scholarly journals A method for separation of phosphatidylcholine, triacylglycerol, non-esterified fatty acids and cholesterol esters from plasma by solid-phase extraction

2000 ◽  
Vol 84 (5) ◽  
pp. 781-787 ◽  
Author(s):  
Graham C. Burdge ◽  
Paul Wright ◽  
Amanda E. Jones ◽  
Stephen A. Wootton
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Neutral Lipids ◽  
Methyl Esters ◽  
Lipid Classes ◽  
Phase Extraction ◽  
Rapid Separation ◽  
Esterified Fatty Acids

Efficient isolation of individual lipid classes is a critical step in the analysis of plasma and lipoprotein fatty acid compositions. Whilst good separations of total lipid extracts are possible by TLC, this method is time consuming and a major rate-limiting step when processing large numbers of specimens. A method for rapid separation of phosphatidylcholine (PC), non-esterified fatty acids (NEFA), cholesterol ester (CE) and triacylglycerol (TAG) from total plasma lipid extracts by solid-phase extraction (SPE) using aminopropyl silica columns has been developed and validated. Following initial separation of polar and neutral lipids, individual classes were isolated by application of solvents with increasing polarity. Recoveries for combined plasma extraction with chloroform–methanol and SPE were (%): PC 74·2 (SD 7·5), NEFA 73·6 (sd 8·3), CE 84·9 (sd 4·9), and TAG 86·8 (sd 4·9), which were significantly greater for TAG and NEFA than by TLC (P<0·001). Both GC–flame ionisation detector and GC-MS analysis of fatty acid methyl esters demonstrated that there was no cross-contamination between lipid classes. Measurements of repeatability of fatty acid composition for TAG, PC, CE and NEFA fractions showed similar CV for each fatty acid. The magnitude of the CV appeared to be related inversely to the fractional fatty acid concentration, and was greatest at concentrations of less than 1 g/100 g total fatty acids. There was no evidence of selective elution of individual fatty acid or CE species. In conclusion, this method represents an efficient, rapid alternative to TLC for isolation of these lipid classes from plasma.

scholarly journals Identification and Quantification of Fatty Acids in T. viridissima, C. biguttulus, and C. brunneus by GC-MS

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Alexander M. Wathne ◽  
Hanne Devle ◽  
Carl Fredrik Naess-Andresen ◽  
Dag Ekeberg
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Solid Phase Extraction ◽  
Free Fatty Acids ◽  
Dry Matter ◽  
Solid Phase ◽  
Neutral Lipids ◽  
Methyl Esters ◽  
Phase Extraction ◽  
Chorthippus Biguttulus

Fatty acid (FA) profiles of the species Tettigonia viridissima, Chorthippus biguttulus, and Chorthippus brunneus were determined and quantitated. Extracted lipids were derivatized into FA methyl esters (FAMEs) prior to analysis by GC-MS. A total of 37 different FAs were identified in T. viridissima, yielding a total FA content of 10.4 g/100 g of dry matter. The contents of saturated FAs, monounsaturated FAs, and polyunsaturated FAs were 31.1, 35.9, and 33.0%, respectively. Lipids from T. viridissima were also fractioned into neutral lipids, free fatty acids, and polar lipids by offline solid phase extraction. For C. brunneus and C. biguttulus, 33 FAs were identified, yielding a total FA content of 6.14 g/100 g of dry matter. SFAs, MUFAs, and PUFAs, respectively, constituted 32.7, 25.1, and 42.1% of the total FA content. The contents of MUFAs, PUFAs, n-3 FAs, and n-6 FAs of each species, and the n-6/n-3 ratio, were subsequently discussed.

A unified protocol for the high-throughput measurement of PLFA, NLFA, GLFA and sterols from soil

2020 ◽  
Author(s):  
Stefan Gorka ◽  
Alberto Canarini ◽  
Bruna Imai ◽  
Georg Teischinger ◽  
Sean Darcy ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Mycorrhizal Fungi ◽  
Fungal Biomass ◽  
Solid Phase ◽  
Neutral Lipids ◽  
Lipid Extraction ◽  
Internal Standard ◽  
Lipid Classes ◽  
Pure Cultures

