Capillary Gas-liquid Chromatography Research Articles

Change of plasmalogen content of red blood cells in myocardial hypoxia and acidosis

Background: The contribution of hypoxic conditions to the chemical composition of membranes is not completely established. Plasmalogens, containing an alkenyl group with aldehydogenic ether linkage, are significant components of membrane lipids and their level can change in oxygen deficiency.Methods: Analysis of plasmalogens in red blood cells was performed in patients (n = 17) with coronary heart disease, stable angina (functional class II–III) and coronary atherosclerosis. The control group consisted of 17 healthy volunteers. In addition, isolated blood samples of seven healthy volunteers were analysed before and after 180 min incubation at 37 °C.Fatty acid ethyl esters and diethyl acetals of fatty aldehydes, obtained during sample preparation from red blood cells, were analysed by capillary gas–liquid chromatography. Quantitative assessment of the change of the plasmalogen levels was evaluated as change of the share of fatty aldehyde diethyl acetals in the total sum of fatty aldehyde diethyl acetals and fatty acid ethyl esters.Results: In comparison with the healthy volunteers, an increase in plasmalogen content of red blood cells and a reduction of the pH of the blood plasma in the group of patients with coronary heart disease were detected. In experimental hypoxia, there was an increase in the plasmalogen content of the red blood cells and a plasma pH decrease in all samples subjected to the incubation.Conclusions: The results indicate changes in the physicochemical properties of the cell membrane in hypoxia. One of the most likely reasons of the increase of plasmalogen content in the membranes may be a more significant increase in activity of calcium-dependent phospholipases in comparison with the activity of calcium-independent plasmalogen phospholipases.

New approach shows no association between maternal milk fatty acid composition and childhood wheeze or asthma.

Previous observational studies have implied breastmilk fatty acid composition may play a role in the development of atopic eczema or atopic sensitization in breastfed infants and toddlers. However, studies investigating associations with wheeze and asthma in later childhood are scarce and did not account for inherent correlation of compositional data. Our aim was to explore the association of maternal milk fatty acid composition with childhood wheezing phenotypes and asthma up to age 13years using a new statistical approach. Breastmilk was collected 6weeks and 6months postdelivery in the Ulm Birth Cohort Study (n=720 and n=454, respectively). Concentrations of 28 fatty acids were measured by high-resolution capillary gas-liquid chromatography. To control for constant-sum constraint, concentration data were transformed using the centered log ratio method. Compositional biplots and correlation matrices were used to group centered log ratio transformed fatty acids. Adjusted risk ratios with parent-reported wheezing phenotypes and doctor-diagnosed asthma were computed using a modified Poisson regression. We observed no straightforward evidence of associations between overall breastmilk fatty acid composition and specific wheeze phenotypes or doctor-diagnosed asthma. Using appropriate statistical methodology, we report null associations. These findings may partly be attributable to several cohort-specific factors associated with breastfeeding and breastmilk collection. Further studies could improve on ours by analyzing samples of breastmilk and formula and by including all children for whom these are exclusively or together the major source of fatty acids in the first months of life.

Trends in the analytical quality control of the potable ethanol

Current paper is a brief analysis of the normative documents, patents, original articles, reviews and monographs devoted to the problem of the quality control and safety of the rectified ethanol, distillates, and water-alcohol solutions. The two fundamentally different trends in the development of methods for the analytical control of impurities in the ethanol are singled out. First is improving the control of impurity components using various hybrid methods by searching for and identifying components-markers of quality products and falsified products. The other trend is the definition of integral indicators of the authenticity and quality of the products using optical, spectral or sensory methods. Traditional methods and modern developments for the qualitative and quantitative analysis of impurities in drinking ethanol using chromatographic, optical, spectral and sensory methods of the chemical analysis are discussed. It is noted that the method of capillary gas-liquid chromatography with flame ionization detection was the most widely used for the identification of ethanol samples, and for determination of the nature and content of microimpurities. Capillary gas-liquid chromatography with the tandem mass spectrometric detection is recognized as an effective method, promising for the introduction into the analytical practice for the quality control and safety of the food ethanol. Chromatographic methods have made it possible to reliably characterize the main microimpurities of the ethanol of various genesis. To monitor the technology of bugorectification, bottling and storage, and for the recognition of counterfeit and defective products and falsification it is also possible to successfully use gas chromatography in conjunction with olfactometry, head space analysis, pyrolysis chromatography, high-performance liquid chromatography, ion chromatography and capillary electrophoresis. High efficiency in the identification of alcohol of various origins in vodka is noted for the method of spectral-luminescent analysis. The prospects of using electronic multisensory systems to control the type and intensity of the smell and taste using the sets of chemical sensors are shown for the control of alcohol production. Keywords : ethyl alcohol from food raw materials, identification of trace contaminants, sensory analysis, chromatography, optical and spectral methods, chemical sensing, integral quality indicators DOI: http://dx.doi.org/10.15826/analitika.2017.21.3.010 O.B. Rudakov 1 , S.Y. Nikitina 2 1 Voronezh state technical University, ul. 20-letiia Oktiabria 84, Voronezh, 394006, Russian Federation 2 Voronezh State University of Engineering Technologies, prospekt Revolyutsii 19, Voronezh, 394036, Russian Federation

