GC-FID Method Research Articles

Comparison of Fatty Acids by GC-FID Method of Grapes of Three Different Provinces in Southeastern Anatolia Region

Bu çalışmada Mardin, Diyarbakır ve Gaziantep kuru üzümlerinin yağ asit düzeyleri belirlendi. Mardin kuru üzümünün yağ asit düzeyleri ΣPUFA % 49.60, ΣMUFA % 29.61, ΣUSFA % 79.21 ve ΣSFA % 22.02 olarak, Diyarbakır kuru üzümünün yağ asit düzeyleri ΣPUFA % 22.80, ΣMUFA % 37.72, ΣUSFA % 60.58, ΣSFA % 40.45 ve Gaziantep kuru üzümünün yağ asit düzeyleri ΣPUFA % 44.77, ΣMUFA % 27.34, ΣUSFA % 72.12, ΣSFA % 28.62 olarak tespit edildi. Mardin ve Gaziantep kuru üzümünün linoleik asit (18:2n6c) düzeyi yüksek çıkarken Diyarbakır kuru üzümünün oleik asit (18:1n9c) ve palmitik asit (16:0) düzeylerinin yüksek çıktığı gözlendi.

Simultaneous Determination of Free Phytosterols and Tocopherols in Vegetable Oils by an Improved SPE–GC–FID Method

In this work, a simple and rapid SPE–GC–FID method for simultaneous determination of free tocopherols and phytosterols in vegetable oils was developed. The use of this SPE approach for the extraction of naturally occurring tocopherols and phytosterols provides advantages such as simplicity, high speed, and ease of use. The whole method was validated, and the limits of detection of tocopherols and phytosterols were 0.05 and 0.03 mg/100 g of oil, respectively. The precisions for the determination of tocopherols and phytosterols in vegetable oils were < 10.1% in relative standard deviations. The recoveries of selected tocopherols and phytosterols spiked at low, middle, and high concentrations ranged from 83.4 to 97.7%. The developed approach was successfully applied to the analysis of free tocopherols and phytosterols in rapeseed, sunflower seed, linseed, sesame, and maize oils.

The fatty acid and triacylglycerol profiles of conventionally and organically produced grains of maize, spelt and buckwheat

Triacylglycerols (TAGs) and free fatty acids (FAs) present an important part of the grain lipid fraction. Knowing about its composition can be important information for both chemotaxonomic and nutritional parameters. The aim of the present study was to determine the TAG and FA profiles (and their similarities/differences) of several important crops (maize, spelt, buckwheat) grown under dissimilar agroecological systems – conventional and organic. Fatty acid composition was determined by applying the GC-FID method while HPLC method was used for the determination of the triacylglycerol profile of selected grains. To the best of our knowledge, the TAG profile of spelt grains was determined for the first time. Ten different FAs were identified in examined samples with a predominant presence of linoleic acid, except in the case of buckwheat (oleic acid) grains. Uniformly, buckwheat grains stood out due to the predominance of triglycerides with an equivalent carbon number of fifty (ECN 50) or forty-eight (ECN 48). In contrast, other samples contained ECN 44 and ECN 46 TAGs as the most represented triglycerides. Based on the principal component analysis (PCA) and cluster statistical analysis results, there is no uniformity in the differences between organic and conventional production growing systems.

Evaluation of the Levels of Heavy Metals, Total Petroleum Hydrocarbon and Total Hydrocarbon Content in Tympanotomus fuscatus and Sediment, Qua Iboe River, Akwa Ibom State, Nigeria