&lt;p&gt;Phospholipid fatty acids (PLFA) are widely used as biomarkers for soil microbial biomass. In more recent years, neutral lipid fatty acids (NLFA) have additionally been used as storage biomarkers. Both lipid classes are usually separated via silica solid phase extraction (SPE) after extraction with a mixture of chloroform, methanol and citric acid buffer. However, in recent years several studies reported incomplete or inconsistent separation of lipid classes, depending on minor differences in the polarity of the eluents used during the SPE. Moreover, while PLFA profiles have been tested on microbial pure cultures, the taxonomic specificity of NLFA is only assumed to equal that of PLFA.&lt;/p&gt;&lt;p&gt;Complementary to fatty acid based biomarkers, many studies quantify ergosterol as a reliable indicator for fungal biomass because the fungal-specific PLFA 18:1&amp;#969;9 and 18:2&amp;#969;6,9 also occur in plants, which compromises their use for detecting fungal biomass in plant tissue (for example mycorrhizal fungi in plant roots). Measuring ergosterol requires an additional extraction method, but existing protocols include silylation for further gas chromatography analysis and are thus not compatible with determining &lt;sup&gt;13&lt;/sup&gt;C by IRMS.&lt;/p&gt;&lt;p&gt;Here, we aimed to quantify the recovery of polar and non-polar lipid classes as well as ergosterol following lipid extraction and silica SPE fractionation. We used pure standards of representative phospholipids, glycolipids and neutral lipids with unique fatty acid chain lengths for unambiguous identification of the lipid class after SPE. Lipid fractionation was tested on a 96-well SPE plate with different eluents. Subsequently, we applied the modified method to characterize lipid fractions in microbial pure cultures from bacteria (Proteobacteria, Firmicutes, Actinobacteria), and saprotrophic and ectomycorrhizal fungi (Ascomycota, Basidiomycota).&lt;/p&gt;&lt;p&gt;Separation of lipid classes was achieved by successively eluting NLFA and sterols with a mixture of chloroform and ethanol (v:v = 98:2), glycolipid fatty acids (GLFA) with acetone, and PLFA with a mixture of methanol, chloroform and water (v:v:v = 5:5:1). GLFA were partially recovered in the NLFA or PLFA fraction depending on the nature of the lipid, which should be considered when interpreting PLFA data. Ergosterol recovery was unaffected by subsequent mild alkaline methanolysis of the NLFA fraction in which it was collected, allowing further analysis of both lipid classes in the same mixture. The gas-chromatographic method may be extended to elute both NLFA and (non-silylated) sterols in one run, assuming that the concentration of ergosterol in soil samples is high enough. Therefore, the method can be optimized by using an internal standard added to the NLFA fraction and simultaneously quantify ergosterol. Finally, we show how different lipid classes and attached fatty acid chains distribute in pure cultures of soil micro-organisms.&lt;/p&gt;

scholarly journals Home-made silver ion solid-phase extraction system for the analysis of trans fatty acids: comparison with commercial Discovery Ag-Ion SPE

Chemija ◽  
2018 ◽  
Vol 29 (1) ◽  
Author(s):  
Vilius Poškus ◽  
Vida Vičkačkaitė ◽  
Julita Dargytė ◽  
Gintautas Brimas
Keyword(s):  
Fatty Acids ◽  
Solid Phase Extraction ◽  
Trans Fatty Acids ◽  
Fatty Acid Methyl Esters ◽  
Solid Phase ◽  
Methyl Esters ◽  
Human Adipose Tissue ◽  
Silver Ion ◽  
Phase Extraction ◽  
Acid Methyl

A home-made silica-based silver ion solid-phase extraction (Ag+-SPE) system for the fractionation and subsequent gas chromatographic analysis of trans fatty acids in human adipose tissue is developed and examined. Analytical characteristics of the home-made Ag+-SPE column were compared with those of the commercial Discovery Ag-Ion SPE column and it was demonstrated that the both columns can be applied for the fractionation of fatty acid methyl esters.

scholarly journals Fatty Acids Profiles of Stipe and Blade from the Norwegian Brown Macroalga Laminaria hyperborea, Using Off-Line SPE and GC-MS

2016 ◽  
Author(s):  
Lena Oksdøl Foseid ◽  
Hanne Devle ◽  
Yngve Stenstrøm ◽  
Carl Fredrik Naess-Andresen ◽  
Dag Ekeberg
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Neutral Lipids ◽  
Methyl Esters ◽  
Lipid Fraction ◽  
Environmental Benefits ◽  
Laminaria Hyperborea ◽  
Alpha Linolenic Acid ◽  
Lipid Fractions

A thorough analysis and comparison of the fatty acid profiles of stipe and blade from Laminaria hyperborea, a kelp species found in the northern Atlantic, is presented. Lipids were extracted and fractionated into neutral lipids, free fatty acids and polar lipids, then derivatized to fatty acid methyl esters prior to GC-MS analysis. A total of 42 fatty acids were identified and quantified, including the n-3 fatty acids &alpha;-linolenic acid, stearidonic acid and eicosapentaenoic acid. An n-6/n-3 ratio of 0.8:1 was found in blade and 3.5:1 in stipe, respectively. The ratios vary between the lipid fractions within stipe and blade, with the lowest ratio in the polar lipid fraction of blade. The fatty acid amounts are higher in blade than in stipe, and the highest amounts of n-3 fatty acids are found within the neutral lipid fractions. The amounts of polyunsaturated fatty acids are 3.4 times higher in blade than stipe. This study highlights the compositional differences between the lipid fractions of stipe and blade from L. hyperborea. The amount of polyunsaturated fatty acids, compared to saturated- and monounsaturated fatty acids, as well as the n-6/n-3-ratio, is known to influence human health. In the pharmaceutical, food, and feed industries this can be of importance for production and sale of different health products. Additionally, lipids are today among the unused by products of alginate production, exploiting this material for commercial interest should give both economical and environmental benefits.

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