Fatty acids, methyl esters chromatogram

The GC-MS chromatogram obtained with the same substance after acid methanolysis and silylation is presented in Figure 10.10. The major compounds are fatty acid methyl esters corresponding to a mixture of an animal fat (attested by the presence of E15 0 and E17 0 with ante and iso isomers) and castor oil (attested by the presence of methyl ricinoleate E18 1,120H) [32]. Diterpenoid or triterpenoid resin components are not observed. 

Typical thin-layer chromatogram of lipids. The solvent system, hexane-diethyl ether-acetic acid (90 10 1). (1) cholesterol, (2) fatty acid, (3) triacylglycerol, (4) fatty acid methyl ester, (5) cholesterol ester, (6) glycerophosphatide, (7) sphingolipid, (8) 1,3- or 1,2-diacylglycerol, (9) 1 - or 2-monoacylglycerol. The Rf for (5), cholesterol ester, is calculated as follows ... 

Representative chromatograms of fatty acid methyl esters, derived from the three species most frequently used in dietary supplements, are shown in Fig. 18. In the chromatograms, the number and types of fatty acid methyl esters appear to be the same. However, ratios of the... 

Figure 5. GC/FTD analysis of the phospholipid-derived fatty acid methyl esters from derivatization/SFE extraction of Bacillus suhtilis. The front chromatogram shows the second extraction of the same sample (I.S.=internal standard).

Figure 2.- Total Ion Chromatogram of the thermal degradative products obtained after pyrolysis of the FA isolated from a water-logged peatland, in the absence (Py) and in the presence of TMAH (Py/TMAH). For peak identifications refer to Table I. Contaminants are noted by ( ) and the peaks labeled Cn are fatty acids and C n are fatty acid methyl esters. Reproduced with permission from reference 9. Copyright 1994 Elsevier Science— Netherlands.

Characterization of Humic Acids, Similar compounds are also released from soil HA and Figure 3 shows the chromatograms of the compounds released after pyrolysis in the presence of TMAH for two selected HA (77). High proportions of long-chain fatty acid methyl esters, as well as phenolic derivatives and aromatic acid methyl esters, were released. The released compounds might represent structural components of the humic macromolecule, as also suggested by different authors... 

Pyrolysis in the presence of TMAH has also been applied to the structural characterization of HAs isolated from low-rank coals. Figure 6 shows the chromatogram of the compounds released after the TMAH/pyrolysis of the HA isolated from a humic coal from Konin (Poland). A large variety of components were released, the lignin-derived phenol derivatives and aliphatic acid methyl esters being the most prominent. A series of fatty acid methyl esters were identified in the range from Cio to C34, with maxima at C16 and Cig showing an even-over-odd... 

Fig. 2. Partial gas chromatogram of total cyclic fatty acid methyl esters derived from a-linolenic acid. A Cp-Wax 52CB (25 m x 0.25 mm i.d., 0.20 pm film thickness) capillary column was used. There was an initial temperature of 160°C for 5 min followed by a program at 0.5°C/min to 180°C. Peaks a-h were cyclopentenyl acids and i-p were cyclohexenyl acids. Source Ref. 22.

FIGURE 8.3 THM chromatogram of the baked alkyd enamel paint smear. i-BuOH = isobutanol, BuOH = butanol, MB = methyl benzoate, P3ME = pentaerythritol trimethyl ether, DMOP = dimethyl orthophthalate, M = triazines from melamine, C,2, C,4, C,g, and C j = respective fatty acid methyl esters. 

Fatty acid methyl esters have also been examined by gas chromatography/FT-IR (Mantz, 1977). The chromatogram and selected spectra are shown in Fig. 9.7. The differences in retention times and the similarity of the spectra indicate a homologous series. However, the change in aliphatic chain length is reflected by only minor differences in the spectra. The influence of the ester moiety is so strong in the infrared that these spectra are very similar. 

Figure 6 A typical gas-liquid chromatogram of total bovine milk FAME prepared by NaOCHsfmethanol (10 min at SO C) followed by HCI/methanol (10 min at 80°C), and separated on a 100 m fused silica capillary column (SP-2560) Supelco Inc., Bellefonte, PA). I, iso a, anteiso numbers 1-20 are arbitrary consecutive numbering of all peaks in the region between 18 0 and 18 2o6 using this column. (22 6/>3) is not present in these milk samples but the position at which it should emerge in the chromatogram is indicated. Insert the methyl eicosanoate (20 0) to methyl arachidonate (20 4/>6) region of the GLC of total bovine fatty acid methyl esters prepared by using conventional catalysts. Reproduced with permission from Kramer JKG, Fellner V, Dugan MER, Sauer FD, Mossoba MM, and Yurawecz MP (1997) Lipids 32 1219-1228.

