Die Dünnschicht‐Chromatographie auf dem Fettgebiet II: Trennung der Cholesterin‐Fettsäureester

Kaufmann, Christoph; Makus, Z.; Deicke, Apotheker F.

doi:10.1002/lipi.19610630304

Cited by 66 publications

(6 citation statements)

References 9 publications

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“…Thin layer chromatography (TLC) on silica plates in air using a 1 : 1 tetralin-hexane mobile phase produced only a single spot. (14) Thin layer chromatography under a nitrogen blanket produced two spots, one for the ester and a very small spot for the impurity, R, = 0.65. This material will be referred to in this text as the van Schuppen sample.…”

Section: Preparation Of Samplesmentioning

confidence: 99%

Polymorphism in Cholesteryl Esters: Cholesteryl Palmitate

Vogel

Barrall

Mignosa

1971

Molecular Crystals and Liquid Crystals

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The thermal transitions in cholesteryl palmitate have been evaluated and compared to previously reported data. A sample synthesized from carefully purified cholesterol and palmitic acid using p-toluene sulfonic acid compared directly with previously reported data. A sample of recrystallized ester from a commercial source showed a slightly depressed solid to mesophase transition temperature. However, the mesophase proved t o be smectic, commonly reported as monotropic with respect to the solid phase. Both smectic to cholesteric and cholesteric to isotropic liquid transitions were very sharp, indicating a very pure material. It is postulated that a specific impurity, an antioxidant, is responsible for this previously unreported effect. This effect of related compound interaction has been reported for nematic mesophase forming compounds. Thin layer chromatography, microscopy, depolarized light intensity analysis, differential scanning calorimetry and NMR spectroscopy data are discussed.

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Section: Preparation Of Samplesmentioning

confidence: 99%

Polymorphism in Cholesteryl Esters: Cholesteryl Palmitate

Vogel

Barrall

Mignosa

1971

Molecular Crystals and Liquid Crystals

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“…This produced a fine needle-like product with no odor of acid or oxidized cholesterol. Thin layer chromatography on silica plates using a 1: 1 tetralin-hexane mobile phase produced only a single spot [14]. This material is referred to in the text as the van Schuppen sample.…”

Section: • Preparation Of Samplesmentioning

confidence: 99%

Polymorphism in Cholesteryl Esters: Cholesteryl Palmitate

1971

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The thermal transitions in cholesteryl palmitate, an ester havingliquid-crystalline states, have been evaluatedand compared to previously reported data. A sample synthesized from carefully purified cholesterol and palmitic acid using p-toluene sulfonic acid compared directly with previously reported data. A sampleof recrystallized ester from a commercial source showeda slightlydepressed solid-to-mesophase transition temperature. However, the mesophase proved to be smectic, commonly reported as monotropic with respect to the solid phase. Both smectic-to-cholesteric and cholesteric-to-isotropic-liquid transitions were sharp, indicating a pure material.It is postulated that a specific impurity, possibly an isomeric cholesterol ester, is responsible for this previously unreported effect. This effect of related compound interaction has been reported for nematic-mesophase-forming compounds. Thin layer chromatography, microscopy, depolarized light intensity analysis, differential scanning calorimetry and NMR spectroscopy data are offered in support of this postulate.

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“…Smaller spots are obtained with cellulose powder than with kieselguhr or filter paper, due to its very fine structure. The carriers mentioned can be used equally well for reversed phase TLC, e. g., after impregnating with paraffin [96,125] or undecane [40][41][42]183]. The carriers mentioned can be used equally well for reversed phase TLC, e. g., after impregnating with paraffin [96,125] or undecane [40][41][42]183].…”

Section: Adsorbentsmentioning

confidence: 99%

“…[129] for analogy to PC). WOLFMAN and SACHS [183] have separated free cholesterol and desmosterol with the same system on silica gel G. Undecane has the advantage over paraffin, which can also be used with methyl ethyl ketone-acetonitrile (70 + 30) in the reversed phase technique [96], that it can easily be removed after the run and does not interfere in the detection of trace impurities using the usual reagents. The stationary phase was undecane on kieselguhr and the mobile phase, a mixture of acetic acid-acetonitrile (1 + 3), saturated with undecane.…”

Section: Sterolsmentioning

confidence: 99%

“…Here, too, partition chromatography in the undecane system [43] is more successful, as evident from partition system. Unsaturated fatty acid esters can be differentiated from the saturated esters only with difficulty in this way; success is more likely when an adsorption chromatographic separation is carried out in the first dimension and a partition chromatographic separation in the second [96]. Acetic acid is also a suitable mobile phase, as in PC [125].…”

Section: Sterolsmentioning

confidence: 99%

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