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    Fatty acids profiling of avocado seed and pulp using gas chromatography–mass spectrometry combined with multivariate chemometric techniques

    , Article Journal of the Iranian Chemical Society ; Volume 13, Issue 10 , 2016 , Pages 1905-1913 ; 1735207X (ISSN) Aliakbarzadeh, G ; Sereshti, H ; Parastar, H ; Sharif University of Technology
    Springer Verlag  2016
    In the present study, the profiling of 17 fatty acids (FAs) in avocado seed and pulp was investigated. The fatty acids were extracted with vortex-assisted extraction, methyl esterified and finally preconcentrated by dispersive liquid–liquid microextraction. The preconcentrated fatty acid methyl esters (FAMEs) were analyzed using gas chromatography–mass spectrometry (GC–MS) to obtain qualitative and quantitative information. The GC–MS data were analyzed using multivariate curve resolution-alternating least squares (MCR-ALS) method to overcome general chromatographic problems such as overlapped peaks, background interference and peak shifts. The calibration data were prepared using pure... 

    Development and Application of Multivariate Curve Resolution Techniques for the Analysis of Complex Chromatographic Data

    , Ph.D. Dissertation Sharif University of Technology Parastar Shahri, Hadi (Author) ; Jalali Heravi, Mahdi (Supervisor)
    In recent years, chromatographic techniques as one of the most important analytical techniques have been greatly developed from instrumentation and data volume point of views. On the other side, multivariate curve resolution (MCR) techniques as a branch of chemometrics have potential for the analysis of multivariate and huge data sets. In addition, MCR methods have been developed very fast in these years and their potential have been shown in the analysis of different types of chemical data. Thus, combination of sophisticated chromatographic techniques (e.g. gas chromatography-mass spectrometry (GC-MS) or comprehensive two-dimensional gas chromatography (GC×GC)) with MCR techniques can be... 

    RMet: An automated R based software for analyzing GC-MS and GC×GC-MS untargeted metabolomic data

    , Article Chemometrics and Intelligent Laboratory Systems ; Volume 194 , 2019 ; 01697439 (ISSN) Moayedpour, S ; Parastar, H ; Sharif University of Technology
    Elsevier B.V  2019
    Gas chromatography-mass spectrometry (GC-MS) and comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) are powerful techniques for measurement of all metabolites in complex metabolic samples. However, analyzing GC-MS and especially GC×GC-MS metabolomic data is a major challenge to the researchers in the field of metabolomics mainly due to the complexity and large data size. In this regard, an automated R based software entitled RMet has been developed to overcome the challenges in the metabolomic analysis workflow of GC-MS and GC×GC-MS data sets. Additionally, it is able to facilitate the complex process of extracting reliable and useful biological information from... 

    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 Allahdad Lalouni, Misagh (Author) ; Bagheri, Habib (Supervisor) ; Eshaghi, Ali (Supervisor)
    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 Hosseini Nasab, Valiallah (Author) ; Bagheri, Habib (Supervisor) ; Es-haghi, Ali (Co-Advisor)
    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... 

    Solid Phase Dynamic Extraction Based on Polypyrrole Fiber for Determination Trace Amount of Atrazine in Aqueous Samples with GC-MS

    , M.Sc. Thesis Sharif University of Technology Rouhi, Zahra (Author) ; Bagheri, Habib (Supervisor)
    This research is a bout a novel sample prepration procedure that used polypyrrole film into a stainless steel needle as a fiber coating for solid phase dynamic extraction(SPDE) with using a home-made SPDE devise and gas chromatography – mass spectroscopy for the extraction and detectionof Atrazine from the aqueous sample in direct mode of SPDE. Polypyrrole film was directly electrodeposited into the needle in a aqueous sodium dodecyl sulfonate solution with pecial set up in optimom condition of potential, time and concentration of polypyrrole. To enhance the sensitivity of the SPDE , variables affecting adsorption and desorption steps such as temperature,time,PH, flowrate and ionic strength... 

    Analysis of Phenol in Occupational Air Oxadiargyl in Plant and Soil Samples by Solid Phase Microextraction in Combination with Gas Chromatography-Mass Spectrometry

    , M.Sc. Thesis Sharif University of Technology Bagherbejad, Masoud (Author) ; Bagheri, Habib (Supervisor) ; Eshaghi, Ali (Supervisor)
    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 Javanmardi, Hassan (Author) ; Bagheri, Habib (Supervisor) ; Abbasi, Alireza (Co-Advisor)
    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... 

