Showing papers on "Thin-layer chromatography published in 1987"
TL;DR: The family pedigree suggested that abnormal bile acid synthesis was an autosomal recessive condition leading to cirrhosis in early childhood, and it was supported by analysis using fast atom bombardment mass spectrometry.
Abstract: Urinary bile acids from a 3-mo-old boy with cholestatic jaundice were analyzed by ion exchange chromatography and gas chromatography-mass spectrometry (GC-MS). This suggested the presence of labile sulfated cholenoic acids with an allylic hydroxyl group, a conclusion supported by analysis using fast atom bombardment mass spectrometry (FAB-MS). The compounds detected by FAB-MS were separated by thin layer chromatography and high performance liquid chromatography. The sulfated bile acids could be solvolyzed in acidified tetrahydrofuran, and glycine conjugates were partially hydrolyzed by cholylglycine hydrolase. Following solvolysis, deconjugation, and methylation with diazomethane, the bile acids were identified by GC-MS of trimethylsilyl derivatives. The major bile acids in the urine were 3 beta,7 alpha-dihydroxy-5-cholenoic acid 3-sulfate, 3 beta,7 alpha,12 alpha-trihydroxy-5-cholenoic acid monosulfate, and their glycine conjugates. Chenodeoxycholic acid and cholic acid were undetectable in urine and plasma. The family pedigree suggested that abnormal bile acid synthesis was an autosomal recessive condition leading to cirrhosis in early childhood.
175 citations
TL;DR: The results and the data in the literature are compatible with the hypothesis that 2-EPA is absorbed with minimum hydrolysis and escapes random distribution between the other positions of the glycerol molecule during the absorption process.
Abstract: After administering the equivalent of 1 g of eicosapentaenoic acid (EPA) in four different chemical forms, the kinetics of EPA incorporation into plasma triglycerides (TG) were compared by gas liquid chromatography on a capillary column following separation of the lipid fraction by thin layer chromatography. EPA incorporation into plasma TG was markedly smaller and later when EPA was administered as an ethyl ester rather than as EPA free fatty acid, EPA arginine salt or 1,3-dioctanoyl-2-eicosapentaenoyl glycerol (2-EPA). Our results and the data in the literature are compatible with the hypothesis that 2-EPA is absorbed with minimum hydrolysis and escapes random distribution between the other positions of the glycerol molecule during the absorption process.
171 citations
TL;DR: It was found that at pH values at which no significant de-O-acetylation is observed, Neu 5,7Ac2 can easily be transformed into Neu5,9Ac2, and Neu4,5Ac2 does not give rise to O-acety migrations.
Abstract: Highly purified N-acetyl-4-O-acetylneuraminic acid (Neu4,5Ac2), N-acetyl-7-O-acetylneuraminic acid (Neu5,7Ac2) and N-acetyl-7,9-di-O-acetylneuraminic acid (Neu5,7,9Ac3) were used to study spontaneous migrations of acetyl groups between hydroxyl groups. The techniques applied involved thin-layer chromatography, gas-liquid chromatography/mass spectrometry, high-performance liquid chromatography and 360-MHz 1H-NMR spectroscopy. It was found that at pH values at which no significant de-O-acetylation is observed: (a) Neu5,7Ac2 can easily be transformed into Neu5,9Ac2, (b) Neu5,7,9Ac3 yields an equilibrium of Neu5,7,9Ac3 and Neu5,8,9Ac3 in a molar ratio of approximately 1:1, and (c) Neu4,5Ac2 does not give rise to O-acetyl migrations. The importance of these findings is discussed in terms of the biosynthesis of O-acetylated sialic acids.
143 citations
TL;DR: It is shown that phosphatidylcholines containing the novel fatty acids are highly concentrated in photoreceptor membranes and that they occur in the retina of vertebrates so distant in evolution as fish, birds, and various mammals.
131 citations
114 citations
TL;DR: Aqueous acetone extracts of leaves from ten browse plants were examined by high performance liquid chromatography and thin layer chromatography for their phenolic constituents as mentioned in this paper, and Flavan-3-ols, flavonols, and flavonol glycosides were characterised and identified together with gallic, ellagic and chlorogenic acids.
