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2.
Chromatographia - The reversed phase behaviour of high molecular mass polystyrenes was investigated on C18 bonded phase columns with ethyl acetate-methanol and ethyl acetateacetonitrile mobile... 相似文献
3.
Summary Fluorescent labelling of cysteine and its homologue homocysteine with monobromobimane followed by TLC on silica gel allows
rapid identification of both compounds through their intense yellow fluorescence when excited at 366 nm; a visual detection
limit of about 2ng is reached for both thiols. 相似文献
5.
An apparatus is devised for development of thin-layer gel chromatograms, which is easy to handle and gives reproducible results even with volatile organic solvent systems. The print technique with a silicone-treated paper can facilitate detection of the samples chromatographed. 相似文献
6.
Considerations of TLC process optimization have been based on the thermodynamic theory of adsorption from multicomponent solvents using experimental and theoretical R M1, 2 = f (Φ 1) relationships. It was found that a relationship exists between the A z parameter (log k where k is the partition coefficient of the substance chromatographed) of the above theory and pK a values of substances as well as the solubility parameter δ of the mobile phase components. Analysis of the A z values of substances shows that a slight variation therein is associated with lower selectivity of chromatographic separation. 相似文献
7.
The effects of different binary solvents on the retention behaviour of some steroids in thin-layer chromatography on alumina were studied. The slope of the linear relationship between the retention constant of the steroid and the logarithm of the volume fraction fo the polar component in the binary solvent mixture depends predominantly on the diluent. Linear relationships between the axis intercepts and slopes of particular steroids exists for all chromatographic systems examined. The slope of this relationships is a function of the retention constant of the steroid hydroxyl group. 相似文献
8.
Summary The reversed phase behaviour of high molecular mass polystyrenes was investigated on a C18 bonded phase column using acetonitrile
as the polar mobile phase component and dichloromethane, chloroform and carbon tetrachloride, as separate nonpolar components.
Solvent solubility compositions, elution compositions and resolutions of the various molar mass polystyrenes were measured
and compared for each of the three mobile phases. Anomalous behaviour of the polystyrenes was not observed in any of the three
mobile phases and only minor differences in resolution were observed. By comparing these results with previously published
work, it is suggested that any mobile phase component that is both nonpolar and a good solvent for the polymer can be combined
with acetonitrile for effective separations of polystyrenes by mass and that it is the poor solvent component of the mobile
phase that is responsible for the anomalous behaviour that is sometimes observed in this type of chromatography. 相似文献
12.
A spectrodensitometric method is described for the determination of the components of two analgesic mixtures. For the first mixture (paracetamol-ascorbic acid-caffeine-phenylephrine), the pharmaceutically active components were separated from each other and closely related degradation products and impurities on high-performance thin-layer chromatography (F254) plates using methylene chloride-ethyl acetate-ethanol-formic acid (3.5 + 2 + 4 + 0.5) and methylene chloride-ethyl acetate-ethanol (5 + 5 + 1) as the developing systems. The other mixture (phenazone-phenacetin-caffeine) was separated efficiently from the degradation products using the same plates and acetonitrile-chloroform (1 + 1) as the mobile phase. The proposed method was used to determine these mixtures in commercial tablets. 相似文献
13.
Secondary-ion mass spectrometry (SIMS) is used to sputter ions directly from thin-layr chromatograms in which components in a mixture have been separated. Mixtures of phenothiazine drugs and small peptides have been separated an detected by the chromatography/SIMS method. Phosphonium salts have been separated by thin-layer chromatography and imaged in situ by mass spectrometer. Organometallic compounds such as the transition metral acetylacetonates have been simialry determined. Mixtures that have been separated by gel electrophoresis are transferred by using a standard blotting procedure to a nitrocellulose support, which is then examined by secondary-ion mass spectrometry. A mixture of organic dyes was separated by gel electrophoresis, and characterized by secondary-ion mass spectrometry. The use of the mass spectral information to deconvolute overlapping components on the chromatogram is discussed, and the ultimate spatial resolution for molecular mapping is estimated as about 1 μm. 相似文献
14.
Reproducible R f values in the thin-layer chromatography (TLC) of various fluorescent dyes (amino derivatives of naphthoylenebenzimidazole, naphthalimide, benzanthrone, phenalenone, including phosphorus-containing luminophores) were shown to be obtained by elution with binary homogeneous azeotropic mixtures of solvents of different polarity. Some trends in the chromatographic mobility were established governed by the structural features of the groups of compounds under study. 相似文献
16.
Summary The use of a binary solvent mixture (nitromethane/benzene) is shown to result in an improved separation of the polyiodides of the entire alkali group on thin-layers of air-most silica gel.
Zusammenfassung Die Verwendung eines binären Lösungsmittelgemisches (Nitromethan-Benzol) führt zu einer verbesserten Trennung der Polyjodide der ganzen Alkaligruppe auf luftfeuchten Silikagel-Dünnschichten.
Undergraduate Research Participant, State University of New York at Binghamton, 1966. 相似文献
17.
Developing fit-to-purpose analytical screening methods for plant marker constituents by simple and affordable techniques represents a constant and important request from the current transformation chain of plant products. In this work, methods developed on classical thin-layer chromatography (TLC) and overpressured layer chromatography (OPLC) have been applied on some of the most valuable commercial plant products, such as star anise (Illicium verum Hook. f.) essential oil and extracts, common thyme (Thymus vulgaris L.) and sweet fennel (Foeniculum vulgare Mill.) essential oils and acerola fruit (Malpighia punicifolia L.) hydroalcoholic extracts, to evaluate OPLC potentiality in comparison with TLC performances in the detection of some characteristic constituents. OPLC provided higher performance with respect to TLC in all experiments performed due to higher selectivity demonstrated on all the tested marker compounds except for flavonoids in acerola extracts. Considering the usage of planar chromatography in the quality control of plant derivatives, the present paper shows how the OPLC protocols were both highly time- and solvent-saving in comparison with classical TLC. 相似文献
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