Capillary Column Gas-liquid Chromatography Research Articles

An efficient method for simultaneous detection of Pheniramine, Pentazocine and cotinine in urine by Gas Chromatography in De-addiction program.

Nonmedical use of prescription drugs for recreational purposes is a major health problem that raises high concerns for public health. Recently, several laboratory studies have reported the misuse of pentazocine, an agonist-antagonist opioid in combination with antihistamines in opioid addicts. Illicit self-administration of prescription drugs has been increasingly reported in India. Urinalysis as an adjunct to self-report plays a key role in providing additional information in the treatment of drug users. This paper aims to discuss a simple, convenient, and rapid capillary column gas-liquid chromatography method for simultaneous detection of pentazocine, pheniramine, and cotinine in urine. The sample was extracted with chloroform and isopropanol (3:1,v/v) and evaporated to dryness. After reconstitution with methanol, it was directly subjected to gas chromatography analysis. Method performance was evaluated and validated in terms of sensitivity, precision, the limit of detection (LOD), and the limit of quantification (LOQ). The linearity obtained was in the range of 50-1000 ng/ml with a correlation coefficient (r) above 0.999 for each drug. Good LOQ (50ng/ml) was obtained with each drug. Also, the developed method was effective in analyzing samples from patients with suspected abuse of these drugs. The technique was found to be simple, robust, sensitive, and precise in the simultaneous analysis of drugs (pentazocine, pheniramine, and cotinine). This method was proved to be useful and cost-effective in treating and monitoring patients seeking help for addiction in clinical settings.

Applicability of Capillary Gas-Liquid Chromatography for Determination of Parabens in Pharmaceutical Analysis

The traditional gas-liquid chromatography (GLC) method using packed columns is still used in pharmaceutical analysis for determination of parabens, despite the fact that this technique has a number of serious drawbacks.The aim of the study was to develop a more effective capillary GLC method for determination of parabens in active pharmaceutical ingredients and finished pharmaceutical products.Materials and methods: the study was performed using Agilent 6890N and Agilent 7890B systems with flame-ionisation detectors. The systems were equipped with Agilent 7683B and Agilent G4513A autosamplers, respectively. The following columns were used in the study: ZB-1 15 m х 0.32 mm х 0.25 pm, DB-1 30 m х 0.32 mm х 3.0 pm, Cp-Sil 5-CB 30 m х 0.32 mm х 3.0 pm.Results: the authors developed a method for methylparaben and propylparaben determination using capillary column GLC. The chromatographic parameters (chromatographic system performance, reproducibility of peak areas, peak asymmetry) were determined for both capillary and packed column GLC. The authors outlined the prospects for simultaneous determination of several compounds using the proposed method: a four-component mixture containing methyl-, ethyl-, propyl-, and butylparaben was separated in 9 minutes. The authors used Loma Lux Psoriasis to perform partial validation of the test method. They determined the linearity range and the limit of quantitation for methylparaben and propylparaben, and verified accuracy and intermediate precision of the test method.Conclusions: the results of the study allowed for selection of optimal chromatographic conditions for rapid and high-precision determination of methylparaben and propylparaben in medicinal products. The developed method is recommended for control of the content of these compounds in medicinal products.

Can long chain n-3 fatty acids from feed be converted into very long chain n-3 fatty acids in fillets from farmed rainbow trout (Oncorhynchus mykiss)?

The link between the basic chemical and fatty acid composition of trout feed on one hand and trout (Oncorhynchus mykiss) meat (fillet) was investigated.. The content of 52 fatty acids from feed and trout meat lipids was determined by in-situ transesterification and capillary column gas-liquid chromatography. On average, 100 g of trout feed contained 7.4 g of moisture, 47.7 g of proteins, 6.09 g of ash, 21.4 g of fat, and as for fatty acid composition, 47.8 wt. % were monounsaturated, 34.0 wt. % were polyunsaturated and 18.1 wt. % were saturated fatty acids, with the PS ratio 1.88, n-6/n-3 ratio 1.74, 0.80 wt. % of trans and 3.28 wt. % of very long chain n-3 fatty acids. On average, 100 g of trout meat contained 76.1 g of moisture, 21.4 g of proteins, 1.34 g of ash, 2.52 g of fat, and in the fatty acid composition 42.1 wt. % were monounsaturated, 38.2 wt. % were polyunsaturated and 18.9 wt. % were saturated fatty acids, with the PS ratio 2.02, n-6/n-3 ratio 0.98, 0.95 wt. % of trans and 13.25 wt. % of very long chain n-3 fatty acids.

