نتایج جستجو برای: microextraction

تعداد نتایج: 3012  

2015
Josias Merib Adriana N. Dias Vanessa Simão

A new single-drop microextraction approach is proposed for the extraction of compounds with a wide range of volatilities from tap water samples with separation/detection by gas chromatographymass spectrometry. This new microextraction mode is called direct immersion-headspace-single drop microextraction (DI-HS-SDME). Trihalomethanes (THMs), hydrocarbons with low molecular weight (benzene, ethyl...

Journal: :Clinical chemistry 2006
Florin Marcel Musteata Mihaela L Musteata Janusz Pawliszyn

BACKGROUND We sought to develop a technique with the potential to partly replace current methods of analysis based on blood draws. To achieve this goal, we developed an in vivo microextraction technique that is faster than conventional methods, interferes minimally with the investigated system, minimizes errors associated with sample preparation, and limits exposure to hazardous biological samp...

A Mohammadi, F Barzegar, M Kamankesh, N Omidi,

Background and Objectives: Heterocyclic aromatic amines (HAAs) are carcinogenic and mutagenic substances, which are formed during the heating process of proteinaceous foods such as meat and meat products. The extraction of these compounds from the complex matrix of meat products was carried out by microwave assisted pre-extraction and a precise, rapid and high sensitive microextraction method. ...

Journal: :Journal of forensic sciences 2000
J R Almirall J Wang K Lothridge K G Furton

A simple, fast, inexpensive, and sensitive technique for the detection and identification of flammable or combustible liquid residues on the skin of arson suspects is presented. The use of solid phase microextraction (SPME) for the analysis of ignitable liquid residues has been demonstrated and it is shown in this work that this technique is effective in extracting these liquid residues at extr...

Journal: :Journal of chromatography. A 2004
Mari R Tellez Ikhlas A Khan Brian T Schaneberg Sara L Crockett Agnes M Rimando Mozaina Kobaisy

A new method involving concurrent solid-phase microextraction combined with continuous hydrodistillation of essential oil was developed. This new methodology allowed for the detection by GC-MS of very small amounts of a diagnostic peak for the authentication of Ephedra sinica, in a short period of time and using only small sample sizes. This diagnostic peak was identified as 4-vinylanisole, and...

2017
Grażyna Wejnerowska

A single-drop microextraction (SDME) was developed for the analysis of volatile fatty acids (VFAs) (C2-C7) in water by gas chromatography (GC) with flame ionization detection. The significant parameters affecting the SDME performance such as selection of microextraction solvent, extraction time, stirring rate, sample pH and temperature, and ionic strength were studied and optimized. To lower li...

2006
K. Luks-Betlej D. Bodzek

Trihalomethanes (methane derivatives containing chlorine and/or bromine) have been determined in drinking waters in Upper Silesia the most industrious and most populated region in Poland. Halomethane content determination is based on Capillary Gas Chromatography (CGC) with Electron Capture Detector (ECD), while these compounds' isolation from waters by Solid-Phase Microextraction (SPME) is base...

Journal: :Analytical and bioanalytical chemistry 2009
Amy R Stefan Christopher R Dockery Brittany M Baguley Brandi C Vann Alexander A Nieuwland James E Hendrix Stephen L Morgan

Designed experiments based on a simplex mixture design were employed to explore the effects of three solvent components (water, formic acid, and aqueous acetic acid), extraction time, and extraction temperature for the automated microextraction of basic (cationic) dyes from acrylic fibers. Extractions were conducted by an automated liquid handling system, and dye extraction was evaluated using ...

2009
Ali Sarafraz-Yazdi Amirhassan Amiri

The development of faster, simpler, inexpensive and more environmentally-friendly sample-preparation techniques is an important issue in chemical analysis. Recent research trends involve miniaturization of the traditional liquid-liquid-extraction principle by greatly reducing the acceptor-to-donor ratio. The current trend is towards simplification and miniaturization of sample preparation and d...

Journal: :Journal of the American Ceramic Society. American Ceramic Society 2015
Robert F Cook

Multiple length-scale effects are demonstrated in indentation-strength measurements of a range of ceramic materials under inert and reactive conditions. Meso-scale effects associated with flaw disruption by lateral cracking at large indentation loads are shown to increase strengths above the ideal indentation response. Micro-scale effects associated with toughening by microstructural restraints...

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