method. The extraction process was performed using a polypropylene sheet as extracting device. Solvent desorption was performed in a microvial and then extractant was injected into HPLC system. The effect of various parameters including pH,...
A highly thermal-resistant electrospun-based polyetherimide nanofibers coating for solid-phase microextraction Microextraction Techniques, Article Analytical and Bioanalytical Chemistry ; Vol. 406, issue. 8 , March , 2014 , p. 2141-2149 ; Akbarinejad, A ; Aghakhani, A ; Sharif University of Technology
A high-temperature-resisant solid-phase microextraction (SPME) fiber was prepared based on polyetherimide (PEI) by the electrospinning method. The PEI polymeric solution was converted to nanofibers using high voltages and directly coated on a stainless steel SPME needle. The scanning electron microscopy images of PEI coating showed fibers with diameter range of 500-650 nm with a homogeneous and smooth surface morphology. The SPME nanofibers coating was optimized for PEI percentage, electrospinning voltage, and time. The extraction efficiency of the coating was investigated for headspace SPME of some environmentally important polycyclic aromatic hydrocarbons from aqueous samples followed by...
Article Analytica Chimica Acta ; Volume 767, Issue 1 , March , 2013 , Pages 1-13 ; 00032670 (ISSN) ; Ayazi, Z ; Naderi, M ; Sharif University of Technology
Conductive polymers (CPs) are classified as materials which exhibit highly reversible redox behavior and the unusual combined properties of metal and plastics. CPs, due to their multifunctionality, ease of synthesis and their stability, have attracted more attentions in different fields of research, including sample preparation. CPs along with several commercial hydrophilic sorbents, are alternative to the commercially available hydrophobic sorbents which despite their high specific surface areas, have poor interactions and retentions in the extraction of polar compounds. This review covers a general overview regarding the recent progress and new applications of CPs toward their synthesis...
Article Analytical Chemistry ; Volume 79, Issue 3 , 2007 , Pages 1221-1230 ; 00032700 (ISSN) ; Zhang, X ; Ouyang, G ; Es-haghi, A ; Pawliszyn, J ; Sharif University of Technology
The on-fiber standardization technique for solid-coated solid-phase microextraction (SPME) was studied, and a theoretical model is proposed for the isotropic behavior of adsorption and desorption, based on Fick's law of diffusion and the Langmuir model. The isotropy of the adsorption and desorption of analytes onto and from the surface of porous solid SPME fiber was validated with the use of a commercially available fiber, a 50-μm Carbowax/ templated resin for carbamate pesticide analysis in various sample matrixes, and a self-made polypyrrole fiber for diazepam analysis in blood samples. Time constants were comparable for the adsorption and desorption processes. Equilibrium constants and...
Environmental Monitoring of Formaldehyde in Biologics Production Areas Using Solid-Phase Microextraction Coupled to Gas Chromatography Mass Spectrometry, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib ; Eshaghi, Ali
During the recent years, manufactures and industries have paid attention to occupational health and safety of their employees. Formaldehyde is known as a probable carcinogenic agent and its large consumption made industries to consider it as a risk factor for occupational health. At vaccine production industries, Formaldehyde is used as disinfectant and stabilizer. In this study, a solid-phase microextraction (SPME) method based on kinetic and equilibrium calibration strategies was developed for monitoring of formaldehyde in the biologics production areas. The application and feasibility of three different sol-gel based SPME fibers with different polarities have been investigated. Two...
A Sol-Gel-bonded Coating Deposited on the Surface of Stainless Steel Wire for Solid Phase Microextraction of Environmental Pollutants, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib ; Es-haghi, Ali
A novel SPME fiber was prepared using sol-gel technology with ethoxylated nonylphenol as a precursor and used for development of a headspace solid phase microextraction coupled with gas chromatography-mass spectrometry method for quantification of 13 priority polycyclic aromatic hydrocarbons in water samples. The fused silica is the material that has recently been used as a substrate in sol-gel works for preparation of SPME fibers. Given that its drawbacks such as breakability and fragility which make the work tedious and time consuming¬, in this survey stainless steel wires were chosen as a substrate for coating the sol-gel film on them. The fibers made from steel are vary sturdy and aren’t...
M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib
Conventional solid phase microextraction fibers posses relatively low recommended operating temperature, instability and swelling in organic solvents, breakage of the fiber, stripping of coatings, and bending of the needle. Some of these problems have been obviated by covalent bonding of the polymer phase to the fused-silica substrate by sol-gel technology, but the easy breakage of the fiber still is a remaining challenge In this work, after successful fabrication of unbreakable SPME fibers based on 3-(trimethoxysilyl)propyl methacrylate precursor deposited on the surface of copper wire, the same approach was carried out to synthesis new sol-gel based SPME fibers. Three different coated...
Analysis of Phenol in Occupational Air Oxadiargyl in Plant and Soil Samples by Solid Phase Microextraction in Combination with Gas Chromatography-Mass Spectrometry
Sharif University of Technology
In this study different kinds of solid phase microextraction fibers based on sol-gel technology were employed for extraction and pre-concentration of phenol in occupational air and oxadiargyl in plant and environmental samples. In the first work, a SPME method followed by on-fiber derivatization and gas chromatography-mass spectrometry detection (GC-MS) was developed for the analysis of phenol in the air. The application and feasibility of three different sol-gel based SPME fibers with different polarities, polar and non-polar poly (dimethylsiloxane) (PDMS) and polyethylene glycol (PEG), have been studied. Influential parameters such as fiber coating type, type of derivatization reagent,...