Absorption of Isosorbide Dinitrate after Administration as Spray, Ointment and Microemulsion Patch. An In-vitro Study Using the Isolated Perfused Bovine Udder

Abstract The isolated perfused bovine udder is an in-vitro model, which maintains bovine udder skin with an isolated vasculature in a viable state. Using this in-vitro model, the percutaneous absorption and metabolism of isosorbide dinitrate (ISDN) was studied. The organ was perfused with gassed Tyrode solution for up to 6 h. A region of udder skin was treated topically with 60 mg ISDN as a spray, 60 mg ISDN as an ointment and with 120mg ISDN as a microemulsion patch of 30 cm2. Spray and ointment were applied onto a skin region of 400 cm2. The concentrations of ISDN and its metabolites isosorbide-2-mononitrate and isosorbide-5-mononitrate were measured in perfusate fractions by capillary column gas-liquid chromatography with electron capture detection. Following topical administration of the different formulations, ISDN as well as its metabolites were detected in the perfusate fractions, thus demonstrating that ISDN is metabolized by the udder skin in-vitro. A maximum amount of ISDN was absorbed after administration as a spray followed by ointment and microemulsion (5, 2·5 and 1·8 μmol total organic nitrate, respectively). In contrast, the ISDN flux per cm2 skin was significantly higher after administration of the microemulsion (64·4 pmol cm−2 min−1 for the microemulsion compared with 21·9 and 10·2 pmol cm−2 min−1 for spray and ointment).

A rapid gas-liquid chromatographic method for the determination of cotinine and nicotine in biological fluids

A rapid method is described for the simultaneous measurement of nicotine and cotinine in biological fluids using capillary column gas-liquid chromatography. Using 100 microliters sample volume the lower limit of detection for both nicotine and cotinine was 100 pg mL-1, allowing the method to be used for the measurement of these compounds in both smokers and non-smokers. The extraction time is 3 min per sample, and by using multi-pipetting and vortexing systems 250 samples can be extracted per day. The average coefficient of variation over the nicotine range 1.0 to 100 ng mL-1 was 3.9% and for cotinine over the range 1.0 to 1000 ng mL-1 was 2.2%. Saliva cotinine concentrations were quantitatively related to passive exposure to parental smoking in a population study of 1118 non-smoking schoolchildren.

Variations in the fatty acid composition and nutritional value of Adriatic sardine (Sardina pilchardus Walb.) through the fishing season

We investigated the chemical composition, in terms of water, protein, ash, total fat and fatty-acid composition, of sardine meat, and estimated its nutritional value. The samples originated from Adriatic sardines (Sardina pilchardus Walb.) that were collected in the north Adriatic Sea through the winter, spring, summer and autumn seasons. The content of 20 fatty acids was determined by in-situ transesterification and capillary column gas-liquid chromatography, using nonadecanoic acid (19:0) as internal standard. The mean contents of the sardine meat were: 70.8% water, 21.0% protein, 2.5% ash and 6.4% fat. For the fatty-acid composition, 18.0% were mono-unsaturated, 42.6% polyunsaturated and 39.8% saturated. The total-fat content increased through the year, from winter to autumn (0.69 to 18.15 g/100 g meat). The fatty-acid composition in the sardine meat varied significantly, with the levels of the polyunsaturated fatty acids (4.6 g/100 g meat), and especially eicosapentaenoic acid (20:5n-3, 0.98 g/100 g meat) and docosahexaenoic acid (22:6n-3, 1.9 g/100 g meat), being the highest in autumn, before spawning. The n-6/n-3 ratio (0.13) and P/S ratio (7.6) show that sardine meat can and should be included in a balanced human diet. Considering the recommended daily intake of n-3 polyunsaturated fatty acids is 0.45 g per day for a healthy population, this would be consumed as 10 g sardine meat collected in the autumn or 100 g sardine meat collected in the winter.

