نتایج جستجو برای: gc gas chromatography

تعداد نتایج: 355974  

2011
LACRIMIOARA SENILA ADRIANA GOG MARIN SENILA CECILIA ROMAN LUMINITA SILAGHI-DUMITRESCU

The aim of this study was the development and validation of a new method for carbohydrates analyses obtained from woody biomass, as a step of bioethanol production. In this study, we have quantified carbohydrates in wood by gas chromatography (GC) after derivatization. Quantification of carbohydrates was made by liquid-liquid extraction, oximation and silylation and, finally, analysis by gas ch...

Journal: :Bioresource technology 2005
Ana Gutiérrez José C del Río

The composition of pitch deposits occurring in pulp sheets and mill circuits during soda/anthraquinone pulping and elemental chlorine-free pulp bleaching of bast fibers of industrial hemp (Cannabis sativa) was studied. Pitch deposits were extracted with acetone, and the extracts analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Acetone extracts (15-25% of pit...

Journal: :Analytical chemistry 2009
Koffi Badjagbo Alexandra Furtos Mehran Alaee Serge Moore Sébastien Sauvé

Atmospheric pressure chemical ionization-tandem mass spectrometry (APCI-MS/MS) was applied for the first time to the direct analysis of octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in gaseous matrixes without extraction or prior chromatographic separation. Mass spectrometric characteristics of both compounds under APCI conditions and their fragmentation behavior in MS...

2005

Gas chromatography-mass spectroscopy (GC-MS) is one of the so-called hyphenated analytical techniques. As the name implies, it is actually two techniques that are combined to form a single method of analyzing mixtures of chemicals. Gas chromatography separates the components of a mixture and mass spectroscopy characterizes each of the components individually. By combining the two techniques, an...

Different solvent extracts of a red algae, Hypnea flagelliformis,and two brown algae, Cystoseira myrica and Sargassum boveanum, collected from the Persian Gulf coast were subjected to different bioassays including: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assay, antibacterial and antifungal activity by thin layer chromatography (TLC)-bioautography, agar disc diffusion (ADD) ...

Journal: :Journal of occupational health 2004
Sukesh Narayan Sinha H Venkatakrishna-Bhatt

Chromatography is an analytical technique employed for purification and separation of organic and inorganic substances including characterisation and quantitative measurement of compounds (table). Basically there are two types: l. Gas chromatography (GC), 2. Liquid chromatography (LC). Although discovered in 1906 by Tshett, developed in the 1950s as the GC technique where the mobile phase are g...

2008
Renata Raina Patricia Hall

A comparison of detection limits of gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) with gas chromatography-tandem mass spectrometry (GC-MS/MS) in selected reaction monitoring (SRM) mode with both electron ionization (EI) and negative-ion chemical ionization (NCI) are presented for over 50 pesticides ranging from organochlorines (OCs), organophosphorus pesticides (...

2007
G. Abraham

The triacylglyceride components of cottonseed oil were isolated and positively identified by a combination of high performance liquid chromatography (HPLC) and gas chromatography (GC). Both reversed-phase HPLC and capillary GC were capable of separating the oil into triacylglyceride peaks. These peaks were isolated by HPLC and their component acyl groups were converted to fatty acid methyl este...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه الزهراء - دانشکده علوم پایه 1386

چکیده ندارد.

2014
Kamran Javed Naquvi S. H. Ansari Mohd. Ali A. K. Najmi

The volatile oil obtained by hydrodistillation of the petals of Rosa damascena Mill. (Rosaceae) was analyzed by gas chromatography and gas chromatography/mass spectrometry (GC/MS). The yield of the oil was 0.12 % (v/w). Fifty compounds representing 99.06 % of the oil were characterized. The volatile oil was found rich in sesquiterpenes and aliphatic components, consisting of two monoterpenic es...

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