The study of fatty-acid spectrum of blood serum in patients with aspirin associated polypous rhinosinusitis

Aim of research – to study the composition of the main representatives of polyunsaturated and saturated fatty acids in blood serum of patients with chronic polypous rhinosinusitis, associated with intolerance to acetylsalicinic acid.Materials and methods. The fatty-acid composition of blood serum was determined by the method of capillary gas-liquid chromatography in 20 ill and 7 healthy donors.Results: The change of composition of unsaturated fatty acids is in increase of arachidonic acid level, decrease of the content of its main predecessors – linoleic and eicosapentaenoic acids, normal level of intermediate products:α – and γ – linoleic acid and increase of the level of oleic acid. The content of the main saturated fatty acids: palmitic, stearic, arachidic ones is increased. The fatty acids imbalance testifies to the proinflammatory directionality of lipid metabolism.Conclusions:1. The increase of the level of polyunsaturated (arachdonic and oleic acids) leads to the compensatory decrease of the level of the main predecessors of arachinonic – linoleic and eicosapentaenoic acids. This mechanism allows keep the intermediate products of synthesis of arachidonic acid - α – and γ – linoleic acids at the normal level.2. The content of saturated fatty acids with alternative biological effects is increased in blood serum as a compensatory mechanism of leveling of biological effects of polyunsaturated fatty acids and their metabolites,.3. The revealed imbalance of fatty acids testifies to the proinflammatory directionality of the lipid metabolism.4. The changes of fatty-acid spectrum of lipids in the blood serum prove the hypothesis of “genetic block COG1” as the main pathogenetic link of aspirin associated polypous rhinosinusitis

Low n-3 long-chain polyunsaturated fatty acids in newly diagnosed celiac disease in children with preexisting type 1 diabetes mellitus.

Fat malabsorption can occur in celiac disease (CD) owing to villus atrophy and inflammation of small intestinal mucosa. Abnormal fatty acid (FA) status of intestinal mucosa in children with CD was reported earlier. Previously we found significantly reduced availability of n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFA) in children and young adults with type 1 diabetes mellitus (DM). The aim of this study was to investigate FAs in plasma lipid classes in children with newly diagnosed CD with or without preexisting DM. FA composition of plasma samples of children with untreated CD only (n = 20) and with preexisting DM (CDDM, n = 8) were compared with those of healthy controls (n = 21). Detailed analysis of phospholipid, triacylglycerol, and sterol ester FAs was performed by high-resolution capillary gas-liquid chromatography. Significantly decreased docosapentaenoic (C22:5n-3), docosahexaenoic (C22:6n-3), n-3 polyunsaturated fatty acids (n-3 PUFA), and n-3 LCPUFA values were found in CDDM group compared with controls and patients with CD. When compared with healthy controls, no significant difference was found in plasma FAs of children with newly diagnosed CD only. Children with CDDM showed marked signs of reduced availability of n-3 PUFA and n-3 LCPUFA in circulating lipids. Although different tissues express membrane FAs differently, our present study suggests that CD on its own does not necessarily lead to detectable disturbances of essential FA metabolism in plasma and supports the concept that DM has significant impact on plasma FA composition in children.