Regional differences of the mouse brain in response to an α-linolenic acid-restricted diet: Neurotrophin content and protein kinase activity

Aims The purpose of this study was to determine a relatively short-term effect of feeding an α-linolenic acid (ALA, n-3)-restricted, linoleic acid (LA, n-6)-adequate diet on neurotrophin contents and protein kinase activities in brain regions of the mouse. Main methods After feeding mice a safflower oil (SAF) diet (ALA-restricted, LA-adequate) or perilla oil (PER) diet (containing adequate amounts of ALA and LA) for 4 weeks from weaning, the fatty acid compositions of brain regions were analyzed by capillary column gas–liquid chromatography, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) contents were measured using enzyme-linked immunosorbent assay. Key findings The striatum and hippocampus, but not the cerebral cortex, from the SAF group, contained a smaller amount of docosahexaenoic acid (DHA, 22:6n-3) than those from the PER group. The NGF contents in these brain regions were not different between the two dietary groups. However, the striatal BDNF content of the SAF group was significantly lower than that of the PER group. Protein kinase A, protein kinase C, and p44/42 mitogen-activated protein kinase (p44/42 MAPK) activities in brain regions showed no significant difference between the two dietary groups. However, the striatal p38 MAPK activity was significantly lower in the SAF group than in the PER group. No such differences were observed in the hippocampus or the cerebral cortex. Significance A relatively short-term feeding of an α-linolenic acid-restricted, linoleic acid-adequate diet was found to lower the DHA content, BDNF content and p38 MAPK activity in the mouse striatum.

Comparative analysis of pyrolysis oils and its subfractions under different atmospheric conditions

In this paper comparative analysis of bio-oils and their subfraction from static, sweeping gas and steam pyrolysis of apricot pulp, a food industry waste, was investigated. Experimental studies were conducted in a well-swept fixed-bed reactor with a heating rate of 5 °C min− 1, to a final pyrolysis temperature of 550 °C. The oil yield which was 22.4% at the static atmosphere reached to the value of 23.2% in the sweeping gas atmosphere by using 100 cm3 min− 1 N2 flow rate. The yield of liquid product in steam pyrolysis was higher (27.2%) than the static and inert gas atmosphere.The elemental analyses of the pyrolysis oils were determined, and the chemical compositions of the oils were investigated using chromatographic and spectroscopic techniques. The liquid products were fractionated into pentane solubles and insolubles (asphaltenes). Pentane solubles were then solvent fractionated into pentane, toluene, and methanol subfractions by fractionated column chromatograpy. The aliphatic subfractions of the oils were then analysed by capillary column gas–liquid chromatography and GC/MS. For further structural analysis, the pyrolysis oils' aliphatic, aromatic and polar subfractions were conducted using FTIR and 1H NMR spectra.

Structural Analysis of Pyrolysis Products From Pyrolysis of Hazelnut (Corylus Avellana L.) Bagasse

Fixed-bed pyrolysis biooils of hazelnut (Corylus Avellana L.) bagasse have been identified for their structures. The condensed biooils were analyzed for their properties as fuels and compared with petroleum-derived products. The biooil was analyzed by Fourier Transform infrared spectroscopy (FTIR) and 1H-NMR spectra. The biooils were fractionated into pentane solubles and insolubles. Pentane solubles were then solvent fractionated into pentane, toluene and methanol subfractions by fractionated column chromatograpy. The aliphatic subfractions of the biooils were then analyzed by capillary column gas-liquid chromatography (GC). In addition, the physical properties, higher heating value and elemental analysis of the biooil were determined. The empirical formula of biooil that has a heating value of 34.57 MJ/kg was established as CH1.45O0.33N0.127. Chromatographic and spectroscopic studies on the biooil showed that the oil obtained from hazelnut bagasse could be used as a renewable fuel and chemical feedstock.

