Search for: bagheri--h
0.006 seconds
Total 40 records

    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 Es-Haghi, A ; 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... 

    Preparation, characterization, and applications of a novel solid-phase microextraction fiber by sol-gel technology on the surface of stainless steel wire for determination of poly cyclic aromatic hydrocarbons in aquatic environmental samples

    , Article Analytica Chimica Acta ; Vol. 813 , 2014 , pp. 48-55 ; ISSN: 00032670 Es-haghi, A ; Hosseininasab, V ; Bagheri, H ; Sharif University of Technology
    A novel solid-phase microextraction(SPME) fiber was prepared using sol-gel technology with ethoxylated nonylphenol as a fiber coating material. The fiber was employed to develop a headspace SPME-GC-MS method suitable for quantification of 13 polycyclic aromatic hydrocarbons (PAHs) in water samples. Surface characteristics of the fibers were inspected by energy dispersive X-ray (EDX) spectroscopy as well as by scanning electron microscopy (SEM). The SEM measurements showed the presence of highly porous nano-sized particles in the coating. Important parameters affecting the extraction efficiency such as extraction temperature and time, desorption conditions as well as ionic strength have been... 

    In situ solid-phase microextraction and post on-fiber derivatization combined with gas chromatography-mass spectrometry for determination of phenol in occupational air

    , Article Analytica Chimica Acta ; Volume 742 , 2012 , Pages 17-21 ; 00032670 (ISSN) Es haghi, A ; Baghernejad, M ; Bagheri, H ; Sharif University of Technology
    Elsevier  2012
    A method based on solid-phase microextraction (SPME) followed by on-fiber derivatization and gas chromatography-mass spectrometry detection (GC-MS) for determination of phenol in air was developed. Three different types of SPME fibers, polar and non-polar poly(dimethylsiloxane) (PDMS) and polyethylene glycol (PEG) were synthesized using sol-gel technology and their feasibility to the sampling of phenol were investigated. Different derivatization reagents for post on-fiber derivatization of phenol were studied. Important parameters influencing the extraction and derivatization process such as type of fiber coating, type and volume of derivatizing reagent, derivatization time and temperature,... 

    A superhydrophobic silica aerogel with high surface area for needle trap microextraction of chlorobenzenes

    , Article Microchimica Acta ; Volume 184, Issue 7 , 2017 , Pages 2151-2156 ; 00263672 (ISSN) Baktash, M. Y ; Bagheri, H ; Sharif University of Technology
    Springer-Verlag Wien  2017
    The authors have synthesized a superhydrophobic silica aerogel by using a sol-gel technique. The material is shown to be an efficient sorbent for needle trap microextraction of chlorobenzenes. Hydrophobicity affects the performance of the sorbent as shown by altering the ratio between tetraethylorthosilicate (TEOS) and methyltrimethoxysilane when synthesizing the sorbent. The observed contact angle (which is >150°) underpins the superhydrophobic properties of the aerogel. The microstructure of the sorbent was investigated by BET adsorption, revealing a surface area above 1000 m2 g−1. The sorbent was applied to needle trap extraction of chlorobenzenes from aqueous samples, and their... 

    Silica aerogel coated on metallic wire by phase separation of polystyrene for in–tube solid phase microextraction

    , Article Journal of Chromatography A ; Volume 1500 , 2017 , Pages 69-75 ; 00219673 (ISSN) Baktash, M. Y ; Bagheri, H ; Sharif University of Technology
    Elsevier B.V  2017
    In this research, an attempt was made toward synthesizing a sol–gel–based silica aerogel and its subsequent coating on a copper wire by phase separation of polystyrene. Adaption of this new approach enabled us to coat the metallic wire with powder materials. The use of this method for coating, led to the formation of a porous and thick structure of silica aerogel. The coated wire was placed in a needle and used as the sorbent for in–tube solid phase microextraction of chlorobenzenes (CBs). The superhydrophobicity of sorbent on extraction efficiency was investigated by using different ratios of tetraethylorthosilicate/methyltrimethoxysilane. The surface coated with the prepared silica aerogel... 