Evaluation of Fatty Acid Composition, Tocols Profile, and Oxidative Stability of Some Fully Refined Edible Oils

Present study includes evaluation of fatty acid composition, tocols profile, and oxidative stability of some fully refined edible oils. Fully refined sunflower, soybean, corn, hazelnut, peanut, and canola oils were analyzed for fatty acids by capillary gas liquid chromatography, tocols by normal phase-high performance liquid chromatography and oxidative stability by rancimat. Free fatty acid, peroxide value, and iodine value of investigated oils were determined by titrimetric methods. Saturated, mono-, and polyunsaturated fatty acids were found to be in the ranges between 2.03–18.58, 23.39–77.26, and 14.39–58.52%, respectively. Tocols and oxidative stability of the investigated oils were found to be in the ranges between 488.88–913.51 mg kg−1 and 3.05–4.99 h, respectively.

Fatty Acid Composition of Erythrocytes and Blood Plasma in Multiple Organ Dysfunction Syndrome

This paper focused on analysis of fatty acids of erythrocytes and blood plasma in patients with multiple organ dysfunction syndrome. For the study, fatty acids ethyl esters, obtained during sample preparation from blood plasma and erythrocytes, were analyzed by capillary gas-liquid chromatography. Statistical analysis was performed using the Mann-Whitney U test (p<0.05). The conducted research has shown that blood plasma of MODS patients has a decreased relative level of polyunsaturated fatty acids and saturated stearic (C18:0) acid, while there is a significant increase in relative content of monounsaturated fatty acids. In conditions of an increased level of monounsaturated palmitoleic (C16:1) and oleic (C18:1) fatty acids in blood plasma, only the level of palmitoleic (C16:1) acid is increased in erythrocytes. The disorder of lipid composition constancy of erythrocyte membranes is also manifested by a change in the content of saturated palmitic (C16:0) and polyunsaturated linoleic (C18:2) fatty acids. The changes revealed in fatty acid composition of erythrocytes may indicate systemic modifications of cell membranes in multiple organ dysfunction syndrome. The changes in blood plasma fatty acid composition in patients with multiple organ dysfunction syndrome is mainly caused by activation of lipolysis in fat depots.

Distribution features of biomarker hydrocarbons in Asphaltene thermolysis products of different fractional compositions (using as an example oils from carbonate deposits of Tatarstan oilfields)

Asphaltenes of two types, A1 (propagators) and A2 (terminators), have been isolated by fractional precipitation from oil samples, collected from Bashkirian and Vereiskian deposits of carbonate reservoirs of the Akanskoe oilfield in Tatarstan, and subjected to thermolysis at 330°C. For each oil sample, a comparative analysis of the distribution of biomarker hydrocarbons (n-alkanes, isoprenanes, steranes, and terpanes) in the original crude oil and the products derived by thermolysis of its initial asphaltene fraction and asphaltenes of both types A1 and A2 has been performed. Hydrocarbon (HC) biomarkers have been analyzed by capillary gas-liquid chromatography and gas chromatography-mass spectrometry. It has been found that the maturity of organic matter (OM) evaluated in terms of the distribution of regular C29 steranes decreases in the order: initial oil → thermolysis products of initial asphaltenes → thermolysis products of type A1 asphaltenes → thermolysis products of type A2 asphaltenes. It has been shown that except for the OM maturity, geochemical conclusions based on the biomarker parameters of the thermolysis products of asphaltene fractions A1 and A2 coincide with the geochemical findings based on the distribution of biomarkers in the thermolysis products of the initial asphaltene fraction and in the crude oils.

ИССЛЕДОВАНИЕ КОНЦЕНТРАЦИОННОЙ ЗАВИСИМОСТИ ЭФФЕКТОВ СИНЕРГИЗМА И АНТАГОНИЗМА В СМЕСЯХ ЭФИРНЫХ МАСЕЛ ЛИМОНА, КОРИАНДРА И ПОЧЕК ГВОЗДИКИ

