Sequential pressurized liquid extraction to determine brain-originating fatty acids in meat products as markers in bovine spongiform encephalopathy risk assessment studies

A new approach using sequential pressurized liquid extraction described recently [J. Poerschmann, R. Carlson, J. Chromatogr. A, 1127 (2006) 18-25] was applied to determine lipid markers originating from central nervous system (CNS) tissue of cows in heat-processed sausages. These studies are very important in quality control as well as risk assessment studies in the face of the bovine spongiform encephalopathy (BSE) crisis. Diagnostic CNS lipid markers, which should not be present in meat products without CNS addition, were recognized on complete transesterification as polar 2-hydroxy-fatty acids (2OH-24:0, 2OH-24:1, 2OH-22:0, 2OH-18:0, shorthand designation) as well as odd-numbered non-branched fatty acids beyond C(22). An array of other fatty acids including lignoceric acid (24:0), nervonic acid (24:1), arachidonic acid (20:4), and polyunsaturated nC(22)-surrogates are strongly related to CNS lipids, but occur as traces in meat products without CNS addition as well, thus reducing their value as diagnostic markers. Samples including meat products without CNS addition, meat with 3% CNS addition, as well as pure CNS homogenates, were subjected to sequential PLE (pressurized liquid extraction) consisting of two steps: n-hexane/acetone 9:1 (v/v) extraction at 50 degrees C to remove neutral lipids, followed by chloroform/methanol 1:4 (v/v) extraction at 110 degrees C to isolate polar CNS lipids (two 10 min PLE cycles each). To enhance the fractionation efficiency, cyanopropyl modified silica as well as chemically not modified silica sorbent was used at the outlet of the PLE cartridge to retard polar lipids in the first extraction step. This method proved superior to widely distributed exhaustive lipid extraction followed by solid-phase extraction (SPE) using silica regarding lipid recoveries and clear-cut boundaries between lipid classes. Methodological studies showed that the alcoholysis using trimethylchlorosilane/methanol (1:9, v/v) is an excellent method for the complete transesterification of lipids and quantitative formation of methyl esters.     

Quantification of fatty acids as methyl esters and phospholipids in cheese samples after separation of triacylglycerides and phospholipids

Determination of the individual fatty acid composition of neutral- and phospholipids as well as the phospholipid content of dairy food and other foodstuffs are important tasks in life sciences. For these purposes, a method was developed for the separation of lipids (standards of triolein and diacylphosphatidylcholines as well as three cheese samples) by solid-phase extraction using a self-packed column filled with partly deactivated silica. Non-halogenated solvents were used for the elution of the lipid classes. Cyclohexane/ethyl acetate (1:1, v/v) served for the elution of neutral lipids, while polar lipids were eluted with three solvents (ethyl acetate/methanol, methanol, and methanol/water) into one fraction. The separated lipid fractions were transesterified and the individual fatty acids were quantified by using gas chromatography coupled to electron ionization mass spectrometry (GC/EI-MS) in the selected ion monitoring (SIM) mode. The recovery rate for standard phosphatidylcholines was ∼90% and cross-contamination from neutral lipids was negligible. The method was applied to cheese samples. Quantitative amounts of individual fatty acids in the phospholipid fraction were <0.002-0.29% of total lipids from camembert, <0.002-0.12% of total lipids from mozzarella, and <0.002-0.18% of total lipids in a goat cream cheese. Differences in the fatty acid pattern of neutral and polar lipids were detected. The quantity of the fatty acids determined in the phospholipid fraction was divided by the factor 0.7 in order to convert the fatty acid content into the phospholipid content of the cheese samples. This factor is based on the contribution of 16:0 to dipalmitoylphosphatidylcholine (DPPC). The resulting DPPC equivalents (DPPC_eq) were found to be representative for the average contribution of fatty acids to all classes of phospholipids in dairy products. Using this approach, the phospholipid content of lipids from mozzarella, camembert, and goat cream cheese was 0.60%, 1.42% and 0.79%, respectively.     