    A core–shell titanium dioxide polyaniline nanocomposite for the needle-trap extraction of volatile organic compounds in urine samples

    , Article Journal of Separation Science ; Volume 40, Issue 9 , 2017 , Pages 1985-1992 ; 16159306 (ISSN) Banihashemi, S ; Bagheri, H ; Sharif University of Technology
    Wiley-VCH Verlag  2017
    We synthesized a titanium dioxide–polyaniline core–shell nanocomposite and implemented it as an efficient sorbent for the needle-trap extraction of some volatile organic compounds from urine samples. Polyaniline was synthesized, in the form of the emeraldine base, dissolved in dimethyl acetamide followed by diluting with water at pH 2.8, using the interfacial polymerization method. The TiO2 nanoparticles were encapsulated inside the conducting polymer shell, by adapting the in situ dispersing approach. The surface characteristics of the nanocomposite were investigated by Fourier transform infrared spectrometry, scanning electron microscopy, and transmission electron microscopy. After... 

    Immobilization of functionalized gold nanoparticles in a well-organized silicon-based microextracting chip followed by online thermal desorption-gas chromatography

    , Article Microchemical Journal ; Volume 143 , 2018 , Pages 205-211 ; 0026265X (ISSN) Allahdadlalouni, M ; Bagheri, H ; Zamani, C ; Sharif University of Technology
    Elsevier Inc  2018
    In this survey, firstly, a silicon wafer-based microchip, possessing a 50-cm microchannel with the dimensions of 120 and 60 μm, was manufactured by chemical etching technique. Subsequently, the inner surface of the microchannel was coated with a primary layer of gold nanoparticles synthesized by galvanic displacement. Then a self-assembled monolayer of 3-mercaptopropyltriethoxysilane was immobilized on the first layer. Eventually, a polydimethylsiloxane film with a thickness of 16 ± 1 μm was formed on the walls of the microchannel by means of sol-gel method. Field emission scanning electron microscopy and atomic force microscopy were extensively employed to investigate the status of both... 

    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) Enteshari Najafabadi, M ; 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... 

    Porous eco–friendly fibers for on–line micro solid–phase extraction of nonsteroidal anti–inflammatory drugs from urine and plasma samples

    , Article Journal of Chromatography A ; Volume 1574 , 2018 , Pages 18-26 ; 00219673 (ISSN) Golzari Aqda, T ; Behkami, S ; Bagheri, H ; Sharif University of Technology
    Elsevier B.V  2018
    In this study, cellulose acetate (CA) fibers were prepared using different solvent systems in electrospinning. The recorded scanning electron microscopy micrographs indicated that the morphology of the prepared fibers is closely associated with the type of electrospinning solvents. The prepared CA fibers were used as an extractive phase for on–line micro–solid phase extraction (μ-SPE) of nonsteroidal–inflammatory drugs (NSAIDs) in biological samples pursued by HPLC–UV determination. Work conducted on this research ascertained that the use of dichloromethane:acetone (3:1, v/v) solvent system in the CA dissolution for electrospinning, leads to the formation of porous ribbon–like fibers and... 

    Wireless electrochemical preparation of gradient nanoclusters consisting of copper(II), stearic acid and montmorillonite on a copper wire for headspace in-tube microextraction of chlorobenzenes

    , Article Microchimica Acta ; Volume 185, Issue 1 , 2018 ; 00263672 (ISSN) Enteshari Najafabadi, M ; Bagheri, H ; Sharif University of Technology
    Springer-Verlag Wien  2018
    This work introduces a new gradient fiber coating for microextraction of chlorobenzenes. Nanoclusters of organoclay-Cu(II) on a copper wire were fabricated by wireless electrofunctionalization. The resultant gradient coatings are more robust, and thermally and mechanically stable. Wireless electrofunctionalization was carried out in a bipolar cell under a constant deposition potential and using an ethanolic electrolyte solution containing stearic acid and montmorillonite. Stearic acid acts as an inexpensive and green coating while montmorillonite acts as a modifier to impart thermal stability. The gradient morphology of the nanoclusters was investigated by scanning electron microscopy,... 

    A turn-on graphene quantum dot and graphene oxide based fluorometric aptasensor for the determination of telomerase activity

    , Article Microchimica Acta ; Volume 186, Issue 12 , 2019 ; 00263672 (ISSN) Kazemi, E ; Bagheri, H ; Norouzian, D ; Sharif University of Technology
    Springer-Verlag Wien  2019
    A turn-on fluorometric assay is described for determination of the activity of enzyme telomerase. For this purpose, graphene quantum dots (GQDs) were first modified with the telomeric sequence (5′-amino-AATCCGTCGAGCAGAGTT-3′) via a condensation reaction. Injection of graphene oxide causes instant quenching of the blue fluorescence of the GQDs. Addition of cell extract containing telomerase, triggers the extension of telomer via addition of specific sequence (TTAGGG)n to its 3′ end. Fluorescence, best measured at excitation/emission wavelengths of 390/446 nm, is subsequently restored due to folding of the extended telomeric sequence into G-quadruplex structure. The method was applied to the... 