Study of antioxidant activity (AOA) of essential oils of aromatic plants is an important task for cosmetic chemistry, aromatherapy, food and perfume industry. Usually for creating the compositions in these sectors the researchers use a mixture of two or more oils, rather than the individual ones. In this case, the effects of synergism and antagonism can occur. Previously when studying mixtures of oils from clove and lemon we found a synergistic effect, which was expressed in the increase of AOA of this mixture compared with the corresponding value for the individual oils, and in the study of the mixture of oils from lemon and coriander – antagonism, leading to a sharp decrease in AOA. However, our data on AOA of essential oil mixtures were obtained by one and a sufficiently high concentration of oils in the solution. The aim of this work is to study the dependence of AOA of essential oil mixtures on their concentration in the system and to evaluate the concentration dependence of the synergism and antagonism effects in mixtures of oils. By capillary gas-liquid chromatography dependence of antioxidant activity of mixtures of essential oils from lemon (Citrus limon), coriander (Coriandrum sativum L.) and clove buds (Caryophyllus aromaticus L.), as well as synergism and antagonism oils on the concentration of their mixtures in solution was investigated. Evaluation of antioxidant properties of oil mixtures has been studied using an aldehyde/carboxylic acid assay. Trans-2-hexenal was selected to serve as the test substance. It was found that with decreasing concentration of oil mixtures in the solution, despite the difference in character of these effects, the manifestation of synergism and antagonism became less pronounced. Antagonism oils of lemon and coriander largely offset by the addition of clove oil with high antioxidant activity. The role of strong and weak antioxidants in the oil composition was revealed in synergism and antagonism of their mixtures, which gave the opportunity to clarify the mechanism of these phenomena.

ИЗУЧЕНИЕ ЗАВИСИМОСТИ АНТИОКСИДАНТНОЙ АКТИВНОСТИ ЭФИРНЫХ МАСЕЛ ПОЧЕК ГВОЗДИКИ, ЛИМОННОЙ ТРАВЫ, КАРДАМОНА И ЯГОД МОЖЖЕВЕЛЬНИКА ОТ КОНЦЕНТРАЦИИ МАСЛА МЕТОДОМ КАПИЛЛЯРНОЙ ГАЗОВОЙ ХРОМАТОГРАФИИ

In recent time the biological activity of essential oils from spicy-aromatic herbs, including the antioxidant one, have been evaluated in numerous studies. Earlier we have demonstrated high antioxidant activity of the oils contained monoterpenes, such as γ-terpinene and α-terpinolene, sesquiterpenes (zingeberene and β-caryofillene) and citral. However the concentration value of oils in the “aldehyde – essential oil” system was excessively high and the investigation of various concentrations was not carried out by us. The goal of this work was studying of the influence of oil concentration on antioxidant activity value for selected essential oils and correlation of the obtained data with a change of main antioxidants in the composition of the essential oils under study. The antioxidant properties of the essential oils from clove buds (Caryophyllus aromaticus L.), lemongrass (Cymbopogon citratus), cardamom (Elettaria cardamomum) and berries of juniper (Juniperus pinchoti) on oil concentration has been studied by capillary gas-liquid chromatography using an aldehyde/carboxylic acid assay. Trans-2-hexenal was selected to serve as the test substance. The dependence of oil antioxidant activity on its concentration was found to be closely connected with a rate of content change of main antioxidants in the composition of the essential oils under study at prolonged exposure to light. It was noted that the presence of strong antioxidants in oil composition even in relatively low quantities can significantly affect the value of their AOA and its dependence on the concentration of oil in the solution. It was observed the strong dependence «antioxidant activity – oil concentration» for clove and lemongrass oils. Low concentrations of all investigated oils, except for oil from clove buds, didn’t have an inhibiting action on the oxidation of test-aldehyde.

Distribution and composition of hydrocarbons in bottom sediments of the Shtokman deposit (Barents Sea)

The increased interest in investigation of hydrocar� bons (HCs) in Arctic seas is mostly explained by the huge oil and gas potential of the shelf and perspective exploitation of marine deposits. By now 11 oil and gas deposits have been discovered directly on the territory of the Barents Sea [1]. Intensification of oil produc� tion and transportation to the sea should result in an increase in the anthropogenic influence on the envi� ronment. In addition, we should note that HC intro� duction from sedimentary series increases in oil and gas regions [2]. The portion of filtered HCs in the World Ocean is estimated as 0.6 × 10 6 t/year, which is 46% of their total income in seawater (1.3 × 10 6 t/year from all sources in the absence of large accidents on average [3]). Oil filtration on the Russian Arctic shelf was originally described in the 16th century on the bank of the Ukhta River (northern Timan–Pechora area), where pitch lumps were found in sand [4]. Pro� cesses of such kind were later registered in the Chukhi, Bering, Barents, and Kara seas. In accounting for the high oil and gas potential of the Arctic shelf of Russia, we may assume that this natural source provides not less than 50% of the total oil introduction in the Arctic seas. Samples were collected on two polygons in the area of the Shtokman gas–condensate deposit (SGCD) in August 2010 (57th voyage of R/V “Academician Mstislav Keldysh) in order to estimate the level and composition of HCs in bottom sediments. Polygon 1 is located in the water area, where funneled deepenings of a seabed were registered (Fig. 1a); their formation may result either from melting of buried ice (potholes) or gas release on the seabed (pockmarks) [5]. Polygon 2 is located directly in the water area of the deposit (Fig. 1b). Bottom sediments were collected by a box corer and frozen at –18°C. Samples were thawed in the lab� oratory, dried at 50°C, and the fraction of 0.25 mm was separated. HCs were extracted by metylenchloride in an ultrasonic Sapfir bath, and their concentration was analyzed by IR spectrophotometry; the composi� tion of alkanes, by capillary gas–liquid chromatogra� phy; and the concentration and composition of poly� cyclic aromatic hydrocarbons (PAH), by the method of highly effective liquid chromatography. The details of methodological procedures were described in [2, 6].