Abstract: Aqueous acetone extracts of leaves from ten browse plants were examined by high performance liquid chromatography and thin layer chromatography for their phenolic constituents. Flavan-3-ols, flavonols and flavonol glycosides were characterised and identified together with gallic, ellagic and chlorogenic acids. Condensed and hydrolysable tannins were also detected.
Trans-and cis-p-coumaric and trans-ferulic acids were identified after alkaline hydrolysis of the browse leaves. The content of these acids was high in plants with the lowest tannin contents.
92 citations
Journal Article•
TL;DR: Phenolic compounds in 21 grape cultivars grown in New York during the 1985 season were analyzed by using column chromatography, thin layer chromatography and high performance liquid chromatography as discussed by the authors.
Abstract: Phenolic compounds in 21 grape cultivars grown in New York during the 1985 season were analyzed by using column chromatography, thin layer chromatography, and high performance liquid chromatography. Trans-caffeoyl tartaric acid, cis-coumaroyl tartaric acid, and trans-coumaroyl tartaric acid were the major components of acidic phenolics, while catechin, epicatechin, and two unidentified compounds were the major constituents in the neutral phenolics. One of the unidentified compounds was tentatively identified as a catechin-gallate and the others as isomers of catechin-catechin-gallate. There were large differences in the phenolic make-up of the individual cultivars. Mean values of individual phenolics were higher in the New York grapes than in those from the western United States and Europe.
85 citations
26 Jun 1987
TL;DR: In this paper, a 3-mo-old boy with cholestatic jaundice was analyzed by ion exchange chromatography and gas chromatography-mass spectrometry (GC-MS), which suggested the presence of labile sulfated cholenoic acids with an allylic hydroxyl group.
Abstract: Urinary bile acids from a 3-mo-old boy with cholestatic jaundice were analyzed by ion exchange chromatography and gas chromatography-mass spectrometry (GC-MS). This suggested the presence of labile sulfated cholenoic acids with an allylic hydroxyl group, a conclusion supported by analysis using fast atom bombardment mass spectrometry (FAB-MS). The compounds detected by FAB-MS were separated by thin layer chromatography and high performance liquid chromatography. The sulfated bile acids could be solvolyzed in acidified tetrahydrofuran, and glycine conjugates were partially hydrolyzed by cholyglycine hydrolase. Following solvolysis, deconjugation, and methylation with diazomethane, the bile acids were identified by GC-MS of trimethylsilyl derivatives. The major bile acids in the urine were 3β,7α-dihydoxy-5-cholenoic acid 3-sulphate, 3β,7α,12α-trihydroxy-5-cholenoic acid monosulfate, and their glycine conjugates. Chenodeoxycholic acid and cholic acid were undetectable in urine and plasma. The family pedigree suggested that abnormal bile acid synthesis was an autosomal recessive condition leading to cirrhosis in early childhood.
75 citations
TL;DR: The major metabolites of the phosphatidylinositol cycle from extracts of extracts of [(32)PO(4)]- and [(3)H]- inositol-labeled Samanea saman pulvini appear to have a variant profile.
Abstract: The major metabolites of the phosphatidylinositol cycle from extracts of [32PO4]- and [3H]-inositol-labeled Samanea saman pulvini were separated. The membrane localized phosphoinositides were separated by thin layer chromatography, identified by comparison with purified lipid standards, and quantitated based on incorporation of radiolabel. The ratio of radioactivity in phosphatidylinositol:phosphatidylinositol 4-phosphate:phosphatidylinositol 4,5-bisphosphate is about 32:8:1. The aqueous inositol phosphates were separated by anion exchange chromatography using conventional liquid chromatography and by high performance liquid chromatography (HPLC) and were identified by comparison with standards. Analysis by HPLC reveals that 32P-labeled pulvini have inositol 1-phosphate, inositol 1,4-bisphosphate, and inositol 1,4,5-trisphosphate that co-migrate with red blood cell inositol phosphates, but 3H-inositol-labeled pulvini appear to have a variant profile.