Milk fatty acid composition of goats grazing on alpine pasture

Interest in goat keeping in Slovenia has been growing recently, particularly in areas of higher altitudes, and on remote mountain and highland pastures. No literature data was found on the chemical composition of goat's milk produced on Alpine pasture. Therefore, the aim of our study was to determine the chemical milk composition of two dairy goat flocks kept at different altitudes, with the emphasis on milk fatty acid profile. The highland flock consisted of goats of the Saanen breed grazing at an altitude of 615–630 m, while the mountain flock consisted of goats of Alpine breed grazing at an altitude of 1060–1075 m. Goat keepers in Slovenia do not like keep more than one breed of goats together. The composition, free fatty acids (FFAs) and fatty acid (FA) profile of goat's milk collected from these two flocks grazing on Alpine pasture were determined. FA composition was determined by in situ transesterification and capillary column gas–liquid chromatography. Significant differences between the flocks were found for all components analysed ( P = 0.0019 for protein, P = 0.0001 for lactose, P = 0.0020 for total solids and P = 0.0010 for FFAs), except in fat content. The relationship between the FFA content and total fat was well described by the equation: FFA (mmol/l) = −0.1127 (%) + 0.4588 fat (%) − 0.0359 fat (%) 2, with R 2 = 0.73 and a S.D. of the error of 0.097 mmol/l, n = 40, for both flocks. The most abundant FAs in the milk of both flocks were C16:0, C18:1, n−9, C14:0 and C10:0. The average content of saturated FAs was 74.52 and 73.05% in milk from the higland and mountain flocks, respectively. Three saturated fatty acids (caprylic (C8:0), capric (C10:0) and lauric acid (C12:0)), were present at significantly higher amounts in milk from the highland flock than in milk from the mountain flock. Monounsaturated FAs represented 20.49 and 22.32% and polyunsaturated FAs 3.73 and 3.24% of the milk from the highland and mountain flocks, respectively. Among the monounsaturated FAs, palmitoleic + palmitelaidic acid (16:1, n − 7) showed a significantly higher concentration in milk from mountain flock than in milk from the highland flock. The content of linolelaidic acid (18:2, n − 6) was significantly higher in comparison to milk from the highland flock. The average quantity (32 mg 100 g −1 milk) of essential α-linolenic acid (18:3, n − 3) was slightly higher in milk of the highland flock than in milk from the mountain flock (26 mg 100 g −1 milk).

Tobacco smoke exposure, wheeze, and atopy.

We investigated the effect of in utero and postnatal environmental tobacco smoke (ETS) exposure on respiratory symptoms and atopy in the first 3 years of life in children at high risk of allergic disease (both parents atopic). Three hundred and sixty-nine children were followed from birth and reviewed at ages 1 and 3 years (respiratory questionnaire, skin testing). Parental smoking questionnaires were administered, and plasma cotinine in cord and peripheral blood (at age 1 year) was measured (capillary column gas-liquid chromatography). Wheezing starting in the first year of life was significantly more common in children of smoking mothers (54.2% vs. 39.5%, P = 0.017), but not wheezing starting after age 1 year (10.8% vs. 10.9%, smoking and nonsmoking mothers, P = 0.99). Detectable cord cotinine was not associated with wheeze. More frequent wheeze in infancy was significantly more common in those with detectable 1-year cotinine (e.g., wheeze without colds, 17.8% vs. 5.6%, P = 0.02; wheeze most days, 6.5% vs. 0%, P = 0.04). ETS exposure was not associated with atopy. In the multivariate regression analysis, maternal smoking during pregnancy and/or in the first year of life remained associated with wheeze in the first year of life (odds ratio, 1.88; 95% confidence interval, 1.14-3.12; P = 0.01). ETS exposure in "high-risk" infants increases the risk of wheezing starting in the first year of life, but not after age 1 year. However, ETS exposure has little or no effect on the development of atopy. Measurement of plasma cotinine was no more useful than tobacco exposure assessment by questionnaire in our cohort.

An influence of cooking on fatty acid composition in three varieties of common beans and in lentil

The fatty acid composition of three raw and cooked freeze-dried common bean varieties (Phaseolus vulgaris), namely Cesnjevec, Semenarna 22 and Cipro, and of the lentil (Lens esculenta), var. Anicia, was determined and the influence of storage on their composition was studied. Analyses of fatty acid composition were conducted by in situ transesterification and capillary column gas-liquid chromatography. In raw milled beans average values of about 16% saturated fatty acids (SAT), 6% monosaturated fatty acids (MUFA) and 78% polyunsaturated fatty acids (PUFA) were found. Somewhat different values of 15% of SAT, 25% MUFA and 60% PUFA were found in lentil. In cooked beans the content of all fatty acids was slightly decreased. In cooked lentil the decrease was almost 50%, but the ratios of SAT, MUFA and PUFA in both cases were practically the same. After two years of storage at 4 °C the fatty acid content in raw milled beans was unchanged, but altered in cooked ones. The amounts of linoleic (18:2, n-6) and α-linolenic (18:3, n-3) acid decreased, but myristic (14:0), margaric (17:0) and arachidic (20:0) acids increased. It was found that freeze-dried cooked beans, prepared from raw seed beans, kept 2.5 years at 10 °C, have practically the same fatty acid composition as freeze-dried cooked beans 0.5 year after harvesting.