This study assesses the levels of heavy metals and hydrocarbons in Tympanotomus fuscatus and the sediments of Qua Iboe River, Akwa Ibom State; the interest in the study area was due to the several industrial and oil exploration activities in the area. The heavy metals (HM) of interest were Pb, Cd, Cu, Se, Zn, As, Cr, Fe, Ni and Hg, determined using Atomic Absorption Spectroscopy while Total Hydrocarbon Content (THC) and Total Petroleum Hydrocarbon (TPH) were determined by the GC-FID method. Results obtained indicated that the heavy metal concentration in Tympanotomus fuscatus ranged as follows: Pb (1.037 – 2.002 mg/kg), Cd (0.00 – 0.088 mg/kg), Cu (0.0037 – 10.01 mg/kg), Se (2.364 – 5.063 mg/kg), Zn (0.025 – 1.393 mg/kg), As (0.0113 – 0.355 mg/kg), Cr (1.075 – 3.055 mg/kg), Fe (2.384 – 10.022), Ni (0.045 – 1.223 mg/kg), Hg (0.037 – 1.003 mg/kg) while heavy metal concentration in sediments were: Pb (1.399 – 2.345 mg/kg), Cd (0.0267– 0.222 mg/kg), Cu (0.017 – 10.0197 mg/kg), Se (1.388 – 3.369 mg/kg), Zn (5.688 – 8.038 mg/kg), As (0.003 – 0.0317 mg/kg), Cr (0.0157 – 2.057 mg/kg), Fe (27.351 – 86.686), Ni (0.017 – 5.0413 mg/kg), Hg (0.06 – 1.53 mg/kg); generally, heavy metals levels were higher in dry season than in wet season. The levels of TPH ranged from 160.86 – 1081.52 mg/kg in Tympanotomus fuscatus and 175.97 – 3143.91 mg/kg in sediments; meanwhile, the concentration of TPH ranged from 728.47 – 2442.04 mg/kg in Tympanotomus fuscatus and 492.41 – 7186.25 mg/kg in sediments. Multiple correlation coefficient matrixes were carried out to ascertain the relationship between the pollutants concentration in the biota and sediments. Furthermore, predictive modeling of pollutant concentration in flesh and shell of Tympanotomus fuscatus was estimated. The results indicate that the amounts of HM, TPH and THC in some of the study sites were above the maximum permissible limit set by WHO and FMEnv; thus, pose health risk to humans.

Health-promoting value of cow, sheep and goat milk and yogurts

The purpose of the presented study was to determine the fatty acid composition, health lipid indices content and selected micro and macronutrients in cow, sheep and goat milk and yogurts produced there of. Fatty acid composition was determined by the GC-FID method using a 100-m capillary column with CP Sil 88 phase. Microelements (iron, zinc, copper and manganese) and macroelements (magnesium and calcium) were analysed using flame atomic absorption spectrometry, whereas sodium and potassium were determined by the emission method. Phosphorus was analysed by the colorimetric method. The conducted study demonstrated that sheep, cow and goat milks and yogurts were characterized by different contents of fatty acids, micro- and macroelements. Sheep milk and yogurts could be regarded as richer sources of polyunsaturated fatty acids (PUFA), (4.41 and 4.35 % of total fatty acids, respectively), n-3 fatty acids (1.05 % of total fatty acids). These samples also had lower n6/n3 ratio (1.93 and 1.92, respectively) and the lowest value index of Thrombogenicity (TI) in comparison to the other analyzed milk and yogurt samples. In turn, goat milk and yogurts were characterized by the highest content of short-chain fatty acids (SCFA), (18.07 and 18.17 % of total fatty acids, respectively) the lowest content of saturated fatty acids (SFA), (54.62 and 54.93 %, respectively) and the lowest value index of Atherogenicity (AI) (2.79 and 2.84, respectively). Concentrations of all analyzed microand macroelements were significantly (P&amp;lt;0.05) higher in yogurts than in milk samples used for their production. Goat yogurts contained higher concentrations of copper, iron, and potassium compared to sheep and cow yogurts. In turn, sheep yogurts had more zinc, magnesium, calcium, and phosphorus than the other analyzed yogurt samples.

