نتایج جستجو برای: headspace solid

تعداد نتایج: 191043  

Journal: :مجله دانشگاه علوم پزشکی قم 0
حمیدرضا حیدری hr heidari qom university of medical sciencesدانشگاه علوم پزشکی قم سید جمال الدین شاه طاهری sj shahtaheri tehran university of medical sciencesدانشگاه علوم پزشکی تهران محمود علیمحمدی m alimohammadi tehran university of medical sciencesدانشگاه علوم پزشکی تهران عباس رحیمی فروشانی a rahimi-froshani tehran university of medical sciencesدانشگاه علوم پزشکی تهران فریده گلبابایی f golbabaei tehran university of medical sciencesدانشگاه علوم پزشکی تهران

background and objectives: analytical methods for volatile organic compounds (vocs) in different samples need extraction of compounds, by applying hazardous solvents. solid phase micro-extraction (spme) is a solvent-free equilibrium extraction method, in which proper calibration can allow quantitative determinations of vocs at a very good sensitivity without the use of any organic solvent. vocs...

Journal: :iranian journal of public health 0
hr heidari dept. of occupational health sj shahtaheri dept. of occupational health, center for environmental research m alimohammadi dept .of environmental health a rahimi-froshani dept. of epidemiology and biostatistics, school of public health, tehran university of medical scien

background: determination of organic pollutants usually requires extraction of the pollutants from samples, using hazard­ous solvent. solid phase micro-extraction (spme) is a solvent-free equilibrium extraction method, in which, proper calibra­tion can allow quantitative measurements of organic pollutants at a very good sensitivity without the use of any organic sol­vent. because individual voc...

Journal: :research journal of pharmacognosy 2014
s. saeidnia z. sepehrizadeh a.r. gohari g. amin a. manayi

dracocephalum kotschyi (lamiaceae), as one of the remarkable aromatic plants, widely grows and also is cultivated in various temperate regions of iran. there are diverse reports about the composition of the oil of this plant representing limonene derivatives as its major compounds. there is no report on cloning of mono- or sesquiterpene synthases from this plant. in the present study, the aroma...

Journal: :Talanta 2005
Tzu-Yun Chu Chau-Chin Hung Chung-Yuan Hsu

A simple and efficient technique that does not require solvent and uses less operating time for the investigation of sex pheromones of the carambola fruit borer (Eucosma notanthes Meyrick) by utilizing headspace solid-phase microextraction (SPME) followed by GC-MS analysis has been developed. Variables such as types of SPME fiber, number of pests, temperature and extraction time have been studi...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2014
mansoor anbia morteza khazaei

in this paper, the possibility of using a new ordered nanoporous carbon as a new fiber in headspace solid phase microextraction (hs-spme) to determine of mononitrotoluenes (mnts) in waste water is demonstrated. the structural order and textural properties of the ordered nanoporous carbon were studied by x ray diffraction (xrd), scanning electron microscopy (sem) images and nitrogen adsorption i...

2000

Compound-specific carbon isotope ratio analysis is a promising tool to assess the origin and fate of organic contaminants in groundwater. The aim of this study was to develop and evaluate a reliable, fast method to determine carbon isotope ratios of chlorinated methanes, ethanes, and ethenes in aqueous samples. Direct solid-phase microextraction (dSPME) and headspace solid-phase microextraction...

Journal: :caspian journal of chemistry 2014
mohammad h fatemi hanieh malekzadeh alireza ghassempour vahide mahdavi

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...

Journal: :Analytical chemistry 2000
Mendes Sparrapan Eberlin

A new MIMS-derived technique, headspace membrane introduction mass spectrometry (HS-MIMS), is described for direct trace level analysis of volatile organic compounds (VOCs) in soil and other dry or wet solid matrixes. A silicone membrane interface is placed about 15 cm from the ion source, and a closed airspace (headspace) is created by connecting a toggle valve to the 1/4 in. tubing that conne...

2004
Derrick C. Wood James M. Miller

2 Headspace sampling for gas chromatographic (GC) analysis has many advantages, the most important of which is the elimination of many interferences from the sample matrix. In addition to the standard methods for headspace sampling, the technique of solid-phase microextraction (SPME) has found wide acceptance because it is simple and inexpensive. More recently, single-drop microextraction (SDME...

Journal: :Molecules 2012
Igor Jerković Dajana Gašo-Sokač Hrvoje Pavlović Zvonimir Marijanović Mirko Gugić Ivana Petrović Spomenka Kovač

GC and MS were used for the analysis of Croatian Centaurium erythraea Rafn essential oil (obtained by hydrodistillation) and headspace (applying headspace solid-phase microextraction). The headspace contained numerous monoterpene hydrocarbons (the major ones were terpinene-4-ol, methone, p-cymene, γ-terpinene and limonene). Oxygenated monoterpenes were present in the headspace and oil, while 1,...

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