Trennung der Triglyceride von Kuhmilch und Humanmilch durch HPLC und Untersuchung der Fraktionen durch GC

HPLC Separation of Triglycerides in Bovine and Human Milk and GLC Analysis of the Isolated Fractions Reversed-phase HPLC using acetonitrile-propionitrile mixtures and a very simple temperature programming device (temperature rising from 10–15°C up to 60°C) yielded optimum separation of the triglycerides in bovine milk (winter and summer) and mature human milk. The components in the isolated fractions were analysed by GLC for triglycerides and fatty acid methyl esters.     

Trennung von Triglyceriden nach Kettenlänge und Sättigungsgrad durch HPLC

Separation of Triglycerides According to Chain Length and Degree of Saturation by HPLC In routine fat analysis HPLC is efficiently used. For constant work columns with chemically bound C₁₈-groups are especially suitable. There are critical pairs of fatty acid-methylesters which however can be separated by means of elution agents basing on acetonitril. Oleic acid and elaidic acid can be separated by this way, too. By GLC triglycerides can only be separated according to the number ob C-atoms, whereas in HPLC double bounds have a great influence on the retention time, too. This is especially evident if elution agents, basing on nitrils, are used. The separation principle was determined by capillar gas chromatographic analysis of the HPLC fractions. Further on hints are given to avoid technical difficulties in the use of differential refractometers.     

Dünnschicht- und Gaschromatographie von Tocopherolen

Thin-Layer end Gas Chromatography of Tocopherols Oilseeds, to which an internal standard of tocopherol was given, were extracted for tocopherols with ethanol under conditions inhibiting oxidation using an Ultra-Turrax homogenizer. After filtration the ethanolic extract is briefly saponified and the unsaponifiable matter containing the tocopherols extracted into n-hexane. Then the hexane-fraction is washed alkalifree with water, dried over Na₂SO₄, concentrated and applied on a silicagel GF₂₅₄-plate, which is developed with dichloromethane. With co-chromatographed reference-tocopherols on the margins of the TLC-plate the presence of tocopherolquinones can be checked in UV-light, whereas the bands of tocopherols and tocotrienols are located by spraying the margins with Emmerie and Engel-reagent. The corresponding zones were scrapped off the plate, the silicagel extracted with 15 × 1 ml ethanol, the ethanol evaporated to dryness and the residue derivatised to trimethylsilylethers. Gaschromatography on 3 m SE-52/XE-60 or 1.5 m SE-30 columns gave a good separation of tocopherols and tocotrienols. Simultaneous qualitative and quantitative determination of tocopherols by GLC combined with the possibility of automation makes this analytical procedure superior to TLC and colorimetry of tocopherols. About 500 tests with different oilseeds in the range between 50-800 mg lipid and 20-2000 μg of total tocopherol/sample gave a recovery of 60% at a coefficient of variation of approximately 6%.     

Zur Analytik von Tocopherolen – Ein Methodenvergleich zwischen HPLC und GC

Analysis of Tocopherols by HPLC and GLC – A Method Comparison Study HPLC with straight phase columns as well as capillary GLC are suitable methods for the quantitative analysis of vitamin E isomers. In contrast to HPLC, it is necessary to saponify the oil for subsequent determination of tocopherols by means of GLC. Tocopherols are extracted quantitatively from the alkaline soap solution using cyclohexane. In order to test the accuracy of the GLC method, a BCR reference material was also included in the study and satisfying results were obtained. The random error, expressed as the standard error of the Y-estimate calculated by the method of least squares. indicated that 95% of the samples assayed by the two methods will agree within ± 16.7 μg/g.     

Die polarographische Bestimmung von Tocopherolen und Tocopherylchinonen in Ölen und Fetten

Polarographic Determination of Tocopherols and Tocopherylquinones in Oils and Fats A method for the polarographic determination of α-, γ-, and δ-tocopherols and the corresponding tocopherylquinones in oils and fats was worked out. After saponification of the samples and extraction of unsaponifiable matter with ether, the tocopherylquinones originally present in oils and fats are directly determined polarographically. Tocopherols present in the sample are oxidized quantitatively with cerium(IV) sulfate to the corresponding tocopherylquinones and latter are then likewise polarographed. The presence of substances accompanying tocopherols in the unsaponifiable matter does not interfere with the determination of tocopherols or tocopherylquinones. The tocopherol contents of different oils and fats are given.     

Trennung und Identifizierung optischer Aufheller durch ein- und zweidimensionale Dünnschicht-Chromatographie

Separation and Identification of Optical Brighteners by One and Two-Dimensional Thin-layer Chromatography Technical optical brighteners are separated into ionic and non-ionic groups on various layers of adsorbents and their mixtures resolved using polar mobile phases of basic nature, the non-ionic fluorescent agents are separated by one- and two-dimensional procedure. Besides a few exceptions, the technical brighteners invariably show more than one spots. Although from the number of these spots no conclusion can be drawn regarding the number of components present in the orginal fluorescent substance, however, exact identification of these brighteners is possible with the help of the Rf-values obtained. The solubility of technical brighteners in various solvents and solvent mixtures has been studied.     

Chromatographische Untersuchungen der hydrophoben Eigenschaften von Tocopherolen

Chromatographic Investigation of Hydrophobicity of Tocopherols We applied TLC and HPLC in purpose to compare hydrophobicity of α-,-β-,-γ- and δ-tocopherol. The obtained results were correlated with those of the quantum-mechanical calculations and with the respective steric effects. It was established that the investigated tocopherols can arranged in the below given order in respect of the sinking hydrophobic properties: α-tocopherol >β-tocopherol < γ-tocopherol < δ-tocopherol.     

Zur papier-chromatographischen Trennung und quantitativen Bestimmung von Methylketonen

Paper Chromatographic Separation and Quantitative Determination of Methyl Ketones A procedure is reported by which methyl ketones in natural fats are separated along with the unsaponifiables and paper chromatographically identified as their dinitrophenyl hydrazones followed by their elution from the paper chromatogram and quantitative determination by photometry with sufficient accuracy.     

Propylen/Propan‐Trennung im Festbettadsorber und durch Membranpermeation

The metal‐organic framework Mg₂(dhtp) with the linker dihydroxyterephthalate is known as MOF‐74 or CPO‐27. Mg₂(dhtp) has been synthesized as powder to measure breakthrough curves in a fixed‐bed adsorber and adsorption isotherms, and as a supported thin membrane layer for permeation studies. The measurement of the breakthrough curves of the binary propylene/propane mixture shows that separation with the fixed bed adsorber is possible. Propylene shows a higher affinity to Mg₂(dhtp). Although the single gas propane flux is slightly higher than the one of propylene, the binary propane/propylene mixture is not separated.