    Electrocoagulation for COD and diesel removal from oily wastewater

    , Article International Journal of Environmental Science and Technology ; Volume 13, Issue 1 , 2016 , Pages 231-242 ; 17351472 (ISSN) Safari, S ; Azadi Aghdam, M ; Kariminia, H. R ; Sharif University of Technology
    Center for Environmental and Energy Research and Studies 
    This study investigated the diesel and COD removal from oily wastewater by electrocoagulation. Experiments were conducted in a 2-l reactor using aluminum and iron electrodes. Effects of different parameters including pH (3–11), time (10–60 min), voltage (4.5–10.5 V), supporting electrolyte (NaCl concentration), electrode material and initial diesel concentration (3500–11,000 mg/L) were studied in order to evaluate the efficiency of electrocoagulation. Furthermore, the consumption of energy and the amount of sludge produced by this method were evaluated. The highest removal efficiency (COD removal of 99.1 ± 0.2 % and diesel removal of 98.8 ± 0.2 %) was observed under the following conditions:... 

    Novel Unbreakable Solid Phase Microextraction Fibers by Electrodepositon of Silica Sol-Gel

    , M.Sc. Thesis Sharif University of Technology Sistani, Habiballah (Author) ; Bagheri, Habib (Supervisor)
    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 Akbarinejad, Alireza (Author) ; Bagheri, Habib (Supervisor)
    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... 

    Modification of Electrospun Nanofibers Towards Sorbents with Higher Aspect Ratio

    , M.Sc. Thesis Sharif University of Technology Najarzadekan, Hamid (Author) ; Bagheri, Habib (Supervisor)
    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 Manouchehri, Mahshid (Author) ; Bagheri, Habib (Supervisor)
    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... 

    Polymeric Fibers and Sorbents for SPME and In-Needle Device together with GC-MS for Analysis of Environmental Pollutants in Aquatic Media

    , Ph.D. Dissertation Sharif University of Technology Babanezhad Arimi, Esmaeil (Author) ; Bagheri, Habib (Supervisor)
    Sample preparation gradually becomes a major part of analysis, capable of taking up to 80% of the total time of a complete separation-based analytical process, which typically includes five steps, that is sampling, sample preparation, separation, detection and data analysis. Environmental application is a main cause driving the development of many procedures of sample preparation due to the increased public awareness that environmental contaminants are a health risk. The increased demands in the analysis of foods and natural products have brought another pressure to develop the technologies of sample preparation. The appearance of more sensitive and reliable methodology to monitor... 

    Electrospun Nanofibers and Their Application for Microextraction of Environmental Samples

    , Ph.D. Dissertation Sharif University of Technology Aghakhani, Ali (Author) ; Bagheri, Habib (Supervisor)
    Novel electrospun nanofibers and their applications as the microextractionsorbents are the centre of this research. Polymeric nanofibers with diameter in the scale of nano-to-micro were prepared by the electrospinning method and employed for microextraction purposes. Two major microextraction methods included solid phase microextraction (SPME) and micro-Solid phase extraction (µ-SPE). In the first work, a novel SPME fiber was fabricated by electrospinning method. A thin stainless steel wire was coated by the network of polymeric nanofibers. The polymeric nanofiber coating on the wire was mechanically stable due to the fine and continuous nanofibers formation around the wire with a three... 

    Superhydrophobic Materials as Nanosorbents for Extraction Methodologies

    , Ph.D. Dissertation Sharif University of Technology Baktash, Mohammad Yahya (Author) ; Bagheri, Habib (Supervisor)
    In the first work, a superhydrophobic polystyrene hollow fiber (PS–HF) was synthesized by electrospinning and used in microextraction of trazine herbicides from aquatic media followed by gas chromatography mass spectrometric (GC–MS) determination. Effects of different parameters influencing the extraction efficiency including the solvent extraction and its amount, the desorbing solvent and its amount, extraction time and ionic strength were optimized. The characteristic properties of the hollow fiber were studied by scanning electron microscopy (SEM). The limits of detection and quantification of the method under optimized condition were 2 and 6 ng L-1, respectively. The relative standard... 