Genetic variation at the FADS1-FADS2 gene locus influences delta-5 desaturase activity and LC-PUFA proportions after fish oil supplement

Delta-5 and delta-6 desaturases (D5D and D6D) are key enzymes in endogenous synthesis of long-chain PUFAs. In this sample of healthy subjects (n = 310), genotypes of single nucleotide polymorphisms (SNPs) rs174537, rs174561, and rs3834458 in the FADS1-FADS2 gene cluster were strongly associated with proportions of LC-PUFAs and desaturase activities estimated in plasma and erythrocytes. Minor allele carriage associated with decreased activities of D5D (FADS1) (5.84 × 10(-19) ≤ P ≤ 4.5 × 10(-18)) and D6D (FADS2) (6.05 × 10(-8) ≤ P ≤ 4.20 × 10(-7)) was accompanied by increased substrate and decreased product proportions (0.05 ≤ P ≤ 2.49 × 10(-16)). The significance of haplotype association with D5D activity (P = 2.19 × 10(-17)) was comparable to that of single SNPs, but haplotype association with D6D activity (P = 3.39 × 10(-28)) was much stronger. In a randomized controlled dietary intervention, increasing eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) intake significantly increased D5D (P = 4.0 × 10(-9)) and decreased D6D activity (P = 9.16 × 10(-6)) after doses of 0.45, 0.9, and 1.8 g/day for six months. Interaction of rs174537 genotype with treatment was a determinant of D5D activity estimated in plasma (P = 0.05). In conclusion, different sites at the FADS1-FADS2 locus appear to influence D5D and D6D activity, and rs174537 genotype interacts with dietary EPA+DHA to modulate D5D.

ИЗУЧЕНИЕ ЗАВИСИМОСТИ АНТИОКСИДАНТНОЙ АКТИВНОСТИ ЭФИРНЫХ МАСЕЛ ЛИМОНА, МАЦИСА, ФЕНХЕЛЯ И ЧЕРНОГО ПЕРЦА ОТ КОНЦЕНТРАЦИИ МАСЛА В СИСТЕМЕ МЕТОДОМ КАПИЛЛЯРНОЙ ГАЗОВОЙ ХРОМАТОГРАФИИ

In recent time the biological activity of essential oils from spicy-aromatic herbs, including the antioxidant one, have been evaluated in numerous studies. Earlier we have demonstrated the high antioxidant activity of the oils contained monoterpenes, such as γ-terpinene and α-terpinolene, or sesquiterpenes (zingeberene and β-caryofillene). However the concentration value of oils in the «aldehyde – essential oil» system was too high and the investigation of various concentrations was not carried out by us. The goal of this work was studying of the influence of oil concentration on antioxidant activity value for selected essential oils. The antioxidant properties of the essential oils from lemon ( Citrus limon ), mace ( Myristicia fragans L.), fennel ( Foeniculum officinale ) and black pepper ( Capsicum nigrum L.) have been studied in a wide interval of oil concentrations by capillary gas-liquid chromatography, using an aldehyde/carboxylic acid assay. Trans -2-hexenal was selected to serve as the test substance. The dependence of oil antioxidant activity on its concentration was found to be closely connected with a rate of content change of main antioxidants in the composition of the essential oils under study at prolonged exposure to light. It was observed the strongest dependence «antioxidant activity – oil concentration» for lemon oil, while fennel oil possessed the weakest one. The low concentrations of oil from black pepper did not inhibit the aldehyde oxidation.