    Amine modified magnetic polystyrene for extraction of drugs from urine samples

    , Article Journal of Chromatography A ; Volume 1602 , 2019 , Pages 107-116 ; 00219673 (ISSN) Zeinali, S ; Maleki, M ; Bagheri, H ; Sharif University of Technology
    Elsevier B.V  2019
    Polystyrene is one of the best candidates as the extracting medium due to its high stability in different media and acceptable extraction capability. However, the hydrophobic nature and low wettability of polystyrene limits its application to non–polar analytes. To resolve this limitation, in this project, amine groups were chemically attached to the surface of magnetic polystyrene. The resulting hydrophilic magnetic particles were expected to be capable of extracting both polar and non–polar analytes. Non–steroidal anti–inflammatory drugs (NSAIDs) were chosen for testing the applicability of modified magnetic polystyrene according to the importance of their analysis and also their wide... 

    Toward higher extraction and enrichment factors via a double-reservoirs microfluidic device as a micro-extractive platform

    , Article Journal of Separation Science ; Volume 42, Issue 18 , 2019 , Pages 2985-2992 ; 16159306 (ISSN) Rezvani, O ; Baraazandeh, M ; Bagheri, H ; Sharif University of Technology
    Wiley-VCH Verlag  2019
    In this study, firstly, a double-reservoir and switchable prototype of a micro-chip along with the respective holders were fabricated. A cyclic desorption process using microliter volume of organic solvent was adopted to prevent any outdoor contamination. As extractive phases, two identical sheets of electrospun polyamide/polypyrrole/titania nanofibers were synthesized using core–shell electro-spinning technique and utilized for determination of memantine in plasma samples. Field emission scanning electron microscopy images showed a high degree of porosity and homogeneity throughout the sheet structure. Also, energy dispersive X-ray analysis confirmed the presence of titania, while the... 

    Generic extraction medium: From highly polar to non-polar simultaneous determination

    , Article Analytica Chimica Acta ; Volume 1066 , 2019 , Pages 1-12 ; 00032670 (ISSN) Zeinali, S ; Khalilzadeh, M ; Bagheri, H ; Sharif University of Technology
    Elsevier B.V  2019
    Sample preparation for non-target analysis is challenging due to the difficulty in the extraction of polar and non-polar analytes simultaneously. Most commercial solid sorbents lack the proper comprehensiveness for extraction of analytes with different physiochemical properties. A possible key is the combination of hydrophobic polymer and hydrophilic surface functional groups in solid based extraction methods in order to generate the susceptibility for retaining both polar and non-polar analytes. To pursue this goal, in this study, four polar groups including [sbnd]NH 2 , [sbnd]NO 2 , [sbnd]COOH, and [sbnd]COCH 3 were chemically bound to Amberlite XAD-4 substrate in order to prepare a... 

    Amine/phenyl gradient derived base layer as a comprehensive extractive phase for headspace cooled in–tube microextraction of volatile organic compounds in saliva

    , Article Journal of Pharmaceutical and Biomedical Analysis ; Volume 191 , 2020 Enteshari Najafabadi, M ; Bagheri, H ; Rostami, A ; Sharif University of Technology
    Elsevier B.V  2020
    A gradient derived base layer extractive phase was synthesized and applied for the determination of volatile organic compounds (VOCs) in saliva samples using the headspace cooled in–tube microextraction (HS–CITME) method. The base layers from three different sols of phenyltriethoxysilane (PTES), octyltrimethoxysilane (OTMS) and methyltrimethoxysilane (MTMS) as nonpolar precursors were individually dip coated on the stainless steel wires (SSW). Then, the hydrolyzed polar precursor aminopropyltriethoxysilane (APTES) reacted with the silanol groups already formed on the surface of SSWs via controlled rate infusion (CRI) method. The presence of polar and non–polar functional groups on the... 

