abderaz the composition of the essential oil obtained from the seeds of ammi majus l. which collected from province of khozestan in the southwest area of iran.the oils was analyzed by gas chromatography mass spectrometry (gc-ms). twenty - eight components have been identified in the extract of a. majus l. with toluene (3.766%), thymol (12.811%), carvacrol (37.811%) as major components, respecti...

the essential oil from the seeds of cuminum cyminum l. was isolated by hydrodistillation method and the chemical composition was determined by gas chromatography-mass spectrometry (gc/ms). the yield of the oil was found to be 3.0% (on dry weight basis). a total of twenty six components, representing 96.7% of the oil were identified. cuminaldehyde (49.4%), p-cymene (17.4%), b-pinene (6.3%), a-ter...

A coal tar pitch was fractionated by solvent solubility into heptane-solubles, heptane-insoluble/toluene-solubles (asphaltenes), and toluene-insolubles (preasphaltenes). The aim of the work was to compare the mass ranges of the different fractions by several different techniques. Thermogravimetric analysis, size-exclusion chromatography (SEC) and UV-fluorescence spectroscopy showed distinct dif...

A combined gas chromatography–mass spectrometry (GC–MS) with headspace solid-phase microextraction (HS-SPME) method has been employed for the analysis of the flavor volatiles of some Iranian rice cultivars (Domsiah, Deylamani, Hashemi, Shirodi and Tarom). The samples were grown in different cities of Mazandaran province. The sampling procedure and chromatographic conditions were same for all sa...

Compared to other analytical platforms, comprehensive two-dimensional gas chromatography coupled with mass spectrometry (GC×GC-MS) has much increased separation power for analysis of complex samples and thus is increasingly used in metabolomics for biomarker discovery. However, accurate peak detection remains a bottleneck for wide applications of GC×GC-MS. Therefore, the normal-exponential-Bern...

A gas chromatography mass spectrometry with spike calibration curve method was used to quantify three carbamate pesticides residue in cooked white rice and to estimate the reduction percentage of the cooking process duration. The selected pesticides are three carbamate pesticides including carbaryl and pirimicarb that their MRL is issued by “The Institute of Standards of Iran” and propoxur whic...

Abstract Two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOFMS) is a powerful tool for identification of compounds in complex samples. Herein, we compared the GC GC-TOFMS and systems polar metabolite profiling rice seeds. Forty-seven thirty-six metabolites were detected Korean cultivar, Dongjin, using GC-TOFMS, respectively. The limits detection shikimic,...

Two common analytical chemical problems often encountered when using chromatographic techniques in drug analysis are matrix interferences and ion suppression. Common sample preparation often involves the dilution of the sample prior to injection onto an instrument, especially for liquid chromatography-mass spectrometry (LC-MS) analyses. This practice frequently does not minimize or eliminate co...

The essential oils of wintergreen and birch are composed primarily methyl salicylate. Because this compound can easily be synthesized, frequently adulterated. By using Gas chromatography-combustion/pyrolysis-isotope ratio mass spectrometry (GC-C/P-IRMS) in conjunction with TC/EA-IRMS, GC-FID, GC-MS, 14C radiocarbon dating, criteria will established that used to distinguish authentic natural fro...

Persistent organic pollutants (POPs) are typically monitored via targeted mass spectrometry, which potentially identifies only a fraction of the contaminants actually present in environmental samples. With new anthropogenic compounds continuously introduced to the environment, novel and proactive approaches that provide a comprehensive alternative to targeted methods are needed in order to more...