نتایج جستجو برای: headspace sampling
تعداد نتایج: 214473 فیلتر نتایج به سال:
This preliminary study presents a new method for the determination of dissolved gases in sea-water. After headspace extraction, gaseous compounds are separated by GC on a dual column adsorption system. The individual species are thereafter eluted to three different detectors (thermal conductivity, flame ionization and FPD) using a second switching valve. The analysis is quantitative for methane...
Commonly used dynamic sorption techniques for collecting biologically active volatile compounds have been compared. Solid phase microextraction (SPME) using two types of fibers (polydimethylsiloxane, PDMS, 100 microm, and carbowax/divinylbenzene, CW/DVB, 65 microm) was compared to purge and trap methods (Porapak Q, Tenax TA and charcoal) and a technique based on absorption in methanol in a cool...
Furan is naturally occurring at low levels in many foods and drinks.1 Furan consumption is of concern because it has been classified by the International Agency for Research on Cancer (IARC) as possibly carcinogenic to humans, based on studies with laboratory animals. The U.S. FDA has recently published a report on the occurrence of furan in a large number of thermally processed foods, especial...
OBJECTIVES To provide the first national profile of the characteristics of young people (aged 12-25 years) accessing headspace centre services - the Australian Government's innovation in youth mental health service delivery - and investigate whether headspace is providing early service access for adolescents and young adults with emerging mental health problems. DESIGN AND PARTICIPANTS Census...
The extraction and quantitative analysis of low molar mass compounds in polymers is an analytical challenge. It is also important from a practical point of view because the low molar mass compounds in time will migrate from the polymers into the surrounding environment. It is especially important to gain knowledge about the migrating compounds in applications such as medical implants, packaging...
Honey volatiles exhibit a potential role in distinguishing honeys as a function of botanical origin, but heating of honey generates artefacts such as compounds of Strecker degradation and Maillard reaction products. This short review is focused on the most recently applied methods for honey volatiles fingerprinting (without generation of thermal artefacts): headspace extraction (dynamic headspa...
Headspace solid-phase microextraction (HS-SPME) and ultrasonic solvent extraction (USE), followed by GC-MS/FID, were applied for monitoring the nectar (NE)/honey-sac (HoS)/honey (HO) pathways of the headspace, volatiles, and semi-volatiles. The major NE (4 varieties of Citrus unshiu) headspace compounds were linalool, α-terpineol, 1H-indole, methyl anthranilate, and phenylacetonitrile. Correspo...
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...
Headspace sampling-gas chromatography (HS-GC) coupled with an internal standard method (ISM) was developed to analyze the volatile flavor compounds in top fermented wheat beer in the laboratory. Eight compounds, i.e. acetaldehyde, N-propanol, ethyl acetate, isobutyl alcohol, isoamyl alcohol, isoamyl acetate, ethyl hexanoate and ethyl octanoate were separated and quantified. This method was vali...
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