Chromatostrip analysis of fatty acid derivatives

Abstract

Chromatostrips provide a rapid and convenient method of examination of samples by spot tests and by ascending or descending chromatography. Ascending chromatography for the examination of mixtures is carried out on 12ȕ140‐mm. glass strips coated with 5% starch‐bonded silicic acid, while descending chromatography is done on 12ȕ200‐mm. strips. The 5% starch‐bonded silicic acid coatings are resistant to normal handling, may be marked with a soft lead pencil, and may be stored indefinitely for reference. Three detection systems are employed: fluorescent minerals for conjugated unsaturates, fluorescein‐bromine for unsaturates, and 2艂,7艂‐dichlorofluorescein for all types of compounds. Positive tests result in characteristic spots when observed under normal or ultraviolet illumination. This permits the classification of components, after separation on the chromatostrips, into the groupings of conjugated unsaturated, unsaturated (or easily brominated), and saturated compounds.

Gas chromatography‐mass spectrometry of methyl esters of unsaturated oxygenated fatty acids

“…Advantages from analysis of the silylated unsaturated oxygenated esters over analysis of their saturated analogs are: (a) unsaturation, in addition to the oxygen function, is located; (b) side reactions that occur during catalytic hydrogenation (7)(8)(9) and complicate GC analysis are avoided; (c) rearrangements during MS are minimized; and (d) molecular ions (M) are usually present in significant amounts.…”

New Enynolic Acids from Acanthosyris. Structures and Chemistry1

“…These components were separated by column chromatography on silica gel. The first fraction, 26 mg, had the following absorption maxima: infrared, 4.52 (C=C), 6.13 (C=C), 9.03 (OCH3), 10.95 (CH^CH-), and 10.48 µ (irans-enyne); ultraviolet, X"the""e 229 µ (ML 510).…”

“…The second fraction (11 mg) had the following spectral characteristics: infrared, 5.11 (aliene), 6.13 (C=C), 9.05 (OCH3), 10.95 (CH2=CH-), and 11.40 µ (aliene);27 ultraviolet, XcmM°ha,a°a 178 µ (ML 935).…”

“…111.5-112.5°, [a]n +24°(lit.23 Hd +23°). 3a-Nitro-5a-cholestane (10) from 3a-Amino-5a-cholestane (9).…”

New Techniques for the Evaluation of Organic Pollutants

“…15 ,16 In practice, the thin layer of material is spread on glass plates, activated, spotted with sample, placed in a saturated atmosphere of solvent, and treated with a solvent appropriate for either ascending or descending partition; further reversed-phase partition with a change in solvent is also possible. After partition, the location and identification of sample components may be made by reagent spray," and the sample component may be separated and measured quantitatively.Y The method is most rewarding if used in combination with gas-liquid chromatography, paper and column chromatography with radioactive tracers, and with derivative metbods.t": 18 Thin-layer chromatography is reportedly an easier method to handle than others of similar capability 19 ; complex structures (terpenes, lipids, phospholipids, sulfolipids, glycolipids, steroids, bile acids, vitamins, amines, amino acids, peptides, proteins, purines, carbohydrates, nucleosides, nucleotides, nucleic acids, barbiturates, alkaloids, insecticides, herbicides, pesticides, and many other compounds) may all be identified, often in minutes, whereas other chromatographic meth-ods may take hours or days. '6-2o Separations are much sharper than the fractionation obtained in paper or column chromatography.…”