    A Nanocomposite Based on Polyurethane and Cu-TATAB Metal-Organic Framework as a Highly Efficient Sorbent for the Microextraction of Some Chlorinated Pesticides in the Environmental Samples

    , M.Sc. Thesis Sharif University of Technology Afsordeh Lakhtaki, Amir Hossein (Author) ; Bagheri, Habib (Supervisor)
    In this research, Cu-TATAB/Polyurethane (PU) nanocomposite fibers were prepared via electrospinning method in order to increase the overall extraction efficiency. The incorporation of Cu-TATAB, as a metal organic framework (MOF), in the synthesized nanocomposite contributed to the enhanced efficiency. The prepared sorbent was implemented for the thin film microextraction (TFME) of organochlorine species and their determination was subsequently performed by gas chromatography-mass spectrometry (GC-MS). To achieve the maximum efficiency of the synthesized sorbent, the parameters of MOF percentage in nanocomposites, solvent type and volume, desorption time, solution ionic strength and... 

    Thorough analysis of Iranian spearmint essential oil: Combination of chemometrics and gas chromatography-mass spectrometry

    , Article Analytical Methods ; Vol. 6, Issue. 17 , 2014 , Pages 6753-6759 ; ISSN: 17599660 Jalali Heravi, M ; Moazeni-Pourasil, R. S ; Sereshti, H ; Sharif University of Technology
    The components of Iranian spearmint essential oil were identified and quantified using gas chromatography-mass spectrometry (GC-MS) combined with chemometric tools. A multivariate curve resolution (MCR) approach was used to overcome the problems of background, baseline offset and overlapping/embedded peaks in GC-MS. The peaks were resolved using heuristic evolving latent projection (HELP) and multivariate curve resolution-alternating least squares (MCR-ALS) techniques. A new pure variable selection method named multivariate curve resolution-objective function equal to zero (MCR-FEQZ) is introduced and was applied in this work. The performance of this technique was evaluated and confirmed... 

    Biodegradation of polychlorinated biphenyls by lysinibacillus macrolides and bacillus firmus isolated from contaminated soil

    , Article International Journal of Engineering, Transactions B: Applications ; Volume 32, Issue 5 , 2019 , Pages 628-633 ; 1728144X (ISSN) Samadi, A ; Sharifi, H ; Ghobadi Nejad, Z ; Yaghmaei, S ; Sharif University of Technology
    Materials and Energy Research Center  2019
    Polychlorinated biphenyls (PCBs) cause many significant ecological problems because of their low degradability, high harmfulness, and solid bioaccumulation.Two bacterial strains were isolated from soil that had been polluted with electrical transformer liquid for more than 40 years. The isolates were distinguished as Lysinibacillus macrolides DSM54Tand Bacillus firmus NBRC15306Tthrough 16S rRNA sequencing analysis.This is the primary report of an agent of the genus Bacillus firmus equipped for the removal of PCBs. The strains could develop broadly on 2-Chlorobiphenyl and 2,4-dichlorobiphenyl. GC/MS analysis of individual congeners revealed up to 80% degradation of the xenobiotics in 96h,... 

    Elimination of chromatographic and mass spectrometric problems in GC-MS analysis of Lavender essential oil by multivariate curve resolution techniques: Improving the peak purity assessment by variable size moving window-evolving factor analysis

    , Article Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences ; Volume 983-984 , 2015 , Pages 83-89 ; 15700232 (ISSN) Jalali Heravi, M ; Moazeni Pourasil, R. S ; Sereshti, H ; Sharif University of Technology
    In analysis of complex natural matrices by gas chromatography-mass spectrometry (GC-MS), many disturbing factors such as baseline drift, spectral background, homoscedastic and heteroscedastic noise, peak shape deformation (non-Gaussian peaks), low S/N ratio and co-elution (overlapped and/or embedded peaks) lead the researchers to handle them to serve time, money and experimental efforts. This study aimed to improve the GC-MS analysis of complex natural matrices utilizing multivariate curve resolution (MCR) methods. In addition, to assess the peak purity of the two-dimensional data, a method called variable size moving window-evolving factor analysis (VSMW-EFA) is introduced and examined. The...