Search for: acetic-acid
0.009 seconds
Total 47 records

    Modified solvent microextraction with back extraction combined with liquid chromatography-fluorescence detection for the determination of citalopram in human plasma

    , Article Analytica Chimica Acta ; Volume 610, Issue 2 , 2008 , Pages 211-216 ; 00032670 (ISSN) Bagheri, H ; Khalilian, F ; Babanezhad, E ; Es haghi, A ; Rouini, M. R ; Sharif University of Technology
    A modified solvent microextraction with back extraction method (SME/BE) combined with high performance liquid chromatography and fluorescence detection (HPLC-FD) was developed for the determination of citalopram in human plasma. Extraction process was performed in a home-made total glass vial without using a teflon ring, usually employed in SME/BE. Citalopram was first extracted from 0.5 mL of plasma, modified with sodium hydroxide, into hexane. Back extraction step was then performed into 5.2 μL of 45 mM ammonium formate solution (pH 4) using a GC microsyringe. The extract was subsequently transferred into a liner-like vial and then injected into the HPLC system. An enrichment factor of 150... 

    QSAR study of heparanase inhibitors activity using artificial neural networks and Levenberg-Marquardt algorithm

    , Article European Journal of Medicinal Chemistry ; Volume 43, Issue 3 , 2008 , Pages 548-556 ; 02235234 (ISSN) Jalali Heravi, M ; Asadollahi Baboli, M ; Shahbazikhah, P ; Sharif University of Technology
    A linear and non-linear quantitative structure-activity relationship (QSAR) study is presented for modeling and predicting heparanase inhibitors' activity. A data set that consisted of 92 derivatives of 2,3-dihydro-1,3-dioxo-1H-isoindole-5-carboxylic acid, furanyl-1,3-thiazol-2-yl and benzoxazol-5-yl acetic acids is used in this study. Among a large number of descriptors, four parameters classified as physico-chemical, topological and electronic indices are chosen using stepwise multiple regression technique. The artificial neural networks (ANNs) model shows superiority over the multiple linear regressions (MLR) by accounting 87.9% of the variances of antiviral potency of the heparanase... 

    Kinetic study of catalytic hydrolysis reaction of methyl acetate to acetic acid and methanol

    , Article Iranian Journal of Science and Technology, Transaction B: Engineering ; Volume 30, Issue 5 , 2006 , Pages 595-606 ; 03601307 (ISSN) Ehteshami, M ; Rahimi, N ; Eftekhari, A. A ; Nasr, M. J ; Sharif University of Technology
    The reaction kinetics and chemical equilibrium of the reversible catalytic hydrolysis reaction of a methyl acetate to acetic acid and methanol using a strongly acidic ion exchange resin catalyst named Amberlyst 15 were studied. To investigate the different behavior of Amberlyst 15 in the adsorption of reactants and product species, the equilibrium behavior of binary non-reactive liquid mixtures, consisting of one reactant and one product were studied experimentally. The Langmuir model was used to describe the equilibrium condition, quantitatively. Then the employed model was compared with the more complicated thermodynamic models to describe the equilibrium between the catalytic polymer... 

    Multicomponent nanoparticles as means to improve anaerobic digestion performance

    , Article Chemosphere ; Volume 283 , 2021 ; 00456535 (ISSN) Baniamerian, H ; Ghofrani Isfahani, P ; Tsapekos, P ; Alvarado Morales, M ; Shahrokhi, M ; Angelidaki, I ; Sharif University of Technology
    Elsevier Ltd  2021
    Sufficient quantity of trace metals is essential for a well performing anaerobic digestion (AD) process. Among the essential trace elements in active sites of multiple important enzymes for AD are iron and nickel ions. In the present study, iron and nickel in the form of Fe2O3 and NiO were coated on TiO2 nanoparticles to be used in batch and continuous operation mode. The effect of TiO2, Fe2O3–TiO2, and NiO–TiO2 nanoparticles on each step of AD process was assessed utilizing simple substrates (i.e. cellulose, glucose, acetic acid, and mixture of H2–CO2) as well as complex ones (i.e. municipal biopulp). The hydrolysis rate of cellulose substrate increased with higher dosages of the coated... 

    Dna-Rna hybrid (R-loop): From a unified picture of the mammalian telomere to the genome-wide profile

    , Article Cells ; Volume 10, Issue 6 , 2021 ; 20734409 (ISSN) Rassoulzadegan, M ; Sharifi Zarchi, A ; Kianmehr, L ; Sharif University of Technology
    MDPI  2021
    Local three-stranded DNA/RNA hybrid regions of genomes (R-loops) have been detected either by binding of a monoclonal antibody (DRIP assay) or by enzymatic recognition by RNaseH. Such a structure has been postulated for mouse and human telomeres, clearly suggested by the identification of the complementary RNA Telomeric repeat-containing RNA “TERRA”. However, the tremendous disparity in the information obtained with antibody-based technology drove us to investigate a new strategy. Based on the observation that DNA/RNA hybrids in a triplex complex genome co-purify with the double-stranded chromosomal DNA fraction, we developed a direct preparative approach from total protein-free cellular... 

    Immersed solvent microextraction and gas chromatography-mass spectrometric detection of s-triazine herbicides in aquatic media

    , Article Analytica Chimica Acta ; Volume 537, Issue 1-2 , 2005 , Pages 81-87 ; 00032670 (ISSN) Bagheri, H ; Khalilian, F ; Sharif University of Technology
    Elsevier  2005
    An immersed solvent microextraction (SME) method was successfully developed for the trace enrichment of s-triazine herbicides from aquatic media. A microdrop of butyl acetate was applied as the extraction solvent. After extraction, the microdrop was introduced directly into a gas chromatography-mass spectrometry (GC-MS) injection port. Some important extraction parameters such as type of solvent, extraction time, stirring rate, and temperature were investigated and optimized. The highest possible microdrop volume of 3 μl, a sampling temperature of 60°C, and use of butyl acetate are major parameters to obtain high enrichment factors. The enrichment factor and linearity was studied by... 

    A cheap, simple, and versatile method for acetylation of alcohols and phenols and selective deprotection of aromatic acetates under solvent-free condition

    , Article Synthetic Communications ; Volume 35, Issue 3 , 2005 , Pages 483-491 ; 00397911 (ISSN) Rajabi, F ; Saidi, M. R ; Sharif University of Technology
    Acyclic and cyclic acetates of various alcohols and phenols were obtained in excellent yields under mild reaction conditions in the presence of a catalytic amount of sodium hydroxide under solvent-free conditions and microwave irradiation. Selective deprotection of acetate group from the corresponding phenolic compounds was carried out in the presence of LiClO4· 2H2O. Copyright © Taylor & Francis, Inc