نتایج جستجو برای: headspace
تعداد نتایج: 2540 فیلتر نتایج به سال:
The isolation of ignitable liquid components, usually petroleum-based distillates from fire debris, is an important step in deciding whether a fire is of natural or incendiary origin. Steady progress has been made to develop sample preparation methods capable of enriching target analytes in high yield and within a short period of time. Heated headspace enrichment methods are currently most wide...
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...
Resonance-enhanced multiphoton ionization (REMPI) is investigated as a potential technique for real-time monitoring of selected volatile organochloride compounds (VOCs). In a proof-of-concept experiment, the progress of the reductive-degradation of tetrachloroethylene (PCE) to trichloroethylene (TCE) by zero-valent zinc was monitored by REMPI measurements performed in the headspace above the PC...
Herein, we report on the results of solventand sorbent-free HS-GC-MS (headspace – gas chromatography – mass spectrometry) analysis of the headspace volatiles (HSVs) of fruits of cultivated melon (Cucumis melo L. cultivar “ananas dinja” [pineapple melon]) and pear (Pyrus communis L. cultivar “Julska lepotica” [the beauty of July]), as well as of underground parts of carrot (Daucus carota L. cult...
In this study a headspace spectrophotometric method is proposed for analysis of dichloromethane and isobutyl methyl keton (IBMK) residues in the ampicillin powder. Ampicillin is dissolved in 1 M NaOH in the vessel of an arsenic analyzer unit of an atomic absorption spectrophotometer. After 3-min stirring, the headspace has flowed by air into the flow-through cell and its absorbance is read at 1...
A new method for rapid sampling and qualitative characterization of the headspace gases of closed in vitro cultures using solid phase microextraction (SPME) was evaluated for ruminal fluid and ruminal fluid with feed containing a feed additive. Gas sample collection was achieved by exposing a DVB/Carboxen/PDMS 50/30 m SPME fiber to the headspace of cultures for 1 min every hour. This was follow...
A test method of methanol content in detergent using a headspace-GC method was established. A 1 g aliquot of test sample was mixed with 0.4 mg of 2-propanol and made up to 20 mL with water. Then, 5 mL of test solution was placed in a headspace vial. The vial was sealed and incubated for 30 min at 60°C, then the headspace gas was analyzed by GC-FID. The recovery from spiked 1 mg/g of methanol wa...
Smokeless powder additives are usually detected from an extraction of post-blast residues or unburned powder particles followed by chromatographic analyses. This work presents the first comprehensive study of the detection of volatile and semi-volatile additives of smokeless powders using solid phase microextraction (SPME) as a sampling and pre-concentration technique. The goal of this study is...
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