Die Zusammensetzung der Neutrallipide aus normalen Hirnen alter Menschen

The chemical composition of lipids from six human brains (60–73 years) is reported. The total lipids out of cortex, white matter, diencephalon and cerebellum, pons, and medulla oblongata have been isolated and the neutral lipids have been separated in cerebrosides, sphingomyelines, and lecithins. The highest amount of pure lipids is found in the white matter, the lowest in the cortex. The relation of neutral lipids to acid lipids as well as the amount of cholesterol are about equal for all regions. The white matter shows more cerebrosides and sphingomyelines than the cortex, the opposite being the case for lecithins. The differences are strongly significant. The fatty acids out of the different pure lipid fractions have been analysed as esters by gas chromatography. Stearic and lignoceric acid, and cerebronic and hydroxy nervonic acid respectively are main components of cerebrosides, with only little differences for the different brain regions. The fatty acids of sphingomyelines consist mainly of stearic and nervonic acid; in the white matter these two acids are present about in the same quantity, whereas stearic acid dominates in the cortex and the other sections. Lecithins contain above all palmitic and oleic acid. The amount of the latter in the white matter is higher than that of palmitic acid.     

Lipid content and fatty acid composition in lemon wax

Lipids were extracted from lemon wax and fractionated into four classes on a silicic acid glass packed column by thin-layer chromatography (TLC). The free fatty acids, the fatty acid composition and the amount of each separated lipids were determined by capillary column gas chromatography (GC). Total lipids (TL) were 60 mg per 100 g raw weight and the ratio of nonpolar lipids (NPLs): glycolipids (GLs): phospholipids (PLs) was about 47:2:2. The main free fatty acids in lemon wax were hexadecanoic acid, cis-9-octadecenoic acid and cis,cis-9,12-octadecadienoic acid, while in the lipid fractions the main fatty acids were hexadecanoic acid in all the fractions, cis-cis-9,12-octadecadienoic and decanoic acids in triglyceride (TG) fraction, dodecanoic and cis-9-octadecenoic acids in diglyceride (DG) fraction and tetradecanoic, octadecanoic and cis-9-octadecenoic acids in GL and PL fractions. The ratio of unsaturated to saturated fatty acids showed a remarkable difference among these four lipid fractions. In PL and GL fractions this ratio was similar, 47.7% and 47.1% respectively, and in TG fraction it was 42.4% while in DG fraction this value was 23.5%.     

GC analysis of extractive compounds in beech wood

Various highly hydrophobic beech wood lipids were characterized and their quantities measured in hexane extracts by GC, using short and long capillary columns. More polar compounds were also identified in acetone extracts. Triglycerides, steryl esters, sterols, unsaturated fatty acids, as well as various monosaccharide units were determined as possible pollutants of papermaking systems.     

河豚鱼脂肪酸的气相色谱—质谱分析

采用ＧＣ／ＭＳ技术对２种河豚鱼（黄鳍、红鳍）脂肪提取物中的脂肪酸进行定性定量分析，共鉴别出２４种脂肪酸。多不饱和脂肪酸尤其是二十二碳六烯酸（ＤＨＡ）的含量很高，在黄猪中相对含量达３２．３２％，在红鳍中达２４．１１％。检出了在其它海产品中较少发现的１５－二十四烯酸（神经酸），是人体生长发育不可缺少的一种脂肪酸。对鱼肉脂肪提取方法及不同极性毛细管柱分离情况进行了讨论。     

Determination of sucrose esters of fatty acids in food additive premixes by gas chromatography and confirmation of identity by gas chromatography/mass spectrometry

A gas chromatographic (GC) method was developed for the determination of sucrose monoesters of fatty acids (mono-SuE) and sucrose acetate isobutyrate (SAIB) in food additive premixes. Mono-SuE and SAIB fractions were prepared by column chromatography with either a C8 or a silica gel solid-phase extraction column. The mono-SuE fraction was acetylated and applied to a wide-bore GC column (0.53 mm x 15 m) by splitless injection for determination. The SAIB fraction was applied to the GC column without derivatization. Gas chromatography/mass spectrometry was used to confirm the identity of GC peaks. The detection limits for mono-SuE and SAIB were 0.005 and 0.01%, respectively. Mono-SuE (C12, C14, C16, C18, and C18:1) and SAIB were found in commercial food additive premixes and some foods.     