    Silane–based modified papers and their extractive phase roles in a microfluidic platform

    , Article Analytica Chimica Acta ; Volume 1128 , 2020 , Pages 31-41 Hashemi Hedeshi, M ; Rezvani, O ; Bagheri, H ; Sharif University of Technology
    Elsevier B.V  2020
    Herein, some (modified) paper–based substrates were prepared and utilized as extractive phases in a microfluidic device and their extraction performances examined for analytes with different polarities. Reagents including hexadecyltrimethoxysilane (HDTMS), phenyltrimethoxysilane (PTES), (3-aminopropyl) triethoxysilane (APTES) and 3–(2,3–epoxypropoxy) propyltrimethoxysilane (EPPTMOS) were implemented for the modification process. Due to the induction of different silane functional groups, it was anticipated to have various interactions for the tested analytes. Eventually, the prepared paper sheets were used as extractive phases for solid–phase extraction within a microfluidic system. The... 

    Roles of metal, ligand and post synthetic modification on metal organic frameworks to extend their hydrophobicity and applicability toward ultra–trace determination of priority organic pollutants

    , Article Analytica Chimica Acta ; Volume 1125 , 2020 , Pages 231-246 Javanmardi, H ; Abbasi, A ; Bagheri, H ; Sharif University of Technology
    Elsevier B.V  2020
    Implementation of metal organic frameworks (MOFs) in the separation science has attracted many researchers attention. In this study, the role of metal, ligand, the reaction condition and modification on the extraction efficiency of some MOFs was investigated. Among the prevalent reported MOFs, some members of the MIL and MOF–5 families were chosen, and eleven MOF–based sorbents were prepared by changing the metal and ligand type, reaction condition, and/or functionality through post synthetic modification (PSM). MIL–101 and MIL–101–NH2 based structures were initially synthesized based on the chromium and iron salts. Also, three zinc–based structures including MOF–5, [NH2(CH3)2]2... 

    The geometrical characteristics of nickel-based metal organic framework on its entrapment capability

    , Article Journal of Chromatography A ; Volume 1610 , 2020 Javanmardi, H ; Abbasi, A ; Bagheri, H ; Sharif University of Technology
    Elsevier B.V  2020
    Here, a three dimensional nickel–based metal organic framework (MOF) was synthesized via solvothermal and room temperature protocols. In order to study the effects of the synthesis conditions on the physical properties such as pore sizes and shapes of the prepared MOFs, their extraction capabilities were examined. Both MOFs were characterized by Fourier transform infrared spectroscopy, powder X-ray diffraction, scanning electron microscopy, Brunauer–Emmett–Teller and thermogravimetric analyses. Brilliant properties such as porous structure, high surface area and considerable thermal stability make them reasonable candidates to be employed as efficient extractive phases. The efficiency of the... 

    A stable nitrogen-rich zinc-based metal organic framework to investigate the structural similarity effect on the sorption efficiency of nitrogen-containing compounds

    , Article Microchemical Journal ; Volume 170 , 2021 ; 0026265X (ISSN) Javanmardi, H ; Naderi, M ; Bagheri, H ; Sharif University of Technology
    Elsevier Inc  2021
    A stable porous zinc-based metal organic framework (MOF) containing nitrogen-rich bis-tetrazolate ligand was synthesized to study the role of similar structures concerning both extractive phase and the desired solutes to achieve greater sorption efficiency. With implementing a dispersive micro-solid phase extraction (d-µ-SPE) methodology, the sorption capability and influencing structural parameters i.e., porosity, surface area and interactions types were investigated for the synthesized zinc-bis-tetrazolate (ZnBT) MOF and compared with some synthesized sorbents such as MIL-101, MIL-101-NH2, cadmium naphthalene dicarboxylic acid dimethyl formamide [Cd(NDC)(DMF)], polyaniline and LiChrolut®... 

    Preparation of amine–modified lignin and its applicability toward online micro–solid phase extraction of valsartan and losartan in urine samples

    , Article Journal of Chromatography A ; Volume 1643 , 2021 ; 00219673 (ISSN) Taherzadeh Ghahfarrokhi, M ; Zeinali, S ; Bagheri, H ; Sharif University of Technology
    Elsevier B.V  2021
    In the present work, with the focus on an environmentally–friendly approach, some gels were prepared by synthesizing amine–modified lignin, extracted from sugarcane bagasse, and further esterification and subsequent freeze–drying. These lignin–based gels were implemented as extractive phases in an online micro–solid phase extraction (μSPE) setup in conjunction with high performance liquid chromatography (HPLC) with UV detector. The developed method was used for analytical determination of valsartan and losartan in urine samples. To study the effect of the functionalization process, the efficiency of the unmodified lignin and the functionalized lignin were compared both in the absence and the...