Figure 1.2 High-performance thin-layer chromatogram of methyl esters of fatty acids, showing separation based on unsaturation. The plates were developed in the solvent system hexane/ diethyl ether, 92 8 vol./vol. a = a standard mixture of tetracosaenoic (24 1 vol./vol.) and docosahexaenoic (22 6 vol./vol.) fatty acid methyl esters b = sea scallop lipids c = dogfish liver d = menhaden e = redfish f=rapeseed g = cod liver. Reproduced with permission from Shantha, N. C. and Ackman, R. G., Silica gel thin-layer chromatographic method for concentration of longer-chain polyunsaturated fatty acids from food and marine lipids, Canadian Institute oj Food Science and Technology Journal, 24, 156-60, 1991.

Fig. 4.8. Partial GC chromatogram of the acid-catalyzed methylated product of the isolated phospha-tidylethanolamine (PE) fraction from total beef heart lipids by fl-C (upper graph).The fatty acid methyl esters (FAME) and dimethylacetals (DMA) of total methylated PE were separated by TLC (solvent 3, Table 4.1) and analyzed using the same GC conditions.The last GC chromatogram represents the cyclic...

Fig. 2 Chromatogram of a standard mixture of fatty acid methyl esters (FAMEs) eluted on a 30 m DB-Wax column.

Fig. 1.4. Reversed-phase separation of fatty acid methyl esters, including CLA. A Nucleosil C g column (250 x 10 jim i.d. 5 mm particles) was used with acetonitrile as mobile phase, and ultraviolet detection at 234 nm. Methyl esters (20 mg) in acetone were injected, with acetonitrile as mobile phase and a flow rate of 4 mL/min. The fraction corresponding to the C g dienes may also contain some 14 0, 16 1, and certain polyunsaturated fatty acids. (Chromatogram kindly supplied by J.-L. Sebedio and P. Juaneda.)...

F g- 4.13. Chromatograms of autoxidized fatty acid methyl esters (FAME) kept in glass vials, exposed to O2 and ambient light for 8 d for (A) methyl linoleate, (B) c9,f1l-18 2, and (C) tl0,cl2-18 2. Chromatogram A indicates labeled peaks for pentanal (C -al), hexanal (Cg-al), f2,f4-decadienal (C Q-dienal), methyl stearate (is), methyl 9-oxo-nonanoate (9-oxo-FAME) and methyl linoleate (c9,cl2-C g.2-FAME). Chromatogram B also has labeled heptanal (C -al), 2-heptenal (C7.-,-al), 2-nonenal (C. -al), methyl 9,12-epoxy-9,11-octadecadienoate (Fg 2)/ chromatogram C has additionally labeled methyl nonanoate (Cg-FAME), 2-octenal (Cg. -al), methyl 10-oxo-decanoate (10-oxo-FAME) and methyl 10,13-epoxy-10,12-octadecadienoate (F q 3). 

Fig. 145. Thin-layer chromatogram of the mercuric acetate adducts of the fatty acid methyl esters from the alga Chlorella pyrenoidosa (cf with Figs. 144 and 146)...

Figure 16. Predicled (A) and experimenlal (B) chromatograms for fatty acid methyl ester mixture with temperature-programmed analysis at 40°C/min...

Figure 1 Gas chromatogram of fatty acid methyl esters from yeast strains expressing a wild-type or a mutant fatty acid hydroxylase from L fendleri...

Figure 5.13. Separation (part chromatogram) of very-long-chain fatty acids (methyl esters) from the cholesterol ester fraction of brain lipids from patients with Zellweger syndrome [838]. A fused silica WCOT column (12 m x 0.22 mm) coated with a methylsilicone phase (BP-1 ) was temperature-programmed from 160 to 320 C, with helium at 1 mL min as the carrier gas. (Reproduced by kind permission of the authors and of the Biochemical Journai, and redrawn from the original paper).

In quantitative analysis one should be aware of the use of technical products, such as linear ph-thalates (some important plasticiser alcohols are mixtures of C9-C11 mixtures), branched chain ph-thalates (C6-C12 mixtures), chlorinated paraffin plasticisers (C10-C12, C12-C14, C14-C17, C18-C20 fractions) [4]. Other technical products, such as fatty acid methyl esters (FAME), which comprise methyl laurate (C12, saturated), palmitate (Cie, saturated), stearate (Cis, saturated), oleic (Cis l), linoleic (Cis 2), linolenic (Cis 3), and arachidic (C2o 0) components, are typically accounted for by taking the total area of the methyl esters in each GC chromatogram [5]. Also lubricating agents are generally composed of primary fatty amide mixtures, such as palmitamide/stearamide/oleamide (20-25/70-80/2-5), caprylamide/capramide/laura-mide/myristamide/palmitamide/stearamide/linolea-mide (7-10/6-8/40-60/15-20/8-10/1-3/1-3), or... 

FIGURE 22.10 Three chromatograms including different tri, di, and mono acylglycerides different fatty acid methyl esters and tricaprin as internal standard. 

Figure 2.210 irm-GC-MS chromatogram of a fatty acid methyl ester (FAME) sampie after on-line combustion at 940 °C. The rectangular peaks in the beginning and at the end of... 

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