Determination of chlorinated pesticides and PCB in pine needles — improved method for the monitoring of airborne organochlorine pollutants

A method to determine organochlorine pollutants in pine needles is described. Fresh, whole needles have been extracted for 48 h in dichloromethane to obtain the epicuticular wax fraction. The remainder has been cut into small pieces and again extracted with dichloromethane to obtain the internal lipids. Prior to gas chromatography, both the wax and the internal lipid extracts have been fractionated on two columns: first a silica gel/silica gel : sulphuric acid 2 : 1 column with dichloromethane as eluent and then a nitrophenyl silica column with hexane as eluent. Three fractions have been collected, fraction 1 containing hexachlorobenzene (HCB), fraction 2 containing polychlorinated biphenyls (PCB) and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene (DDE), and fraction 3 containing the remaining, more polar, organochlorine pesticides. For some pine species, the nitrophenyl silica column has been combined with a short aminopropyl silica column to obtain chromatograms of the PCB fraction free from negative peaks. The precision is in the range of 4–12% relative standard deviation, and the overall recovery is around 65–90%.     

Fast analysis by gas-liquid chromatography. Perspective on the resolution of complex fatty acid compositions

Separation of fatty acids as methyl ester (FAME) derivatives has been carried out using short and highly polar capillary column developed for fast gas-liquid chromatography (GLC) applications. The GLC parameters have been optimized in order to achieve separation of FAME ranging from 4:0 (butyric acid) to 24:1 in less than 5 min. Milk fat that has by far the most complex fatty acid composition among edible fats and oils has been used to optimize the method. The volume of the oven has been reduced in order to allow for a heating rate of 120 degrees C/min and to rapidly cool-down to the initial temperature (50 degrees C) of the GLC program. The GLC conditions developed are not suitable to achieve separation of positional and geometrical isomers of octadecenoic acid but are useful to perform separation of major fatty acids in milk fat. The conditions developed could be used to analyze edible fats and oils or biological samples such as plasma or red blood cell lipids. The results confirmed that short and highly polar fast columns operating under optimal conditions could be used to separate the fatty acids in various matrices.     

Overview of methods for the determination of trans fatty acids by gas chromatography, silver-ion thin-layer chromatography, silver-ion liquid chromatography, and gas chromatography/mass spectrometry

trans Isomers of naturally occurring cis-unsaturated fatty acids are produced when liquid vegetable oils or marine oils are partially hydrogenated to produce margarine, shortenings, and other hardened-fat products. Isomeric trans fatty acids are also formed in the intestinal tract of ruminants, and they appear in small amounts in dairy products and ruminant meat. Currently, satisfactory analyses for the fatty acid profiles of fats containing trans fatty acids are obtained by gas chromatography (GC) using capillary columns coated with highly polar cyanosilicone stationary phases. In capillary GC methods, the key limitation has been the incomplete separation of trans-monoenoic acid isomers from their cis isomers; however, recent reports have demonstrated that improvements in separation are attainable with the use of 100 m columns. In these columns, there is very little overlap of cis and trans isomers. More accurate trans fatty acid analyses can be obtained by coupling GC with either silver-nitrate thin-layer chromatography or silver-nitrate liquid chromatography.     

Lipid Biomarkers of Lens Aging

Lipids are important structural components of cell membranes and have profound effect on membrane fluidity. Lipid profiling and lipidomics have captured increased attention due to the well-recognized roles of lipids in numerous human diseases. Investigating lipid profiles not only provides insights into the specific roles of lipid molecular species in health and diseases, but can also help in identifying potential preventive or therapeutic biomarkers. Cataract, the loss of transparency of eye lens, is a disease of protein aggregation. There are several factors contributing to the stability in protein conformation. Age-related changes in lipid composition could be a contributing factor for altered protein–lipid interaction leading to protein aggregation and cataract. Keeping this in view, in the present study, fatty acid profiling from different age groups of lenses was carried out, using a freshwater catfish as the model. Total lipids were extracted from lenses of three different age groups of fishes (young, adult, and aged) and fatty acid methyl esters (FAME) were prepared and FAME analysis was carried out using gas chromatography–mass spectrometry. The results showed that three fatty acids viz. heneicosylic acid (C21), docosahexaenoic acid (C22:6), nervonic acid (C24:1) which were not present in the adult lens, appeared in the aged lens. On the other hand, eicosenoic acid (C20:1) present in the adult lens was found to be absent in the aged lens. The appearance or disappearance of these fatty acids can possibly serve as biomarkers of aging lens which is the most vulnerable stage for cataract development.     

Separation of acidic and neutral lipids by aminopropyl-bonded silica gel column chromatography.

