نتایج جستجو برای: headspace sampling
تعداد نتایج: 214473 فیلتر نتایج به سال:
A multi purpose sampler (Gerstel MPS), designed for liquid large volume, gaseous and headspace samples was tested for its suitability in the GC-MS analysis of organic volatiles in human urine. Headspace sampling with a volume, temperature and speed controlled gas tight syringe was combined with a temperature controlled cold injection system for cold trapping, enrichment and focussing of analyte...
An uncertainty budget was constructed for the measurement of ethanol in blood by headspace gas chromatography. The uncertainty budget, covering the analytical range of ethanol concentrations up to 3.00 g/kg, included analytical uncertainty components, traceability uncertainty components, and effects caused by interindividual variation in blood water content. The analytical combined standard unc...
The introduction of legislation to control driving under the influence o f alcohol has led to the development and use of a number of instrumental methods for measuring the concen tration of alcohol in body fluids.11 Standard methods for blood and urine analysis, based mainly on gas chromatography, are in common use and under laboratory conditions can give results with standard deviations of be...
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,...
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...
Biohydrogen production is measured using a variety of techniques, ranging from low cost intermittent gas release methods where yields are usually reduced due to high partial pressures of hydrogen, to expensive respirometers that can eliminate pressure buildup. A new large headspace volume technique was developed that reduces the potential for hydrogen gas inhibition without the need for a respi...
Equilibration time and temperature were the factors studied to choose the best conditions for analyzing volatiles in roasted ground Arabica coffee by a static headspace sampling extraction method. Three temperatures of equilibration were studied: 60, 80, and 90 degrees C. A larger quantity of volatile compounds was extracted at 90 degrees C than at 80 or 60 degrees C, although the same qualitat...
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