نتایج جستجو برای: polar compounds
تعداد نتایج: 268855 فیلتر نتایج به سال:
Hydrophilic interaction chromatography (HILIC) for LC-MS/MS analysis of monoamine neurotransmitters.
BACKGROUND Hydrophilic interaction chromatography (HILIC) is becoming an increasingly popular alternative to traditional reversed-phase chromatography for the analysis of polar compounds. The ability to retain the most polar compounds in HILIC makes it attractive for the analysis of certain large groups of compounds, such as monoamines, which are inherently very polar. RESULTS This paper deta...
and Yan (5) reported that they successfully separated high polarity explosives using CEC with nonporous C18-coated material and a mobile phase with a low concentration of organic modifier and SDS added to the mobile phase to increase the wettability of the particle surface. Zhang and colleagues (9) also reported that very polar compounds could be separated by mixed-packing CEC with a stationary...
The electronic structure and spectra of 3-formylchromone and some of its derivatives are investigated using TD-DFT/B3LYB/6-311G (d, p) level of theory. The results of calculations show that all the studied compounds 1–6 are planar, as indicated from the dihedral angles. The electronic absorption spectra of the studied compounds are recorded in the UV-Vis region, in both ethanol (as polar solven...
A variety of extraction procedures were evaluated for the extraction of arsenic and other analytes from lobster tissue samples using inductively coupled plasma mass spectrometry (ICP-MS) detection. Soxhlet, room temperature mixing, sonication, microwave assisted, supercritical carbon dioxide and subcritical water extractions were evaluated for a variety of solvent systems and optimum conditions...
Residues of 37 polar veterinary drugs belonging to six families (quinolones, tetracyclines, macrolides, lincosamides, sulfonamides, and others) in livestock and fishery products were determined using a validated LC-MS/MS method. There were two key points in sample preparation. First, extraction was performed with two solutions of different polarity. Highly polar compounds were initially extract...
Introduction: In this study, Antibacterial and antioxidant activities of the essential oil and methanolic extract of the endemic plant, Zataria multiflora Boiss. have been studied. Method: The antioxidant potential of the samples was evaluated using two separate methods of inhibition of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ammonium thiocyanate systems. Antibacterial activity wa...
BACKGROUND The plant cuticle is an extracellular lipophilic biopolymer covering leaf and fruit surfaces. Its main function is the protection of land-living plants from uncontrolled water loss. In the past, the permeability of the cuticle to water and to non-ionic lipophilic molecules (pesticides, herbicides and other xenobiotics) was studied intensively, whereas cuticular penetration of polar i...
deproteinisation with acetonitrile (along with methanol or other reagents) is a useful and rapid technique in analysis of drugs or their metabolites in human serum. in this paper application of this simple technique in biopharmaceutical analysis using capillary electrophoresis (ce) is evaluated. some drugs with different ionic and protein binding properties were selected and dissolved in human ...
derivatives of pyridine-4-one are iron chelators with various biological activities including antifungal, anti-malarial, antiviral, anti-inflammatory and analgesic activities. this study was aimed to evaluate the analgesic effect of four new derivatives of 3-hydroxy pyridine-4-one in animal models. acetic acid-induced writhing and formalin tests were used to assess the analgesic activity in mal...
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