Vitamin D‐Bestimmung in Lebertran

Homberg, Elfriede

doi:10.1002/lipi.19930950606

Cited by 2 publications

(2 citation statements)

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“…This step is therefore not simply a columnchromatography step, but rather a kind of solid phase extraction. Aluminium oxide columns have been successfully applied in other analytical protocols to remove fatty acid soaps, e. g. in the sample preparation for the analysis of vitamin D in margarines [8] and of vitamin D in fish liver oils (cod liver oil) [9].…”

Section: Preparation and Isolation Of The Unsaponifiable Matter -The mentioning

confidence: 99%

Analysis of sterol content and composition in fats and oils by capillary-gas liquid chromatography using an internal standard. Comments on the German sterol method

Aitzetmüller¹,

Brühl

Fiebig

1998

Fett/Lipid

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The German method for the determination of sterols in oils and fats, which was originally developed by Homberg with the cooperation of Bielefeld [1][2][3], has been used with very good results for many years in Germany. On the other hand the German text sometimes led to misunderstandings because no authentic English translation, and no further explanations were available regarding the rationale (the pros and cons) of the various steps used in the analytical procedure. The fact, that such misunderstandings had occurred also surfaced in discussions around international standardization efforts, for example in ISO. There are at least two remarks in footnotes [in the Italian NGD method [4] and in the European method [5] for sterols in olive oils], that also point to possible misunderstandings of the reasons for the use of an alumina column in the German method.Following these discussions, an authentic English language version of the German sterol method was now prepared. At the same time, the method was reformulated and a number of minor variations, which had been tested in the laboratory, were included in the present protocol. For example, the internal standard is now added one step earlier.The present method is also faster than the older one, because by the full use of the advantages of an internal standard procedure, a number of steps, which aimed at a more quantitative recovery of the sterol fraction, could be omitted. As a result of this work, we now present a reformulated English version of the German method for sterol determination in fats and oils. In this English text, which is reproduced below (see below under "3 Description of the Method"), a number of additional explanatory comments were added. A full chapter has been added describing the pros and cons of the various steps and the major differences between this method and some other established methods. This chapter precedes the actual method protocol.The authors believe that the method described here is more widely applicable than other methods using other internal standards such as cholestanol, sitostanol or cholestane. In particular, the method is also applicable to cereal lipids, to animal fats, and to fat mixtures containing partially hydrogenated animal fats, where sitostanol and/or cholestanol may naturally occur [6]. In these cases, methods using cholestanol or sitostanol as internal standards require a second determination -without cholestanol or sitostanol -to obtain reliable quantitative results. This second determination can be avoided when betulin is used in the way as described here. Major Differences between the German Sterol Method and some other MethodsAdmittedly, the German sterol method requires some training and perhaps more detailed information before a newcomer can obtain useful results. There are a few very important points, plus a number of minor points, where the German sterol determination method ([3], and also the improved German language protocol) differs from some of the other methods of sterol determination. The advantages and...

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Section: Preparation and Isolation Of The Unsaponifiable Matter -The mentioning

confidence: 99%

Analysis of sterol content and composition in fats and oils by capillary-gas liquid chromatography using an internal standard. Comments on the German sterol method

Aitzetmüller¹,

Brühl

Fiebig

1998

Fett/Lipid

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“…In the former case, the selected fraction is collected, the mobile phase is removed, and the fraction is transferred to the gas chromatograph using some of the already known techniques [ 1 ]. When on-line coupling techniques are used, a more or less complex interphase is required [ 18 , 19 ] in order to allow the transition from the liquid state (high pressure) to the gas state (low pressure); moreover, interfaces are very different depending on whether the liquid chromatography is absorbent or distributive [ 20 , 21 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

SLE Single-Step Purification and HPLC Isolation Method for Sterols and Triterpenic Dialcohols Analysis from Olive Oil

León‐Camacho

Pérez‐Camino

2021

Foods

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The unsaponifiable fraction of oils and fats constitutes a very small fraction but it is an essential part of the healthy properties of some specific oils. It is a complex fraction formed by a large number of minor compounds and it is a source of information to characterize and authenticate the oil sample. Specially, the composition of sterols of any oil or fat is a distinctive feature of itself and, therefore, it has become a useful tool for detecting contaminants and adulterants in oils. A new supported liquid extraction (SLE) technique for the analysis and characterization of the unsaponifiable fraction of fats and oils is proposed. The SLE system includes, as a stationary phase, a combination of adsorbent materials which allow a highly purified unsaponifiable matter ready to be isolated by high performance liquid chromatography (HPLC) and quantified by gas chromatography (GC). This method ensures the removal of fatty acids, avoiding possible interferences and making the analysis of sterols and triterpenic dialcohols easier. The procedure uses a small sample size (0.2 g), reduces the volume of solvents and reagents, and reduces the handling of samples subjected to analytical control. All this is achieved without losing either precision—a relative standard deviation of each compound lower than the reference value (≤16.4%)—or recovery, being for all compounds higher than 88.00%. Therefore, this new technique represents a significant economic and time saving in business control laboratories, a larger productivity and enhancement of working safety.

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Vitamin D‐Bestimmung in Lebertran

Cited by 2 publications

References 6 publications

Analysis of sterol content and composition in fats and oils by capillary-gas liquid chromatography using an internal standard. Comments on the German sterol method

Analysis of sterol content and composition in fats and oils by capillary-gas liquid chromatography using an internal standard. Comments on the German sterol method

SLE Single-Step Purification and HPLC Isolation Method for Sterols and Triterpenic Dialcohols Analysis from Olive Oil

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