Showing papers on "Thin-layer chromatography published in 1971"
TL;DR: In this article, the compositions of the acids, hydroxy acids, alcohols, and diols from each ester fraction have been determined by gas liquid chromatography, and the major hydroxy acid (70%) obtained on hydrolysis was 15-hydroxyhexadecanoic acid.
129 citations
TL;DR: The isolation and identification of cholesterol α-oxide, coprostanol, β-sitosterol, cholest-4-en-3-one and cholesta-4, 6-dien- 3-one from human serum are reported.
Abstract: The isolation and identification of cholesterol α-oxide, coprostanol, β-sitosterol, cholest-4-en-3-one and cholesta-4, 6-dien-3-one from human serum are reported. Compounds were isolated by thin layer chromatography and were identified by gas liquid chromatography and gas chromatography-mass spectrometry (GC-MS). Data for standard sterols are also reported. The possible origins of these minor components and the significance of their presence are discussed.
114 citations
TL;DR: Different methods used to determine the formation of malonic dialdehyde in irradiated DNA lead to the conclusion that this type of sugar damage does not contribute very much to the breakage of the DNA backbone.
Abstract: SummaryIrradiation of aqueous solutions of DNA causes liberation of free nucleobases and of compounds which behave chromatographically like nucleosides. These components can be separated from irradiated DNA by DEAE-Sephadex chromatography. Their amount increases linearly with dose, resulting in a G-value of 0·16 to 0·18. Further separation of the liberated products by ion-exchange chromatography on Dowex 50 × 4 and by thin-layer chromatography on cellulose plates shows that about 60 per cent of the liberated material consists of nucleosides, part of which carries a damaged sugar molecule. Different methods used to determine the formation of malonic dialdehyde in irradiated DNA lead to the conclusion that this type of sugar damage does not contribute very much to the breakage of the DNA backbone. Several mechanisms leading to single strand breaks in DNA are discussed.
104 citations
TL;DR: Ceramides with mono-, di-, and trihydroxy long-chain bases, and normal (saturated and unsaturated), branched-chain, and 2-hydroxy fatty acids have been analyzed by thin-layer chromatography.
94 citations
TL;DR: For the unambiguos identification of the DANS-amides, mass spectrometry has turned out to be the most powerful tool.
94 citations
TL;DR: The results indicate that SRS is a biologically active carboxylic acid with hydroxyl groups and one or more double bonds but probably of non-prostaglandin nature.
Abstract: Cat paws were perfused with a physiological salt solution containing compound 48/80. In addition to histamine, a principle producing a slow sustained contraction of the isolated guinea-pig ileum appeared in the effluent. This slow reacting substance (SRS) was purified by ethanol extraction, solvent partition, silicic acid and anion exchange chromatography. The overall recovery was 10–20 per cent, calculated from the non-histamine smooth muscle stimulating activity of the ethanolic extract. The purification calculated from the crude lipid extract was about 200-fold. The purified material was dialysable, thermostable at neutral pH and more labile in acid than in alkaline milieu. It behaved homogenously on thin layer chromatography in several systems. The most marked biological effects were contraction of the isolated guinea-pig ileum and the human bronchus, increases in the bronchial resistance in guinea-pigs in vivo, in the colouration (Evan's blue dye i.v.) of guinea-pig skin after intradermal injection and in the blood flow in the cat hindlimb after intraarterial injection. Treatment of the purified material with N, N'-carbo-di-p-tolylimide, phenyl isocyanate, iodine monobromide, potassium permanganate or acetic anhydride abolished or greatly reduced the biological activity. Incubation of SRS with 15-hydroxy prostaglandin dehydrogenase in the presence of NAD+ resulted in no loss of biological activity. Together the results indicate that SRS is a biologically active carboxylic acid with hydroxyl groups and one or more double bonds but probably of non-prostaglandin nature.
63 citations
TL;DR: The lipid components of four strains of Agricus bisporus (Lange) Sing, the cultivated mushroom, were analyzed as discussed by the authors, and a method for obtaining mycelium free of compost was developed.
Abstract: The lipid components of four strains ofAgricus bisporus (Lange) Sing., the cultivated mushroom, were analyzed. Both sporophore and mycelial samples were obtained from beds in normal production. A method for obtaining mycelium free of compost was developed. Neutral lipids were separated from polar lipids by silicic acid column chromatography. Each fraction was separated by thin layer chromatography. Fatty acid methyl esters were analyzed by gas liquid chromatography and mass spectrometry. Sporophore extracts contained free sterol, free fatty acid, triglycerides, phosphatidyl choline and phosphatidyl ethanolamine. High amounts of linoleic acid were found in both neutral and polar lipid fractions. Mycelial extracts contained free fatty acids, triglycerides, phosphatidylcholine and phosphatidyl ethanolamine. No free sterol could be detected. Linoleic acid was also present in large amounts.