The separation of acidic and neutral lipids by aminopropyl-bonded silica gel column chromatography is presented. Total lipid extracts from Escherichia coli and human spermatozoa were loaded onto pre-packed aminopropyl-bonded silica gel columns and the lipids separated into four fractions. Non-polar lipids including cholesterol esters, triglycerides, diglycerides, monoglycerides and cholesterol, were eluted with 4 ml of isopropanol-chloroform (1:2, v/v) (fraction 1); free fatty acids were eluted with 4 ml of 2% acetic acid in diethyl ether (fraction 2); neutral polar lipids, including phosphophatidylethanolamine, phosphatidylcholine, sphingomyelin and neutral glycolipids, were eluted with 4 ml of methanol (fraction 3); and, finally, polar acidic lipids, including phosphatidylglycerol, cardiolipin, phosphatidylinositol, phosphatidylserine, seminolipid lipid A and acidic glycosphingolipids, were eluted with 4 ml of chloroform-methanol-0.8 M sodium acetate (60:30:4.5, v/V/V) (fraction 4). The recoveries for the different lipids ranged between 89 and 98% and the intra-assay variation, expressed as the standard deviation, was less than 5%.     

Determination of cuticular and internal fatty acids of Chorthippus brunneus males and females using HPLC‐LLSD and GC–MS

Insects are of growing significance in veterinary medicine and human healthcare; therefore, an understanding of their biology is very important. The cuticular and internal fatty acid compositions of Chorthippus brunneus males and females have been studied for the first time. The lipids of males and females were separated into classes of compounds using high‐performance liquid chromatography with a laser light scattering detector. The free fatty acid (FFA) fractions obtained by HPLC were silylated and then analyzed by GC–MS. The cuticular lipids of males contained 15 saturated, four unsaturated with even‐numbered and two unsaturated with odd‐numbered carbon chains, FFAs ranging from C8 to C25. The major free fatty acids in males were C16 (20.8%), C18:2 (8.5%), C18:1 (32.9%) and C18 (24.4%). The cuticular lipids of females contained 17 saturated, four monounsaturated and two diunsaturated free fatty acids ranging from C8 to C30. The major cuticular fatty acids in females were C16 (25.1%), C18:2 (6.2%), C18:1 (23.7%) and C18:0 (33.2%). The internal FFAs of males consisted of 20 compounds ranging from C8 to C26. Four of these compounds were detected as major compounds: C16 (14.1%), C18:2 (21.6%), C18:1 (38.0%) and C18 (22.5%). Among 18 internal free fatty acids of females, C16 (22.3%), C18:2 (10.9%), C18:1 (40.2%) and C18 (20.5%) were the most abundant compounds. The following cuticular fatty acids present in the lipids of females were absent in the lipids of males: C26, C27 and C30. On the other hand, only C24 was absent from the cuticular lipids of females. Only C10 and C24 internal fatty acids present in the lipids of males were absent in the lipids of females. Copyright © 2016 John Wiley & Sons, Ltd.     

Identification of fatty acid methyl esters as minor components of fish oil by multidimensional GC-MSD: New furan fatty acids

The separation and analysis of furan fatty acids and other minor component fatty acids present at very low concentrations in complex sample matrices, such as fish oil or lipids derived from liver and testes, require several pre-analytical separation steps if single column gas chromatography is to furnish sufficient resolution: after extraction and transesterification hydrogenation, urea complex precipitation and argentation TLC have been applied prior to GC analysis of furan fatty acids. By using multidimensional GC-MSD with cooled injection and flow-controlled column switching with intermediate cold trapping, it has been possible to identify directly the methyl esters of furan fatty acids without further pre-analytical separation. The most common of the furan fatty acids can be subdivided into two groups depending on whether they bear a propyl or pentyl side group in the 5-position of the furan ring. In addition to the eight furan fatty acids known to be present in fish oil, six new ones were identified, four with propyl substitution and two with pentyl substitution. Four have earlier been reported to be present in the hepatopancreas of crayfish and in fish tissue, whereas the propyl-substituted 16,19-epoxy-17,18-dimethyldocosa-16,18-dienoic acid and the pentyl-substituted furan fatty acid 6,9-epoxy-7-methyltetradeca-6,8-dienoic acid were hitherto unknown.     