Plasma Phospholipid Omega-3 Fatty Acids and Freshwater Fish Consumption in the Brazilian Amazon

Background: Amazonian riverside communities consume large quantities of freshwater fish, comparable to marine fish consumption of Inuit, Scandinavian and Japanese populations. Few studies have considered the relation of high freshwater fish consumption and intake of omega-3 fatty acids (FA). Objective: The objective of the present study was to determine the profile of the concentrations of plasma phospholipid FAs and its relation with freshwater fish intake in 12 riverside communities in the Tapajos River basin (State of Para, Brazilian Amazon). Design: This cross-sectional study included 333 adults (15 - 86 years old). Fish meal frequency was determined using a 7-day interview-administered dietary recall questionnaire. Fish were categorized as piscivorous and non-piscivorous fish on trophic level. Plasma phospholipid FAs were measured by capillary gas-liquid chromatography. Results: Participants consumed 5 to 6 fish meals a week, with twice as many non-piscivorous fish than piscivorous fish (4.4 fish/week vs 2.2 fish/week, respectively). The omega-3 FA levels in plasma phospholipids were low (EPA + DHA = 31.21 mg/L; %EPA + DHA = 2.59%). Omega-3 FAs increased with frequency of fish intake, and particularly with piscivorous fish, controlling for sociodemographic, anthropometric and lifestyle characteristics. DHA levels were greater in women than in men. Conclusions: Omega-3 FA in this Amazonian population increased with fish consumption, but although they consumed freshwater fish almost daily, the concentrations of omega-3 FA were relatively low and comparable to fish-eater communities for which fish is not a dietary mainstay. It is possible that nutrients present in marine, but not in certain freshwater fish species, may facilitate absorption of omega-3 FA. Sex and/or gender differences must be taken into account when assessing the relationship between fish consumption and plasma phospholipid omega-3 FA levels.

Relation Between Dietary Fat Intake Type and Serum Fatty Acid Status in Children With Cystic Fibrosis

Children with cystic fibrosis (CF) and pancreatic insufficiency (PI) are at risk for fatty acid (FA) abnormalities and essential FA deficiency, with low linoleic acid (LA) and docosahexaenoic acid (DHA) concentrations and abnormal triene:tetraene (T:T) and arachidonic acid (AA):DHA ratios. The aim of the article was to determine whether type of dietary fat predicted serum LA, DHA, T:T, and AA:DHA ratios in subjects with CF and PI as compared to an unaffected comparison group. Serum FA concentrations were assessed by capillary gas-liquid chromatography (mol%) and dietary intake by 7-day weighed food records; the 3-day coefficient of fat absorption was calculated. Total energy intake was expressed in kilocalories. A total of 65 subjects with CF and PI (8.4 ± 1.0 years, 32 girls) and 22 controls (8.5 ± 1.1 years, 13 girls) were included. Despite greater energy, saturated fat, and LA intake, the subjects with CF had lower serum LA and DHA and higher T:T and AA:DHA than those in the comparison group. Dietary total fat, monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA), LA, total ω 6 polyunsaturated fatty acid (Tω6PUFA), and α-linolenic acid (ALA) intake positively predicted serum LA concentration. MUFA, total ω 3 polyunsaturated fatty acid (Tω3PUFA), and ALA intake positively predicted serum DHA concentration. Total dietary fat, MUFA, PUFA, Tω3PUFA, LA, and ALA intake negatively predicted serum T:T. ALA and Tω3PUFA intake negatively predicted serum AA:DHA. Dietary fat patterns influenced serum LA, DHA, T:T, and AA:DHA in children with CF and PI. These data suggest that changes in dietary practices may result in FA profiles associated with improved clinical outcomes.

Henry’s constants and activity coefficients of some organic solutes in 1-butyl,3-methylimidazolium hydrogen sulfate and in 1-methyl,3-trimethylsilylmethylimidazolium chloride

Using a customized capillary gas–liquid chromatography column, Henry’s constants and activity coefficients at infinite dilution are reported for benzene, toluene, ethyl acetate, 1,4-dioxane, 1,2-dimethoxyethane, acetonitrile, nitromethane, tetrahydrofuran, chloroform, methanol, ethanol, and 1-propanol in ionic liquids 1-butyl,3-methylimidazolium hydrogen sulfate [BMIM][HSO4] and 1-methyl,3-trimethylsilylmethylimidazolium [SiMIM][Cl] chloride from 313 to 413K. These acidic ionic liquids may provide suitable media for acid-catalyzed chemical reactions.