The Phytosterol Content of Some Cereal Foods Commonly Consumed in Sweden and in the Netherlands

The aim of this report was to quantify five specific dietary phytosterols and phytostanols (campesterol, β-sitosterol, stigmasterol, β-sitostanol, and campestanol) in cereal foods and to study the effect of boiling on sterol content. A capillary column gas liquid chromatography procedure was used to analyse 76 cereal food items of Swedish and Dutch origin: 19 various flours, grains and germs, 31 processed cereals, including bran, flakes, cereal grains and pasta, nine breads, and 17 biscuits, cakes, crackers, cookies and sweet breads. The median total phytosterol concentration was 49 (range 4.1–344) mg/100 g edible portion (e.p.). Flours, grains and germs had a median concentration of 52 (17–344) mg/100 g e.p., which was similar to breads, 54 (29–89) mg/100 g e.p., and different types of miscellaneous cakes and cookies, 52 (27–112) mg/100 g e.p. Processed cereal products had slightly lower concentrations with a median value of 39 (4.1–200) mg/100 g e.p. In general, β-sitosterol was the dominant phytosterol (62% of the total concentration), followed by campesterol (21%), while there were only small amounts of stigmasterol (4%), β-sitostanol (4%) and campestanol (2%). Boiling of cereal products only influenced the phytosterol concentration through change of water content.

Structural analysis of bio-oils from pyrolysis and steam pyrolysis of cottonseed cake

Structural analysis and the effect of the water vapour on the structure of the products obtained by low temperature thermal destruction of biomass at atmospheric pressure has been investigated. The liquid products were fractionated into pentane solubles and insolubles (Asphaltenes). Pentane solubles were then solvent fractionated into pentane, toluene, ether and methanol subfractions by fractionated column chromatograpy. The aliphatic subfractions of the oils were then analysed by capillary column gas-liquid chromatography and GC/MS. For further structural analysis, the pyrolysis oils and aromatic and polar subfractions were conducted using FTIR and 1H-NMR spectra.

Structural Analysis of Bio-Oils from Fixed-Bed Pyrolysis of Euphorbia rigida and Sunflower Pressed Bagasse

Fixed-bed tars of Euphorbia rigida and sunflower pressed bagasse have been investigated for their structures. These tars were fractionated into pentane-soluble and -insoluble compounds (asphaltenes). Pentane soluble were then solvent fractionated into pentane, toluene, ether, and methanol subfractions by fractionated column chromatography. The aliphatic and low-molecular-weight aromatic subfractions of the bio-oils were then analyzed by capillary column gas-liquid chromatography and GC/MS. Further structural analysis of bio-oils and aromatic and polar subfractions were conducted to FTIR and 1HNMR spectra.

Pyrolysis of hazelnut shells in a fixed-bed tubular reactor: yields and structural analysis of bio-oil

Fixed-bed pyrolysis experiments have been conducted on a sample of hazelnut shells to determine the possibility of being a potential source of renewable fuels and chemical feedstocks. The effects of pyrolysis temperature and well-sweep gas atmosphere (N 2) on the pyrolysis yields and chemical compositions have been investigated. The maximum bio-oil yield of 23.1 wt.% was obtained in N 2 atmosphere at a pyrolysis temperature of 500°C and heating rate of 7 K min −1. The pyrolysis products were characterised by elemental analysis and various chromatographic and spectroscopic techniques and also compared with currently utilised transport fuels by simulated distillation. Bio-oil was then fractionated into pentane soluble and insoluble compounds (asphaltenes). Pentane soluble was then solvent fractionated into pentane, toluene, ether and methanol subfractions by fractionated column chromatography. The aliphatic and low-molecular-weight aromatic subfractions of the bio-oil were then analyzed by capillary column gas-liquid chromatography and GC/MS. Further structural analysis of bio-oil and aromatic and polar subfractions FTIR and 1H-NMR spectra were obtained. The chemical characterization has shown that the bio-oil obtained from hazelnut shells was quite similar to the crude oil and shale oil.

Fatty acid composition of brain glycerophospholipids in peroxisomal disorders.

