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A HPLC method with DAD detection for determination of melatonin in Lamium album flos was developed. The analysis was carried out on RP18 column using mixture of methanol and water (28:72 v/v) as a mobile phase. Established calibration curve (r>0.9994), precision (RDS values ranged from 0.5% to 1.5%), detection limit (0.025 μg/mL) and quantification limit (0.076 μg/mL) were found to be satisfactory for the proposed method. The determined content of melatonin in Lamium album flos was 0.15 μg/g of dry plant material.
The aim of our study was to investigate the presence and quantitative contents of lignans in the tissues of Taxus ×media. The presence of the lignans: pinoresinol, matairesinol and secoisolariciresinol was assessed in needles, shoots cultures and suspension culture. Pinoresinol was the only lignan found in the tissue of T. ×media. The total pinoresinol content in the needles and in the shoots was 1.24 mg/g dry weight (dw) and 0.69 mg/g dw, respectively. Most of the pinoresinol identified was appeared glycosidically bound. In needles, the amount of glycosidically bound pinoresinol (0.81 mg/g dw) was about twice as high as that of free pinoresinol (0.43 mg/g dw). The content of free and glycosidically bound pinoresinol showed the level of 0.18 mg/g dw and 0.51 mg/g dw, respectively in the in vitro shoot cultures. In the cell culture, no pinoresinol was found.
The aim of this study was to present a new analytical method for the quantitative determination of metallothioneins (MT) protein in human body fluids and tissues, in order to determine the level of environmental and industrial exposition to heavy metals. For MTs isolation covalent affinity chromatography with thiol-di- sulphide interchange (CAC-TDI) was applied, which is a modern technique of separation of a high affinity, good repeatability and reproducibility, allowing specific isolation of the thiolproteins and metallothiolproteins. Fundamentals of indirect determination of the contents of metallothioneins protein were worked out throught estimation of the quantities of metals bound with metallothionein protein and adsorbed on covalent affinity chromatography gel as on solid-phase extraction support during a separating process. The (CAC-TDI) gel, specially prepared, was used as a solid phase extraction support (SPE) for preconcent- ration of Hg-Thionein (Hg-Th), Cd-thionein (Cd-Th), Zn-thionein (Zn-Th) and Cu-thionein (Cu-Th) proteins and Hg, Cd, Zn and Cu bonded with MTs from spiked water, urine, human plasma, breast milk and tissues' homogenates.
In the centaury herb collected from natural sites in eastern Poland the total content of flavonoids (0.28%), phenolic acids (2.50%) and tannins (1.25%) were determined. From the methanol extract of the raw material four flavonoid compounds were isolated and identified as quercetin 3,3'-dimethylether, kaempferol 3-0-neohesperidoside, isorhamnetin 3-0-glucoside and kaempferol 3-0-rhamnoside-7-0-rutinoside. The last-mentioned compound seems to be a unique one. On the basis of GC of isolated fractions of free phenolic acids and those revealed after alkaline and acid hydrolysis, thirteen phenolic acids were identified. In the fraction of free phenolic acids the main compounds were: protocatechuic, vanillic, p-hydroxybenzoic, m-hydroxybenzoic and syringic acids. In the fraction obtained after alkaline hydrolysis the dominant acids were p-hydroxybenzoic and p-coumaric one. The first one was also the principal acid among those revealed after acid hydrolysis.
An analytical method for the simultaneous determination of tetracycline (TC), oxtetracycline (OTC), chlortetracycline (CTC) with their 4-epimers, and doxycycline (DC) in animal tissues has been developed and validated. The extraction of the analytes from biological matrice was carried out with a 0.02 M oxalic acid (pH=4.0). The samples were cleaned up by using a solid phase extraction procedure with polymeric cartridges. Chromatographic separation was achieved on a C 18 analytical column using a mobile phase consisting of acetonitrile, methanol and 0.02 M oxalic acid in gradient mode. Detection was carried out by UV detector at λ = 355 nm. The method has been validated according to the Commission Decision 2002/657/EC. The recoveries of the analytes from the spiked samples were 50%-80%. The decision limits (CCα) were from 110 to 125 µg/kg and the detection capabilities (CCß) were from 120 to 155 µg/kg, depending on the analytes. The prepared method was successfully verified in the National Residue Control Programme.
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