69 citations
TL;DR: In this paper, a reversed phase high performance liquid chromatography has been used and results confirmed for the more concentrated compounds by thin-layer chromatography on silica gel.
TL;DR: X-ray diffraction analysis indicated that the in vitro product is cellulose II, which is in contrast to the in vivo product—namely, cellulose I, and the weight-average and number-average degree of polymerization of the in embryos product were 4820 and 5270, respectively.
Abstract: The cytoplasmic and outer membranes of Acetobacter xylinum (ATCC 53582) were isolated by discontinuous sucrose density ultracentrifugation. Both lysozyme (EC 3.2.1.17) and trypsin (EC 3.4.21.4) were required for efficient crude membrane separation. Primary dehydrogenases and NADH oxidase were used as cytoplasmic membrane markers, and 2-keto-3-deoxyoctulosonic acid was used to identify the outer membranes. Cellulose synthetase (UDP-glucose:1,4-β-D-glucan 4-β-D-glucosyltransferase; EC 2.4.1.12) activity was assayed as the conversion of radioactivity from UDP-[14C]glucose into an alkali-insoluble β-1,4-D-[14C]glucan. This activity was predominantly found in the cytoplasmic membrane. The cellulose nature of the product was demonstrated by (i) enzymatic hydrolysis followed by TLC, (ii) methylation analysis followed by TLC, and (iii) GC/MS. Further, the weight-average and number-average degree of polymerization of the in vitro product, determined by high-performance gel permeation chromatography, were 4820 and 5270, respectively. In addition, x-ray diffraction analysis indicated that the in vitro product is cellulose II, which is in contrast to the in vivo product—namely, cellulose I.
TL;DR: Surface-Enhanced Resonance Raman Spectra of Adriamycia, 11-Deoxycar minomycin, Their Model Chromophores, and Their Complexes with DNA is used to determine Purine Bases by Reversed-Phase High Performance Liquid Chromatography Using Real-Time Surface-Enhanced.
Abstract: T. W. Graham Solomms, Organic Chemistry, John Wiley & Sons 1980. Theodora W. Greene, Protective Groups In Organic Synthesis, John Wiley & Sons 1981. Giulietta Smulevich et al. \"Surface-Enhanced Reso nance Raman Spectra of Adriamycia, 11-Deoxycar minomycin, Their Model Chromophores, and Their Complexes with DNA\" Journal of Physical Chemistry, vol. 90, No. 23 (1986) 6388-6392. Therese M. Cotten et al. \"Determination of Purine Bases by Reversed-Phase High Performance Liquid Chromatography Using Real-Time Surface-Enhanced
TL;DR: It is shown that platelet-activating factor is present in unstimulated liver and that its detection is masked by an endogenous lipid-like inhibitor.
TL;DR: The diastereomers were formed and hydrolysed, by dilute HCl spray, on the chromatogram only and the amino acids thus resolved were located by ninhydrin spray.
Abstract: Resolution of enantiomeric mixtures of DL-amino acids (Nine) using silica gel layers impregnated with (-)-bruncine is reported. The solvent system used was Butanol: Acetic acid: Chloroform (3∶1∶4). The diastereomers were formed and hydrolysed, by dilute HCl spray, on the chromatogram only and the amino acids thus resolved were located by ninhydrin spray. The cross resolution possibilities of enantiomers were also calculated.
TL;DR: New solvent systems consisting of acetonitrile, isopropanol and aqueous 50 mM potassium chloride or 2.5 M ammonium hydroxide seem to be superior for the resolution of polysialogangliosides such as tetra-, penta- and hexasialo species, as compared to chloroform-methanol-aqueous salt systems.
TL;DR: In this article, the reversed phase liquid chromatographic retention behavior of chlorophylls, pheophytins, and pheophorbides was studied on an octadecyl-bonded stationary phase with mobile phase solvents of different polarities, including alcohols, acetone, acetonitrile and mixtures of ethanol and water.