Comparison of Different Extraction Processes on the Physicochemical Properties,Nutritional Components and Antioxidant Ability of Xanthoceras sorbifolia Bunge Kernel Oil

In this study, we investigated and compared the oil yield, physicochemical properties, fatty acid composition, nutrient content, and antioxidant ability of Xanthoceras sorbifolia Bunge (X. sorbifolia) kernel oils obtained by cold-pressing (CP), hexane extraction (HE), aqueous enzymatic extraction (AEE), and supercritical fluid extraction (SFE). The results indicated that X. sorbifolia oil contained a high percentage of monounsaturated fatty acids (49.31–50.38%), especially oleic acid (30.73–30.98%) and nervonic acid (2.73–3.09%) and that the extraction methods had little effect on the composition and content of fatty acids. X. sorbifolia oil is an excellent source of nervonic acid. Additionally, the HE method resulted in the highest oil yield (98.04%), oxidation stability index (9.20 h), tocopherol content (530.15 mg/kg) and sterol content (2104.07 mg/kg). The DPPH scavenging activity rates of the oil produced by SFE was the highest. Considering the health and nutritional value of oils, HE is a promising method for X. sorbifolia oil processing. According to multiple linear regression analysis, the antioxidant capacity of the oil was negatively correlated with sterol and stearic acid content and positively correlated with linoleic acid, arachidic acid and polyunsaturated fatty acid content. This information is important for improving the nutritional value and industrial production of X. sorbifolia.     

Fatty acid profiles of sebaceous triglycerides by capillary gas chromatography with mass-selective detection

Fatty acid methyl esters prepared from the triglyceride fraction of skin surface lipids from six adult human males were chromatographed on a 50-m fused-silica column coated with the highly polar cyanopropylpolysiloxane phase. This permitted the resolution of double-bond positional and geometric isomers. By means of mass-selective detection, 33 saturated and 14 unsaturated fatty acid chain types were analysed. Interpretation of the mass spectra combined with precise calculation of equivalent chain length values permitted the identification of 22 saturated and all of the unsaturated chain types. Quantification by integration of total-ion and selected-ion chromatograms revealed marked variation in the triglyceride fatty acid composition between different subjects. The greatest variation was observed in the concentrations of even-carbon-numbered iso-branched acids, which ranged from 1.5 to 11% of the saturated and from 1.9 to 12.7% of the monounsaturated acids. The anteiso chain structures constituted 4-9% of the saturated and 3-6% of the unsaturated members. Fatty acids with 4-methyl branch showed the least variation, in the range 5.7-7.4%. Other methyl-branched acids made up 4-10% of the saturated group, but were not detected in the unsaturated acids fraction. Two 18:1 fatty acids were identified (a delta 8 and a delta 9), which possibly have different anatomical origins. Similarly, two 18:2 fatty acids (linoleic and a 2,3-dimethyl derivative) were identified. A 2-methyl C17 acid, probably of bacterial origin, was detected.     

Determination of lipids in infant formula powder by direct extraction methylation of lipids and fatty acid methyl esters (FAME) analysis by gas chromatography.

Fatty acid methyl esters (FAMEs) of pure triglyceride standards, oils, and fat from dry matrixes were formed by transesterification using sodium methoxide in methanol-hexane. FAMEs were produced by direct addition of sodium methoxide-hexane to samples and heating to simultaneously extract and transesterify acyl lipids. FAMEs were quantitated by capillary gas chromatography (GC) over a fatty acid concentration range of 0 to 1.7 mg/mL (r > or = 0.9997). Total fat was calculated as the sum of individual fatty acids expressed as triglyceride equivalents, in accordance with nutrition labeling guidelines. Saturated, polyunsaturated, and monounsaturated fats were calculated as sums of individual free fatty acids. Absolute recoveries determined from individual fatty acids in test samples ranged from 69.7 to 106%. Recoveries (relative to the C13:0 internal standard) for individual fatty acids in test samples ranged from 95 to 106%. Reproducibility was constant at each fatty acid level in the reaction mixture (n = 5, coefficient of variation [CV] < 2%). Absolute recovery determined from the sum of total fatty acids in standard reference material (SRM) 1846 (powdered infant formula) was 96.4%. Analysis of SRM 1846 gave results that agreed closely with the certified fat and fatty acid values. Analysis of commercial infant formula gave results that were comparable to those obtained with AOAC Method 996.01. The direct extraction methylation procedure is rapid, and the transesterification of acyl lipids to form FAMEs is complete within 15 min. Classical saponification and refluxing are not required. This method provides FAMEs free of interferences and easily quantitated by GC or confirmed by GC/mass spectrometry (MS). Unambiguous MS identification of individual FAMEs derived from pure standards, SRM 1846, and powdered infant formula product was obtained.     