61 citations
TL;DR: Data and the observation that the glucose phosphate is hydrolyzed more than twice as rapidly in 1 n HCl as α-d-glucose 1-phosphate indicates that the compound obtained from the intermediate is β-d.glucosyl residues to O side chains of Salmonella typhimurium lipopolysaccharide, which suggests that the lipid moiety of the glucose-lipid is a polyisoprenol phosphate.
51 citations
TL;DR: The PTH derivatives of all amino acids commonly encountered in proteins are readily separable by these methods and Colored and fluorescent spots facilitate the identification and co-ordination of the other spots.
49 citations
TL;DR: The fractionation of marine-oil triglycerides according to their degree of unsaturation was achieved on silica gel thin layers with 8% silver nitrate and the following was found in both oils.
41 citations
TL;DR: In this article, the photometrically meter-mined density density of each spot on the thin layer plate was found to be proportional to its sucrose content, and the Ester content was then obtained by multiplying sucrose found by the factor, mol. wt. ester/mol.
Abstract: Thin layer chromatography was adapted for direct quantitative estimation of sucrose esters of palmitic acid. Urea-phosphoric acid spray was used to detect the sucrose moiety of the various esters. The photometrically metermined density density of each spot on the thin layer plate was found to be proportional to its sucrose content. Ester content was then obtained by multiplying sucrose found by the factor, mol. wt. ester/mol. wt. sucrose. Ester mixtures were prepared by interesterifying sucrose with various proportions of methyl palmitate in dimethylformamide solution. Positional isomers were observed at each level of substitution but could not be adequately separated from each other for quantitative evaluation.
TL;DR: In this article, a four-directional development TLC procedure incorporating trimethyl borate was applied to resolve cholesteryl glucoside, ceramides, monogalactosyl diglyceride, 1- and 2-monopalmitin, palmitic acid, cholesterol, 1,2- and 1,3-dipalmitin.
TL;DR: The excretion of sulfatides in human urine was studied in this article, where 24-hr urine collections were filtered and the results showed that the urinary sulfatide composition was remarkably similar to that previously reported in the kidney, including differences in fatty acid pattern.
TL;DR: In this paper, a technique was developed for evaluating the flavor of freshly crushed onion using thin-layer chromatography with solvents containing large amounts of hydrochloric acid, which measured the relative concentration of the lacrimator and other products of the action of alliinase on the flavor precursor, S-propenyl-L-cysteine sulfoxide.
Abstract: SUMMARY A technique was developed for evaluating the flavor of freshly crushed onion. The method consisted of grinding the onion and extracting the juice with solvent. The solvent extract was reacted with cysteine to form an amino acid derivative of the flavor compound and finally the derivatives were separated by thin-layer chromatography with solvents containing large amounts of hydrochloric acid. The principal advantage of the method is that it can measure the relative concentration of the lacrimator and other products of the action of alliinase on the flavor precursor, S-propenyl-L-cysteine sulfoxide. Apparently, this is not measurable by the usual gas-liquid chromatography technique because of decomposition in the column.
TL;DR: In this article, a two-dimensional thin-layer chromatographic method was developed to separate p,p′-DDE and other DDT analogs from polychlorinated biphenyl compounds.
TL;DR: In this paper, thin-layer chromatography on silica gel is proposed as a method for assigning the relative configurations of diastereomeric pairs of compounds of the above type.
TL;DR: Application of the 5-androstenediol method to the measurement of plasma D-sulfate (DS) after solvolysis yields results in agreement with analysis by gas-liquid chromatography and Zimmermann reaction.
TL;DR: Analysis by gas-liquid chromatography—mass spectrometry of the trimethylsilyl ether derivatives revealed that about 20% of these compounds contained 2-hydroxy acids, and of interest was the finding that C20-sphingenine constituted about20% of the total long chain bases.
Abstract: Glucosyl ceramides were isolated from young mouse brains by a combination of column chromatography and thin layer chromatography. Analysis by gas-liquid chromatography—mass spectrometry of the trimethylsilyl ether derivatives revealed that about 20% of these compounds contained 2-hydroxy acids (mainly cerebronic acid, 2-hydroxy behenic acid, and 2-hydroxy stearic acid). The rest contained non-hydroxy acids (stearic acid was most abundant; arachidic acid, lignoceric acid and behenic acid came next). Unsaturated acids were virtually absent. The major long chain base was C18-sphingenine. Small amounts of C18-sphinganine were also present. Of interest was the finding that C20-sphingenine constituted about 20% of the total long chain bases.