Development and validation of a GC-FID method to quantify thymoquinone in black cumin seed oils

Development and validation of a GC-FID method to quantify thymoquinone in black cumin seed oils

Styrene monomer migration from polystyrene based food packaging nanocomposite: Effect of clay and ZnO nanoparticles

Inhibition from migration of plastic ingredients such as styrene monomer (SM) is very important in food packaging industry. Styrene monomer is one of the substances which can potentially migrate from polystyrene based packaging. In the present study, organoclay and zinc oxide nanoparticles (ZnO-NPs) were used for decreasing of the SM migration into food simulants (10 and 50% ethanol (v/v)). A used GC–FID method for measuring of the migrated SM showed good precision and accuracy. Maximum reduction of SM migration into 10% and 50% ethanol (24 h storage at 40 °C) were observed in the polystyrene/nanoclay and polystyrene/ZnO samples, respectively. The SM migration data in 50% ethanol at 5 °C followed from Fickian diffusion law and the lowest diffusion coefficient (2.89 × 10−14 cm2/s) was observed in the polystyrene/ZnO/nanoclay samples.

Simultaneous GC-FID Quantification of Main Components of Rosmarinus officinalis L. and Lavandula dentata Essential Oils in Polymeric Nanocapsules for Antioxidant Application.

The essential oils (EO) of R. officinalis and L. dentata have been widely used due to their antioxidant activity. However, due to their high volatility, the loading of EO into polymeric nanocapsules (NC) represents an efficient way of retaining their effect in future topical administration. In this way, the quantitative determination of EO incorporated into NC is necessary for simultaneous monitoring of the main components of the EO during the nanoencapsulation process as well as for precise and exact dosing of the components used during the performance of in vitro and in vivo biological tests. In this study, EO were isolated by hydrodistillation in a Clevenger-type apparatus and characterized by GC-MS and GC-FID analyses. The major constituents of EO-R. officinalis were camphor (39.46%) and 1,8-cineole (14.63%), and for EO-L. dentata were 1,8-cineole (68.59%) and β-pinene (11.53%). A new analytical method based on GC-FID for quantification of free and encapsulated EO was developed and validated according to ICH. Linearity, limit of detection and quantification, and intra- and interday precision parameters were determined. The methods were linear and precise for the quantification of the main components of EO. The EO were encapsulated by nanoprecipitation and were analyzed by the GC-FID method validated for their direct quantification. The NC size was 200 nm with homogeneous size distribution. The quantification of the incorporated EO within a NC is an important step in NC characterization. In this way, an encapsulation efficiency of at least 59.03% and 41.15% of total EO-R. officinalis and EO-L. dentata, respectively, was obtained. Simple, repeatable, and reproducible methods were developed as an analytical tool for the simultaneous quantification of the main components of EO loaded in polymeric nanocapsules as well as their monitoring in biological assays.

Physicochemical characterization, fatty acid in Corn Seed Oil using GC-FID method

Physicochemical characterization, fatty acid in Corn Seed Oil using GC-FID method

Evalution of fatty acid compositions and physicochemical quality parameters of ancient and recent olive (Olea europaea L.) oil varieties of Southeast Anatolia

Upper Mesopotamia is known to be the homeland of olive, spanning over Mardin, Hatay, Kilis and the western shores of Syria and Palestine. Having earliest habitation in the Southeastern Anatolia region, olive lies down along the Western Anatolia. The goal of the present study is to evaluate the fatty acid compositions of the olive oils obtained from the olive trees which are the kinds of Kilis yağlık (KY), Halhalı (H), Gemlik-Kilis (GK), and Gemlik-Gemlik (GG). While GG variety has the lowest total saturated fatty acids (SFAs), KY, GK and H varieties show similarity in respect to the total SFAs levels, and these have the higher SFAs levels. While GG variety has the lowest total SFAs and polyunsaturated fatty acids (PUFAs), KY contains the highest total SFAs and PUFAs. While mean docosahexaenoic acid (DHA) values in KY and GK varieties are minor levels, it is found below the detection limit of GC-FID method for all of H and GG samples.