TL;DR: The shed skins of 23 species of lizards (12 families) soaked in chloroform:methanol solutions gave extracts ranging from 1.4 to 10.8% of their weight as mentioned in this paper.
Abstract: 1. 1. The shed skins of 23 species of lizards (12 families) soaked in chloroform:methanol solutions gave extracts ranging from 1.4 to 10.8% of their weight. 2. 2. The polar and nonpolar lipid fractions were separated by silicic acid and subjected to thin-layer chromatography (TLC) with known lipid standards to allow tentative identification of the skin constituents. 3. 3. All lizards contain TLC bands consistent with sterols, free fatty acids, and sterol esters. 4. 4. Phosphatidylcholine and phosphatidylethanolamine were present in the polar lipid fraction of most species, but the bulk of the polar lipids consisted of compounds less polar than phosphatidylethanolamine.
TL;DR: These assay methods are found to be particularly pertinent and useful in providing a more comprehensive metabolic profile of diazepam metabolism, especially when aromatic hydroxylation pathways predominate.
TL;DR: An overview of analytical methodology for the determination of organophosphate pesticides residues in foods is presented and thin-layer chromatography with enzyme inhibition detection can be used as a rapid screening technique or to confirm results obtained by gas chromatography.
Abstract: An overview of analytical methodology for the determination of organophosphate pesticides residues in foods is presented. Sample extraction is carried out with acetone followed by a dichloromethane-hexane partition. The organic extract is purified by automated gel permeation chromatography and analysed by capillary gas chromatography with flame photometric or thermionic detection. Confirmation can be carried out by a variety of chemical derivatization techniques including hydrolysis followed by reaction of the phosphate or phenol moiety, direct alkylation or trifluoracetylation. Thin-layer chromatography with enzyme inhibition detection can be used as a rapid screening technique or to confirm results obtained by gas chromatography. Liquid chromatography has not been used much for the determination of organophosphorus compounds in foods.
TL;DR: Sufficient separation for the subsequent ozonolysis and chromatographic quantification of isomeric C18 and C22 fatty acid methyl esters is obtained with both methods.
Abstract: This paper describes novel and rapid thin-layer chromatography procedures for the analysis of fatty acids and methyl esters using silver-impregnated alumina sheets. These techniques are known in most laboratories, and the equipment is readily available. The fatty acid method allows a separation of petroselinic (C18:1 delta 6c), oleic (C18:1 delta 9c), elaidic (C18:1 delta 9t), erucic (C22:1 delta 13c), and brassidic acids (C22:1 delta 13t), and the methyl ester method gives an excellent resolution with respect to the number, configuration, and position of the unsaturated centers. Sufficient separation for the subsequent ozonolysis and chromatographic quantification of isomeric C18 and C22 fatty acid methyl esters is obtained with both methods.
TL;DR: For quantitative trace metal analyses, a great number o f established methods are available nowadays as discussed by the authors, such as atomic absorption spectrometry, plasma emission spectrometer, and X-ray fluorescence analysis.
Abstract: For quantitative trace metal analyses a great number o f established methods are available nowadays. Efficient spectroscopic determination methods like atomic absorption spectrometry, plasma emission spectrometry, and X-ray fluorescence analysis are of primary importance in this field, as well as are eIectrochemica1 methods like pol arography and vol tammetry.
TL;DR: In this article, the relationship between staphylococcal lipid composition and resistance to parabens was investigated, and it was suggested that the resistance of Staphyloccus aureus to parabaens was related to membrane lipid composition.
TL;DR: Good agreement for the concentration of PAHs in the air particulate and diesel particulate extracts with published data using gas chromatography-mass spectrometry and high-performance liquid chromatography was found.
TL;DR: Analytical methods for eight tetracyclines (TCs) were established using silica gel high-performance thin-layer chromatography, reversed-phase thin- layer chromatography (RP-TLC) and high- performance liquid chromatography(HPLC), and good separations of eight TCs were obtained.
TL;DR: Secondary-ion mass spectrometry (SIMS) is used to sputter ions directly from thin-layr chromatograms in which components in a mixture have been separated.