TL;DR: The present data are consistent with an addition product whose bridging group is a new chroman ring and does not reduce Emmerie-Engel reagent prior to treatment with concentrated hydriodic acid, nor do the ether-extractable products after such treatment.
Abstract: There is evidence that an addition compound of oxidizeddl-alpha-tocopherol and linoleic acid is formed when the components are absorbed in mixed monolayer on silica gel at a molecular ratio of 1∶20, and subjected to heating in air at 80C. A relatively nonpolar tocopheryl quinone is also formed in smaller amounts. These are the major tocopherol oxidation products isolated in this system and do not correspond to any known to the authors. The addition compound has about the same mobility as linoleic acid in most thin layer chromatography (TLC) and chromatographic systems, but can be isolated by successive chromatography on silica and gel filtration on Sephadex LH-20. It yields a single spot in TLC in several systems. The elemental analysis is reproducible and consistent with a simple addition compound of linoleic acid and bivalently oxidized tocopherol. The compound has a carboxyl group which can be esterified. The ester has about the same TLC mobility as methyl linoleate. The molecular weight of the ester is 722.6. The UV spectrum shows a single peak, 2
max
ETOH
=3000 A, E=4.74. The IR spectrum shows a very strong chroman ether band at 9.12 μ, a strong methyl band at 7.24 μ and carboxyl but no hydroxyl absorption. The NMR spectrum shows, in contrast to that of tocopherol, a reduction in aromatic methyl protons, a carboxyl proteon exchangeable with deuterium oxide, but no hydroxy proton. The compound does not reduce Emmerie-Engel reagent prior to treatment with concentrated hydriodic acid, nor do the ether-extractable products after such treatment. The present data are consistent with an addition product whose bridging group is a new chroman ring.
TL;DR: Ceramides in human plasma have been isolated, identified and quantitated, using silicic acid chromatography, thin-layer Chromatography, argentation chromatography of the ceramide acetates, and gas-liquid chromatography—mass spectrometry of ceramide trimethylsilyl ethers.
Abstract: Ceramides in human plasma have been isolated, identified and quantitated, using silicic acid chromatography, thin-layer chromatography, argentation chromatography of the ceramide acetates, and gas-liquid chromatography—mass spectrometry of ceramide trimethylsilyl ethers. Synthetic ceramides were prepared and used as references. Only ceramides with normal fatty acids were detected. Sphingosine was the main long-chain base, but ceramides with hexadecasphingosine, heptadecasphingosine, sphingadienine, sphinganine, and nonadecasphingosine were also found. Ceramides with long chain fatty acids dominated. The total amount of ceramides was 5.64 ± 1.51 μg/ml among 27 apparently healthy subjects.
TL;DR: A mechanism of biosynthesis involving head to tail condensation of acetyl CoA with malonyl CoA is indicated, which increases the synthesis of 6-methylsalicylic acid and forms a considerable amount of the acid formed in the dark.
Abstract: 1
Chloroplasts isolated from dark grown barley leaves greened for 6 h rapidly incorporate [1-14C]acetate into 6-methylsalicylic acid. Etioplasts synthesize little 6-methylsalicylic acid and mature chloroplasts lack this activity.
2
Carbon dioxide and CoA are essential cofactors for the synthesis. While light increases the synthesis of 6-methylsalicylic acid, a considerable amount of the acid is formed in the dark. Externally supplied NADPH has no effect on the incorporation of [1-14C]acetate into 6-methylsalicylic acid by isolated chloroplasts.
3
The biosynthesized 6-methylsalicylic acid has been purified by thin layer chromatography. Characterization of the labeled compound is done by radio gas liquid chromatography, by repeated crystallization to constant specific radioactivity and by identification of its nitration product as 3-methyl-2,4,6-trinitrophenol.
4
Since 75% of the radioactivity of 6-methylsalicylic acid synthesized by isolated chloroplasts is confined to the aromatic nucleus, a mechanism of biosynthesis involving head to tail condensation of acetyl CoA with malonyl CoA is indicated.
TL;DR: An improved method for the assay of 17-Hydroxyprogesterone (17-hydroxy-4-pregnene-3,20-dione) in blood is presented using a Celite column which is more rapid and yields lower blanks than thin layer chromatography.
TL;DR: In this paper, thin-layer chromatography of carbohydrates on silica-gel layers impregnated with molybdic or phospho-tungstic acid has been investigated.