Three Dimensional Conductive Polymers within Metal-Rganicframeworks Asa new Extracting Medium with High Aspect Ratio Formicroextraction of Organiccompounds from Aquatic, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib ; Abbasi, Alireza
In this study, the SPME nanocomposite coating of metal organic framework/polyaniline (MOF/PANI) was fabricated by the electrochemical polymerization process. Its application was investigated via extraction of chlrobenzenes from head-space aqueous solution. The power supply voltage, time of deposition and the percent of added MOF to main polymer solution was investigated and optimized in the electrochemical polymerization process. Also extraction parameters influencing the extraction efficiency including ionic strength, extraction temperature, extraction time, as well as desorption temperature and time were investigated and optimized. The detection limits of the developed method under...
Gradient extractive phase prepared by controlled rate infusion method: An applicable approach in solid phase microextraction for non–targeted analysis, Article Journal of Chromatography A ; Volume 1574 , 2018 , Pages 130-135 ; 00219673 (ISSN) ; Kazemi, E ; Bagheri, H ; Sharif University of Technology
Elsevier B.V 2018
The aim of this study is to introduce an extractive phase based on gradient concept by continuous changing in chemical functional groups for non–targeted analysis. For this purpose, three different two–component coatings containing (3–aminopropyl)trimethoxysilane (APTES) as polar and either phenyltriethoxysilane (PTES), octyl–trimethoxysilane (OTMS) or methyltrimethoxysilane (MTMS) as nonpolar precursors were formed on the modified stainless steel wires using controlled rate infusion (CRI) method. The presence of polar and/or non–polar functional groups on the surface of substrate was evaluated by Fourier–transform infrared spectroscopy (FTIR) together with contact angles determined...
Electrospun polyethylene terephthalate/graphene nanocomposite as a new solid-phase microextraction fiber coating for enhanced determination of organochlorine compounds, Article Chromatographia ; Volume 81, Issue 10 , 2018 , Pages 1413-1420 ; 00095893 (ISSN) ; Roostaie, A ; Ehteshami, S ; Sharif University of Technology
Friedr. Vieweg und Sohn Verlags GmbH 2018
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...
Optimization of solid-phase microextraction of volatile phenols in water by a polyaniline-coated Pt-fiber using experimental design, Article Analytica Chimica Acta ; Volume 581, Issue 1 , 2007 , Pages 71-77 ; 00032670 (ISSN) ; Noroozian, E ; Jalali Heravi, M ; Mollahosseini, A ; Sharif University of Technology
Solid-phase microextraction (SPME) coupled to gas chromatography (GC) was applied to the extraction of phenol and some of its volatile derivatives in water samples. The SPME fiber consisted of a thin layer of polyaniline, which was electrochemically coated on a fine Pt wire. The stability of the coating was such that it could be used at temperatures as high as 325 °C, without any deterioration. The effects of various parameters affecting the extraction efficiency were studied, simultaneously. From these, optimization of the extraction temperature, extraction time, coating thickness, sample pH, salt concentration and desorption time was carried out by means of a (26-2) fractional factorial...
M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib
Commercial solid phase microextraction fibers posses a few drawbacks such as relatively low recommended operating temperature, instability and swelling in organic solvents, breakage of the fiber, stripping of coatings, and bending of the needle. Some of these problems have been obviated by covalent bonding of the polymer phase to the fused-silica substrate by sol-gel technology, but the easy breakage of the fiber remains a problem. In this study a new technique for preparation of unbreakable, thin and very porous fiber coatings for solid phase microextraction was proposed. In this technique firstly an intermediate film consisting ...
Development of a Solid-Phase Microextraction Method Based on Electrospun Polyetherimide Nanofibers for Determination of Polycyclic Aromatic Hydrocarbons in Aqueous Samples, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib
Attentions to nano materials due to their vast applications in different branches of science and technology have been remarkably increased in recent years. Nanofibers are an important class of nano materials which could be used as novel sorbents because of their high surface to volume ratio as a result of long lengths and nano-to-micro-scale diameters. Electrospinning is a broadly used technology which utilizes high electrostatic forces for producing nanofibers. In this study a novel high temperature resistant solid phase microextraction (SPME) fiber was prepared besed on Polyetherimide (PEI) by this method. The porosity of the PEI fiber was investigated by scanning electron microscopy...
M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib
In this study, a novel electrospun modified polyamide (PA) based nanofibers were synthesized and employed as fibers coating for rapid determination of chlorophenols. The major polymer solution contained PA along with polyethylene glycol (PEG), acting as a side low molecular weight polymer. After production of the PA−PEG fiber coating, PEG was subsequently removed and modified by water which was confirmed by Fourier transform infra-red spectrometry.The scanning electron microscopy images showed anaverage diameter of 640 and 148 nmforPA and PA−PEG coatings, respectively while the latter coating structure was homogeneous and porous.The extraction efficiency of unmodified and modified coatings...
Nanomagnetic Polyamidoamine Dendrimer as A Novel Sorbent for Solid Phase Microextraction of Chlorophenols from Aquatic Media, M.Sc. Thesis Sharif University of Technology ; Bagheri, Habib
In this study, ananomagnetic polyamidoamine (PAMAM) dendrimer was synthesized as a novel SPME fiber coating and implemented to the determination of traces of chlorophenols in water samples. The synthesized magnetic PAMAM shows to have many polar groups with an enhanced internal porosity which is promising to be used as an efficient extracting medium. With this purpose, a thin stainless steel wire was coated by the network of dendritic PAMAM polymer through electrolysis and chemical reactions. The synthesized fiber is physical stable since it was chemically bonded to the substrate. Extraction efficiency of new coating was investigated by headspace SPME of chlorophenols from aqueous samples...