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limonene
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Chemical composition and antibacterial activity of dracocephalum kotschyi essential oil obtained by microwave extraction and hydrodistillation
, Article International Journal of Food Properties ; Volume 20 , 2017 , Pages S306-S315 ; 10942912 (ISSN) ; Mirzania, F ; Sonboli, A ; Matloubi Moghaddam, F ; Sharif University of Technology
Abstract
Dracocephalum kotschyi essential oils obtained by hydrodistillation (HD), microwave-assisted hydrodistillation (MAHD), and solvent-free microwave extraction (SFME) were investigated by GC-FID (Gas Chromatography-Flame Ionization Detector) and GC-MS (Gas Chromatography-Mass Spectrometry). The percentage of oxygenated compounds was significantly increased from 62.52% in HD to 76.47% in MAHD, and 84.52% in SFME. Conversely, the monoterpene hydrocarbons were decreased from 30.84% in HD to 13.71% in MAHD, and 5.85% in SFME. The main compound in the essential oil obtained by HD is limonene, which accounted for more than 30% of the oil, while the percentage of this compound was reduced to 9.52% in...
Immobilization of a molybdenum complex on the surface of magnetic nanoparticles for the catalytic epoxidation of olefins
, Article New Journal of Chemistry ; Volume 40, Issue 2 , 2016 , Pages 1580-1586 ; 11440546 (ISSN) ; Moradi Shoeili, Z ; Bagher Zadeh, M ; Akbayrak, S ; Özkar, S ; Sharif University of Technology
Royal Society of Chemistry
Abstract
Novel organic-inorganic hybrid heterogeneous nanocatalysts were obtained by covalent anchoring of a molybdenum(vi) complex of salicylidene 2-picoloyl hydrazine, MoO2(sal-phz)(CH3OH), (1) on the surface of magnetic nanoparticles functionalized by one of two routes: in the first method, the surface of magnetic nanoparticles is directly modified with 3-chloropropyltrimethoxysilane yielding 1A. In the second method, magnetic nanoparticles were silica-coated with tetraethoxysilane and then with 3-chloropropyltrimethoxysilane yielding the intermediate 2B. Then complex 1 was grafted on the surface of 1A or 2B through covalent interaction yielding 2A or 3B, respectively. The nanocatalysts 2A and 3B...
Fuzzy C-means clustering for chromatographic fingerprints analysis: A gas chromatography-mass spectrometry case study
, Article Journal of Chromatography A ; Volume 1438 , 2016 , Pages 236-243 ; 00219673 (ISSN) ; Bazrafshan, A ; Sharif University of Technology
Elsevier
Abstract
Fuzzy C-means clustering (FCM) is proposed as a promising method for the clustering of chromatographic fingerprints of complex samples, such as essential oils. As an example, secondary metabolites of 14 citrus leaves samples are extracted and analyzed by gas chromatography-mass spectrometry (GC-MS). The obtained chromatographic fingerprints are divided to desired number of chromatographic regions. Owing to the fact that chromatographic problems, such as elution time shift and peak overlap can significantly affect the clustering results, therefore, each chromatographic region is analyzed using multivariate curve resolution-alternating least squares (MCR-ALS) to address these problems. Then,...