Separation of phospholipids in bovine tissue with disposable silica gel extraction columns

An improved SPE method for fractionation and identification of phospholipids

This work reports an efficient and universal SPE method developed for separation and identification of phospholipids derived from complex biological samples. For the separation step, sequential combination of silica gel-aminopropyl-silica gel SPE cartridges is applied. This setup enables separation of phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid, phosphatidylinositol, phosphatidylserine, cardiolipin, and sphingomyelin into four fractions according to the polarity of their headgroups. Sample acquisition of the SPE fractions is performed by a high-resolution LC-MS system consisting of a hybrid linear IT Fourier transform ion cyclotron resonance mass spectrometer coupled to RP-HPLC. The unequivocal advantage of our SPE sample preparation setup is avoidance of analyte peak overlapping in the determination step done by RP-HPLC. Overlapping phospholipid signals would otherwise exert adverse ion suppression effects. An additional benefit of this method is the elimination of polar and nonpolar (e.g. neutral lipids) contaminants from the phospholipid fractions, which highly reduces contamination of the LC-MS system. The method was validated with fermentation samples of organic waste, where 78 distinct phospholipid and sphingomyelin species belonging to six lipid classes were successfully identified.

Update on solid-phase extraction for the analysis of lipid classes and related compounds

This article provides information on the different procedures and methodologies developed when solid-phase extraction (SPE) is used for lipid component separation. The analytical systematics, established by different authors and designed to separate groups of compounds and also specific components by using a combination of chromatographic supports and solvents are presented. The review has been divided into three parts, which we consider well defined: edible fats and oils, fatty foods and biological samples. Separations of non-polar and polar lipids is the most extensive systematic, although many other published methods have been established to isolate specific components or a reduced number of components from edible fats and oils, fatty foods or biological samples susceptible to further analysis by other quantitative techniques.

Dependence of the 12-methyltridecanal concentration in beef on the age of the animal

The content of 12-methyltridecanal (12-MT), which contributes greatly to the characteristic aroma of stewed beef, was determined by a stable isotope dilution assay in meat samples from nine bovine animals of different ages. The results, which were related to the amount of phospholipids (PL), indicate that 12-MT content increases with the age of beef, e.g., from 36 micrograms.g(-1) PL in a 4-month-old calf to 810 micrograms.g(-1) PL in an 8-year-old cow. The increase of 12-MT content in PL per month varied between 8.4 and 10.9 micrograms.g(-1) PL (mean: 9.3 +/- 0.78 micrograms.g(-1) PL). Possibly 12-MT content is suitable as an indicator for the estimation of the age of a beef sample.