Lipid chromatographic method

After the extrachon of total lipids from four different genotypes of flax seed (Linum usitassimum) differing markedly in their acyl composihon, PTLC was used for the isolahon of different lipid classes in the neutral lipid frachon [69]. Application of planar chromatographic methods, including PTLC, in the separahon of food lipids has been reviewed with 40 references by Olsson [70]. The polar lipid fraction of niger seed (Guizotia abyssinica Cass.) collected from different regions of Ethiopia could be separated by PTLC on silica gel [71]. 

The same considerations will apply to other nonspecific methods of detection, such as fluorescence or UV absorbance determinations. Particularly with these methods, it must be appreciated that many of the cells used to form mono-layers secrete a variety of products such as lipids and proteins into both the donor and receiver compartments. These substances can result in a variable background in solutions and may interfere with solute quantitation. Even if a chromatographic method is used with fluorescence or UV detection, these products can still interfere with the separation unless specifically accounted for. 

The results for bacterial whole-cell analysis described here establish the utility of MALDI-FTMS for mass spectral analysis of whole-cell bacteria and (potentially) more complex single-celled organisms. The use of MALDI-measured accurate mass values combined with mass defect plots is rapid, accurate, and simpler in sample preparation then conventional liquid chromatographic methods for bacterial lipid analysis. Intact cell MALDI-FTMS bacterial lipid characterization complements the use of proteomics profiling by mass spectrometry because it relies on accurate mass measurements of chemical species that are not subject to posttranslational modification or proteolytic degradation. 

Chromatographic methods are employed to analyze and classify brain lipids 38... 

Chromatographic methods are employed to analyze and classify brain lipids. The lipids from brain are generally extracted with a mixture of chloroform and methanol using variations of a method originally described by Folch et al. In most procedures, the tissue or homogenate is treated with 19 volumes of a 2 1 (v/v) mixture of... 

The low-molecular-weight water-soluble fraction of LCP flour was found by thin layer chromatographic methods to contain several flavonoid components. To establish the role of flavonoids in the production of yellow color in biscuits, these components were extracted from LCP and glandless cottonseed flours with 85Z aqueous isopropyl alcohol (which is a better solvent for flavonoids than water). Before removal of the flavonoids, the flours had been treated with petroleum ether to extract residual lipids that could interfere with flavonoid isolation. Extraction of the residual lipids did not significantly alter the color of biscuits prepared with the extracted flours (Figure 7). 

Separation of crude lipid extracts into individual lipid classes is difficult and time-consuming. In some cases a crude separation of lipids can be attained by selective solvent extraction. For more extensive purification of lipids, the researcher must turn to chromatography. Chromatographic methods can both resolve a complex lipid mixture into the various classes of lipids and separate the individual components of a single class of lipids. 

LJ Hatam, HJ Kayden. A high-performance liquid chromatographic method for the determination of tocopherol in plasma and cellular elements of the blood. J Lipid Res 20 639-645, 1979. 

Ashraf, J., Butterfield, D. A., Jamefelt, J., and Laine, R. A. (1980). Enhancement of the Yu and Ledeen gas—liquid chromatographic, method for sialic acid estimation Use of methane chemical ionisation mass fragmentography. J. Lipid Res. 21, 1137-1141. 

Oxygen free radicals are elaborated during ischemia and reperfusion and have been strongly implicated in the pathophysiology of ischemic brain injury (114). These reactions may lead to oxidative injury to cellular lipids, proteins, and nucleic acids. Evidence for free radical elaboration in ischemia is obtainable by means of a microdialysis method in which administered salicylate is converted, in the presence of hydroxyl radical, to dihydroxybenzoic acid (DHBA) species—stable adducts detectable by chromatographic methods. A study from our laboratory of... 

High Performance Liquid Chromatographic and Gas Chromatographic Methods for Lipid Analysis... 

NP-HPLC Normal-phase liquid chromatographic methods applying Diol-columns or common silica columns are well suited for the analysis of the total steryl ferulate content. They require very little sample preparation, as total lipid extracts can frequently be directly injected into the column without purification or fractionation. Run times for SFs are also relatively short, and a good separation from other lipid components can be obtained in less than 10 min in traditional HPLC systems. Depending on the column type and the sample, SFs elute as one or two peaks. Two peaks are obtained from the separation of SFs, which have ferulic acid both in cis- and trans- configuration (Nystrom et ah, 2008). The relative retention time (obtained with a silica column and hexane/ethyl acetate 97 3 as eluent) of the cis- form is about 0.5 smaller than that of steryl irans -ferulates (Akihisa et al., 2000). 

This previous review provides a comprehensive overview of the major chromatographic methods for the analysis of tocopherols and tocotrie-nols developed until about 2000. The current chapter is not a comprehensive overview, but instead is a summary of the major advances in the field that have occurred since 2000. Two other valuable resources that review methods for the analysis of tocopherols and tocotrienols are the websites AOCS Lipid Library (2011) and Cyberlipid (2011). 

Selection of using normal-phase HPLC as the chromatographic method of choice is usually related to the sample solubility in specific mobile phases. Since NP uses mainly nonpolar solvents, it is the method of choice for highly hydrophobic compounds (which may show very stronger interaction in re versed-phase HPLC), which are insoluble in polar or aqueous solvents. Figure 1-5 demonstrates the application of normal-phase HPLC for the separation of a mixture of different lipids. 

CNSL used in polymerisation with formaldehyde as for example in friction dusts may not require elaborate analysis. Nevertheless interest in the industrial chemical uses of phenolic lipids has led to a study of quantitative methods of analysis by a variety of chromatographic methods. For cashew phenols these were first based on GLC. Thus the (15 3), (15 2), (15 1) and (15 0) constituents of methyl anacardate, cardol and cardanol have been separated by GLC on PEGA columns (ref.206), the free phenols (anacardic acid as methyl anacardate) by GLC on SE30 (ref207) and the hydrogenated anf fully methylated phenols on Dexsil and PEGA columns (ref.208). A further number of stationary phases have been investigated... 

WooUen, B.H., W.J. Irvine, PW. Brown, and D.H. Jones A thin-layer chromatographic method for tobacco lipid analysis Tob. Sci. 16 (1972) 101-103. 

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