Evaluation and Quantitation of Intact Wax Esters of Human Meibum by Gas-Liquid Chromatography-Ion Trap Mass Spectrometry

Wax esters (WE) of human meibum are one of the largest group of meibomian lipids. Their complete characterization on the level of individual intact lipid species has not been completed yet. We obtained detailed structural information on previously uncharacterized meibomian WE. Intact WE were separated and analyzed by means of high-temperature capillary gas-liquid chromatography (GLC) in combination with low voltage (30 eV) electron ionization ion trap mass spectrometry (ITMS). 3D (mass-to-charge ratio [m/z] versus lipid sample weight versus signal intensity) calibration plots were used for quantitation of WE. We demonstrated that GLC-ITMS was suitable for analyzing unpooled/underivatized WE collected from 14 individual donors. More than 100 of saturated and unsaturated WE (SWE and UWE, respectively) were detected. On average, UWE represented about 82% of the total WE pool. About 90% of UWE were based on oleic acid, while less than 10% were based on palmitoleic acid. The amounts of poly-UWE were <3% of their mono-UWA counterparts. SWE were based primarily on C(16)-C(18) fatty acids (FA) in overall molar ratios of 22:65:13. A pool of C(16:0)-FA was comprised of a 20:80 (mol/mol) mixture of straight chain and iso-branched isomers, while the corresponding ratio for C(18:0)-FA was 43:57. Interestingly, C(17:0)-FA was almost exclusively branched, with anteiso- and iso-isomers found in a ratio of 93:7. GLC-ITMS can be used successfully to analyze more than 100 individual species of meibomian WE, which were shown to comprise 41 ± 8% (wt/wt) of meibum, which made them the largest group of lipids in meibum.

Indirect Determination of Vapor Pressures by Capillary Gas–Liquid Chromatography: Analysis of the Reference Vapor-Pressure Data and Their Treatment

Knowledge of low vapor pressures p0 is indispensible for modeling the fate of chemicals in the environment as well as for other important applications. The indirect determination of vapor pressures by the capillary gas–liquid chromatography–relative retention time (GLC–RT) technique has attracted the attention of many research groups, and two review papers devoted to this topic have already been published. To complement these reviews, the quality of the literature vapor pressures for reference compounds is analyzed, along with the influence of the equations used for the temperature dependence of p0 and the effects of the extrapolation interval applied. Since the GLC–RT techniques yield p0 of subcooled liquid even in the case of solid samples, different approaches employed for the recalculation of solid vapor pressures for reference compounds to the values for subcooled liquids are discussed. It is shown that a selection and/or application of the physicochemical properties of the reference compounds can si...

The influence of the composition of essential lemon oils on their antioxidant properties and the stability of the components

The antioxidant properties of various essential oils of lemon (Citrus limon L.) were studied by capillary gas liquid chromatography and compared with those of individual limonene and citral and their mixture in model systems. Some differences in resistance towards oxidation of the major components of lemon oils were ascertained and the synergetic effects in the antioxidant activity of the components and their stability were found.

Comparison of geometrical isomerization of unsaturated fatty acids in selected commercially refined oils

Four different commercially refined vegetable oils were analyzed by capillary gas-liquid chromatography for their trans fatty acid contents. The results obtained showed that the total trans FA contents in refined sunflower, corn, soybean, and hazelnut oils were 0.68 ± 0.41, 0.51 ± 0.24, 1.27 ± 0.57, and 0.26 ± 0.07% of total FA, respectively. The total trans FA comprised isomers of the C18:1, C18:2 and C18:3 FA. Meanwhile, five brands of the refined sunflower oil and two brands of hazelnut oil contained no measurable amounts of total trans C18:3 acids. The total trans C18:2 acid was the predominant trans FA found in the refined sunflower and corn oils, while trans polyunsaturated FAs for the refined soybean oils were found at high levels. However, total trans C18:1 acid was the major trans FA for refined hazelnut oils. The commercially refined vegetable oils with a relatively high total polyunsaturated FA contained considerable amounts of trans polyunsaturated isomers. This study indicates that it is necessary to optimize industrial deodorization, especially the time and temperature, for each different FA composition of oil used.