نتایج جستجو برای: phenols
تعداد نتایج: 11319 فیلتر نتایج به سال:
Antimitotic effects have been reported for several members of the class of compounds which may be described as the simple substituted phenols (Muhling et al., 1960, Hindmarsh 1951, Levan and Tjio 1948, Loveless and Revell 1949, Clowes 1951). Muhling et al. (1960) showed that complex derivatives such as the phenoxyalkyl acids exhibit an effect on mitosis similar to that of the phenols, and sugge...
1-(Hydroxyacetyl)pyrene has been introduced as a new fluorescent phototrigger for alcohols and phenols. Alcohols and phenols were protected as their corresponding carbonate esters by coupling with fluorescent phototrigger, 1-(hydroxyacetyl)pyrene. Photophysical studies of caged carbonates showed that they all exhibited strong fluorescence properties. Irradiation of the caged carbonates by visib...
The performance of isocratic separations of 11 pollutant phenols (PP) using monolithic (Chromolith RP-18e) and conventional reversed-phase 5 microm (Luna and Purospher C18) and 4 microm (Synergi C12) particulate size columns, selected from high purity silica materials, has been compared. The separations have been optimized based on a previously optimized separation in which a reversed-phase C18...
Blueberries are widely valued for their high content in phenolic compounds with antioxidant activity, and hence beneficial for the human health. In this way, a study was done to determine the phenolic composition (total phenols, anthocyanins and tannins) and antioxidant activity of blueberries from three cultivars (Duke, Bluecrop, and Ozarkblue) grown in two different Portuguese farms. Initiall...
A method for the trace level determination of 11 phenols as pentafluorobenzyl (PFB) derivatives by gas chromatography-mass spectrometry (GC-MS) with negative-ion chemical ionization (NICI) is described. First, the conditions for the PFB derivatisation of phenols were optimized and were found to be reaction temperature 80 degrees C and reaction time 5 h. Second, the detection limits using select...
The release of smoke-derived volatile phenols during the fermentation of Merlot grapes, following grapevine exposure to smoke, has been investigated. The concentrations of guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-ethylphenol, and eugenol were determined by gas chromatography-mass spectrometry and found to increase throughout the winemaking process. Only trace levels (< or = 1 microg/L) of...
In studying the anthelmintic properties of certain alkylphenols it became necessary to determine the degree of absorption and excretion of these substances. Although satisfactory quantitative tests for many types of phenols are known and have been reviewed by Gibbs (l), an exhaustive search of the literature failed to reveal any method that was applicable to those p-substituted phenols which ar...
abstract background and objective: stachys inflata benth. is used as an anti-inflammatory and antiseptic agent in traditional medicine in most mountain villages of golestan province. therefore, this study aimed to investigate the antioxidant, ethnopharmacological and phytochemical properties of extract from different parts of s. inflata, collected from chahar bagh mountain. m...
Simultaneous preconcentration of phenol, 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 2-nitrophenol, 4-nitrophenol, and 2,4-dinitrophenol was improved by using olive wood (OW) washed with ethanol then pyrolyzed at 200°C as preconcentrating sorbent. Various OW sorbents were prepared by either washing OW (with ethanol, ether, dichloromethane, tetrahydrofuran or n-hexane); or by pyrolysis (at 1...
A novel high-performance liquid chromatographic method with mass spectrometry and diode array detection method for the simultaneous qualitative and quantitative analysis of bioactive phenols was developed. In total, nine chemically diverse phenols including five bibenzyls, three phenanthrenes and a coumarin were unambiguously identified in Dendrobium aurantiacum var. denneanum by comparison wit...
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