PSIV-24 GC-FID method validation of DHA in swine feed supplemented with heterotrophically grown, dried microalgae powder (All-G-Rich®).

PSIV-24 GC-FID method validation of DHA in swine feed supplemented with heterotrophically grown, dried microalgae powder (All-G-Rich®).

PSX-16 GC-FID method validation and stability assessment of DHA in swine tissues.

PSX-16 GC-FID method validation and stability assessment of DHA in swine tissues.

Effect of mcl-PHA synthesis in flax on plant mechanical properties and cell wall composition

The high demand for new biomaterials makes synthesis of polyhydroxyalkanoates (PHA) in plants an interesting and desirable achievement. Production of polymers in plants is an example of application of biotechnology for improving the properties of plants, e.g. industrial properties, but it can also provide knowledge about plant physiology and metabolism. The subject of the present study was an industrially important plant: flax, Linum usitatissimum L., of a fibre cultivar (cv Nike). In the study the gene encoding PHA synthase from Pseudomonas aeruginosa, fused to a peroxisomal targeting signal, was expressed in flax plants with the aim of modifying the mechanical properties of plants. Medium-chain-length (mcl) hydroxy acids in flax plants from tissue cultures were detected by GC-FID and FTIR method. The introduced changes did not affect fatty acid content and composition in generated flax plants. Since mcl-PHA are known as elastomers, the mechanical properties of created plants were examined. Modified plants showed increases in the values of all measured parameters (except strain at break evaluated for one modified line). The largest increase was noted for tensile stiffness, which was 2- to 3-fold higher than in wild-type plants. The values estimated for another parameter, Young’s modulus, was almost at the same level in generated flax plants, and they were about 2.7-fold higher when compared to unmodified plants. The created plants also exhibited up to about 2.4-fold higher tensile strength. The observed changes were accompanied by alterations in the expression of selected genes, related to cell wall metabolism in line with the highest expression of phaC1 gene. Biochemical data were confirmed by spectroscopic methods, which also revealed that crystallinity index values of cellulose in modified flax plants were increased in comparison to wild-type flax plants and correlated with biomechanical properties of plants.

Chemical Composition and Antibacterial Activity of the Essential Oil of Menthae piperitae L.

The subject of this study was the examination of the chemical composition and antimicrobial activity of peppermint oil (Menthae piperitae L.), that was produced from the plant collected from the plantation in the city of Banja Luka. To examine the chemical composition of the Mentha piperita essential oil we used the GC-FID method. On it’s chromatogram it was clearly shown that the main components of the oil were menthole with the content of 43.66%, menthone 20.02%, iso-menthone 7.73%, following by 1,8-cineole with a percentage of 6.49% and menthil-acetate with 3.31%. The content of the previously mentioned components were all in accordance with the suggestions made by Ph.Eur 8.0. For the purpose of examination antimicrobial activity of the peppermint oil we used agar diffusion method. The results have shown that etheric oil of Menthae piperitae reflects very good antimicrobial activity on all bacterial cultures that we used in this study. The inhibiton zones moved from 12 mm for Pseudomonas aeruginosa to 37.66 mm for Staphylococcus aureus. Such an outcome of our study, and many others from all around the world, indicates the future potential use of peppermint oil in the treatment of bacterial infections, maybe even lowering the use of antibiotics.

