نتایج جستجو برای: phase microextraction method hs
تعداد نتایج: 2151476 فیلتر نتایج به سال:
foodstuffs analysis is very important due to population growth and increasing consumer demand for safety and nutritional excellence. the analysis of different compounds in foodstuffs is so difficult without using sample preparation techniques. traditional techniques require large amounts of toxic organic solvents. as a result, they are not only expensive but also environmentally unfriendly and ...
In this study, we compared the fecal microbiota and metabolomes of 26 healthy subjects before (HS) and after (HSB) 2 months of diet intervention based on the administration of durum wheat flour and whole-grain barley pasta containing the minimum recommended daily intake (3 g) of barley β-glucans. Metabolically active bacteria were analyzed through pyrosequencing of the 16S rRNA gene and communi...
During simulation-type biodegradation tests, volatile chemicals will continuously partition between water phase and headspace. This study addressed how (1) this partitioning affects test results and (2) can be accounted for by combining equilibrium partition and dynamic biodegradation models. An aqueous mixture of 9 (semi)volatile chemicals was first generated using passive dosing and then dilu...
Substances classified as unknown or variable composition, complex reaction products biological origin (UVCB) present a challenge for environmental hazard and risk assessment. Here, we novel approach whole-substance bioconcentration testing applied to cedarwood oil—an essential oil composed of volatile, hydrophobic organic chemicals. The method yields whole-body elimination rate constants mixtur...
The sampling techniques headspace solid-phase microextraction (HS-SPME), petrol ether extraction (PEE) and steam distillation extraction (SDE) were compared for the GC-MS of volatile constituents present in ginger (Zingiber officinale). The effects of different parameters, such as extraction fibers, extraction time, extraction temperature and particle size ranges, on the HSSPME of rhizome of gi...
a headspace-solid phase microextraction (hs-spme) and gas chromatography-mass spectrometry (gc-ms) method has been developed for the simultaneously determination of 20 disinfection by-products (dbps) in water samples from reverse osmosis (ro) membranes. selected compounds belong to different families including: trihalomethanes (thms), halogenated acetonitriles (hans), halogenated nitromethanes ...
Thermal treatment of pasteurisation is the most widely used stabilisation method for packed green table olives. In present work, influence on composition volatile compounds in Spanish-style olives was studied. To this aim, two thermal processes (P1 = 85 °C 7 min; P2 15 min) were evaluated by comparing contents pasteurised with those unpasteurised Volatiles analysed, both olive juice and cover b...
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...
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...
A new method is described for the qualitative and quantitative analysis of cyanide, a very short-acting and powerful toxic agent, in human whole blood. It involves the conversion of cyanide into hydrogen cyanide and its subsequent headspace solid-phase microextraction (HS-SPME) and detection by gas chromatography/mass spectrometry (GC/MS) in selected ion monitoring (SIM) mode. Optimizing the co...
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