This paper shows for the first time the differential fatty acid composition of ethanolamine plasmalogens (EP) and phosphatidylethanolamine (PE) in the brains of 12 patients with disorders of peroxisomal biogenesis and compares the results to normal values for the age. Other important glycerophospholipids (GPL), such as phosphatidylserine (PS) and phosphatidylcholine (PC), are also included in this study. GPL were separated by two-dimensional thin-layer chromatography, and their fatty acid composition was determined by capillary column gas-liquid chromatography. Total brain GPL were slightly decreased in peroxisomal disorders (27.98+/-2.95 micromol/g in the patients against 34.5+/-6.21 micromol/g in age-matched controls, P = 0.005), and the distribution of the different GPL classes was much altered. In confirmation of known data, EP were very much decreased (2.18+/-1.3 micromol/g in the patients against 6.9+/-2.3 micromol/g in controls) at the expense of PE, which was increased (8.58+/-2.17 micromol/g in the patients against 5.97+/-0.58 micromol/g in controls, P<0.005). PS and PC were both significantly decreased (P = 0.0001 and P = 0.037, respectively). The polyunsaturated fatty acid (PUFA) composition of all the GPL fractions was markedly abnormal. In absolute terms, docosahexaenoic acid (22:6n-3) was drastically decreased in all GPL classes (always at the P<0.0001 level) while arachidonic acid (20:4n-6) was increased in PE and PS (P<0.001 in both cases). In the alkenyl acyl form, EP, 22:6n-3, and 20:4n-6 were both very significantly decreased (P<0.0001), although the former was always the most affected. The myelin PUFA adrenic acid (22:4n-6) was decreased in EP (P<0.0001) and slightly increased in PS (P<0.05). The changes found confirm that 22:6n-3 deficiency is a predominant defect in the brain in peroxisomal disorders.

An optimized method for fatty acid analysis, including quantification of trans fatty acids, in human adipose tissue by gas-liquid chromatography

Considering the need for a quick direct method for measurement of the fatty acid composition including trans isomers of human adipose tissue we have developed a procedure using gas-liquid chromatography (GLC) alone, which is thus suitable for validation of fatty acid status in epidemiological studies. Fatty acids ranging in carbon number from 12 to 22 and with 0-6 double bonds were resolved and identified by capillary column GLC with a temperature program starting at 150°C. Following injection, the oven temperature was increased at a rate of 3°C/min to 200°C, then held constant for 25 min, and finally raised at 25°C/min to 225°C. The trans and cis

Plasma and mucosal fatty acid pattern in colectomized ulcerative colitis patients.

Patients with inflammatory bowel disease (IBD) have increased plasma n3 polyunsaturated fatty acids (PUFAs), which in ulcerative colitis (UC) patients persists six months after colectomy, suggesting a primary abnormality in fatty acid (FA) metabolism in IBD. This finding needed to be confirmed in a larger series of UC long-term colectomized patients. We aimed to assess the plasma FA pattern in UC colectomized patients with either Brooke's ileostomy (UC-BI) or ileal pouch anal anastomosis (UC-IPAA) and the mucosal FA pattern in the ileal reservoir of the UC-IPAA patients. Plasma FAs were assessed in 63 UC colectomized patients (31 with BI and 32 with IPAA) and 30 controls. In 26 UC-IPAA (8 with pouchitis and 18 without pouchitis) and in 13 healthy controls gut mucosal FAs were also investigated. FAs were detected by capillary column gas-liquid chromatography. Increased levels of saturated fatty acids (SFAs) and decreased percentages of monounsaturated fatty acids (MUFAs) were observed in both groups of patients. There were no changes in plasma n3 and n6 PUFAs. The mucosal FA pattern of the ileal reservoir consisted of increased long-chain PUFAs, specially n6 PUFA, and a decrease of their essential precursors. High percentages of SFAs and low percentages of MUFAs were also seen. The plasma FA profile previously described in IBD is not observed long-term after colectomy in UC, suggesting that it is related with the presence of inflamed intestine. High concentrations of SFAs and decreased percentages of MUFAs might represent early events in disturbed FA metabolism in IBD. The changes in FAs of the ileal reservoir, which closely resemble those found in human and experimental IBD, probably represent a common pattern of intestinal inflammation.

Cuticular Hydrocarbons of Glacially-Preserved Melanoplus (Orthoptera: Acrididae): Identification and Comparison with Hydrocarbons of M. sanguinipes and M. spretus

-The cuticular hydrocarbons of four groups of grasshoppers were identified and quantified by capillary column gas-liquid chromatography (GLC) and GLC-mass spectrometry (GLC-MS), including samples of: 1) a modern species, M. sanguinipes (Fabricius), 2) a morphologically similar extinct species, M. spretus Walsh, 3) 650year old fragments recovered from a receding glacier in southwestern Montana, and 4) 140-year old whole bodies from a glacier in northwestern Wyoming. Quantitative data from 20 n-alkanes and methyland dimethyl-branched alkanes were compared using discriminant analysis, which showed differences in cuticular hydrocarbon patterns between the putative species M. sanguinipes and M. spretus. The resulting discriminant model classified the glacially preserved whole bodies as M. spretus, but the identity of the fragments remains ambiguous [