Production of methyl ester fuel from microalgae

Microalgae are unique photosynthetic organisms that are known to accumulate storage lipids in large quantitites and thrive in saline waters. Before these storage lipids can be used, they must be extracted from the microalgae and converted into usable fuel. Transesterification of lipids produces fatty acid methyl esters that can be used as a diesel fuel substitute. Three solvents, 1-butanol, ethanol, and hexane/2-propanol, were evaluated for extraction efficiency of microalgal lipids. Type of catalyst, concentration of catalyst, time of reaction, temperature of reaction, and quality of lipid were examined as variables for transesterification. The most efficient solvent of the three for extraction was 1-butanol (90% efficiency), followed by hexane/2-propanol and ethanol. Optimal yield of fatty acid methyl esters was obtained using 0.6N hydrochloric acid in methanol for 0.1 h at 70°C.     

Comparison of solvent mixtures for pressurized solvent extraction of soil fatty acid biomarkers

The extraction and transesterification of soil lipids into fatty acid methyl esters (FAMEs) is a useful technique for studying soil microbial communities. The objective of this study was to find the best solvent mixture to extract soil lipids with a pressurized solvent extractor system. Four solvent mixtures were selected for testing: chloroform:methanol:phosphate buffer (1:2:0.8, v/v/v), chloroform:methanol (1:2, v/v), hexane:2-propanol (3:2, v/v) and acetone. Soils were from agricultural fields and had a wide range of clay, organic matter and microbial biomass contents. Total lipid fatty acid methyl esters (TL-FAMEs) were the extractable soil lipids identified and quantified with gas chromatography and flame ionization detection. Concentrations of TL-FAMEs ranged from 57.3 to 542.2 n mole g⁻¹ soil (dry weight basis). The highest concentrations of TL-FAMEs were extracted with chloroform:methanol:buffer or chloroform:methanol mixtures than with the hexane:2-propanol or acetone solvents. The concentrations of TL-FAMEs in chemical groups, including saturated, branched, mono- and poly-unsaturated and hydroxy fatty acids were assessed, and biological groups (soil bacteria, mycorrhizal fungi, saprophytic fungi and higher plants) was distinguished. The extraction efficiency for the chemical and biological groups followed the general trend of: chloroform:methanol:buffer ≥ chloroform:methanol > hexane:2-propanol = acetone. Discriminant analysis revealed differences in TL-FAME profiles based on the solvent mixture and the soil type. Although solvent mixtures containing chloroform and methanol were the most efficient for extracting lipids from the agricultural soils in this study, soil properties and the lipid groups to be studied should be considered when selecting a solvent mixture. According to our knowledge, this is the first report of soil lipid extraction with hexane:2-propanol or acetone in a pressurized solvent extraction system.     

Separation characteristics of fatty acid methyl esters using SLB-IL111, a new ionic liquid coated capillary gas chromatographic column

The ionic liquid SLB-IL111 column, available from Supelco Inc., is a novel fused capillary gas chromatography (GC) column capable of providing enhanced separations of fatty acid methyl esters (FAMEs) compared to the highly polar cyanopropyl siloxane columns currently recommended for the separation of cis- and trans isomers of fatty acids (FAs), and marketed as SP-2560 and CP-Sil 88. The SLB-IL111 column was operated isothermal at 168°C, with hydrogen as carrier gas at 1.0 mL/min, and the elution profile was characterized using authentic GC standards and synthetic mono-unsaturated fatty acids (MUFAs) and conjugated linoleic acid (CLA) isomers as test mixtures. The SLB-IL111 column provided an improved separation of cis- and trans-18:1 and cis/trans CLA isomers. This is the first direct GC separation of c9,t11- from t7,c9-CLA, and t15-18:1 from c9-18:1, both of which previously required complimentary techniques for their analysis using cyanopropyl siloxane columns. The SLB-IL111 column also provided partial resolution of t13/t14-18:1, c8- from c6/c7-18:1, and for several t,t-CLA isomer pairs. This column also provided elution profiles of the geometric and positional isomers of the 16:1, 20:1 and 18:3 FAMEs that were complementary to those obtained using the cyanopropyl siloxane columns. However, on the SLB-IL111 column the saturated FAs eluted between the cis- and trans MUFAs unlike cyanopropyl siloxane columns that gave a clear separation of most saturated FAs. These differences in elution pattern can be exploited to obtain a more complete analysis of complex lipid mixtures present in ruminant fats.