Development and Validation of a GC-FID Method for Determination of Cocaine in Illicit Drug Samples

Development and Validation of a GC-FID Method for Determination of Cocaine in Illicit Drug Samples

Testing Utility of Organogeochemical Proxies to Assess Sources of Organic Matter, Paleoredox Conditions, and Thermal Maturity in Mature Marcellus Shale

It is generally accepted that in mature shales, biomarkers and pyrolysis proxies are not very helpful in understanding the source/type of organic matter (OM), paleo-redox conditions during deposition and thermal maturity. The purpose of the study study was conducted to test the efficacy of these proxies in mature Marcellus shale (VRo> 1). Samples were collected from oil-prone (WV-7) and gas-prone (WV-6) wells in Wetzel and Monongalia Counties, West Virginia, respectively. These wells were chosen for this test study because high-resolution geochemical and isotopic studies have previously been conducted on these cores and depositional model had been proposed. The model suggests that sediments in WV-6 well are more mature, received higher terrestrial OM influx and were deposited in less anoxic environment as compared to WV-7 well. We used an improved method to extract the small amount of biomarkers preserved in the samples. Further, the extracts were analyzed by a high-resolution GC×GC FID method to quantify the distribution of aliphatic biomarkers. The hydrogen and oxygen indices (HI vs. OI plot) determined by Source Rock Analysis could not be used to determine the kerogen type due to their very low values. However, interpretations were derived from S1 vs. S2 and S2/S3 vs. TOC cross plots, thermal maturity parameter (Tmax), fraction conversion of OM to hydrocarbon (HC), and residual carbon/pyrolysable carbon (RC/PC) ratio. The conclusions drawn from the biomarkers and SRA data are in agreement with the HC production data from these wells as well as interpretations derived from geochemical and isotopic studies conducted on these core. Therefore, we propose that despite some limitations biomarker and pyrolysis proxies can be used to determine the thermal and depositional history of mature shales like the Marcellus Shale.

TRIMETHYLAMINE AS A FRESHNESS INDICATOR FOR SEAFOOD STORED IN ICE: ANALYSIS BY GC-FID OF FOUR SPECIES CAUGHT IN THE TYRRHENIAN SEA

In seafood products Trimethylamine (TMA) is an indicator of the conservation status. In freshly caught samples it is almost absent and its content increases during spoilage. In the present work a new and easy GC-FID method with a commercial capillary column, specifically designed, is applied. TMA was measured at increasing time intervals in four marine species caught in the Tyrrhenian Sea and stored in ice, for a total of 852 individuals analyzed. For each species an assessment about the maximum allowable time of storage in ice was made. Existing guidelines about the level of Trimethylamine are reviewed and discussed.

Fast approach for fatty acid profiling of dairy products fats using 1H-NMR spectroscopy

A quick and modern alternative for the analysis of milk-based products is proposed. The fats from hard and white fermented cheese samples were extracted and examined using NMR. The identification and quantification of the fatty acid profile was based on a set of chemometric equations. At the same time, based on the ratio of long chain (C10–C22) saturated fatty acids to short chain (C4–C8) fatty acids, the suspected adulteration with vegetable fats could be quickly established (the ratio varied with the addition of exogenous fats). The accuracy of the results offered by NMR method was confirmed by a standard GC-FID method.

Validation of a gas chromatography-flame ionization method for quality control and spoilage detection in wine and cider

A GC-FID method for major volatile analysis in cider and wine was validated under the requirements of the ISO/IEC 17025 regulation using a split mode injection. This method presented a good linearity (R2&gt;0.999, Cm&gt;99%), a wide range of calibration, the maximum random errors for repeatability and intermediate precision were 5% and 8%, respectively, and the maximum limit of quantification and limit of detection were 14.1 mg l–1 and 4.6 mg l–1, respectively. Trueness, expressed as recovery (%), was successfully validated by means of two different methods, standard addition (92–110%) and comparison against reference materials (93–115%). Expanded uncertainty estimated at 95% confidence level ranged between 11% for methanol and 7% for allyl alcohol. The validated method was successfully applied for the analysis of major volatiles in ciders and wines, and to detect yeast and lactic acid bacteria spoilage.

Development of a coupled dispersive liquid-liquid micro-extraction with supported liquid phase micro-extraction for triclosan determination in wastewater

As attention is drawn towards the monitoring of the so-called emerging pollutants, some common household chemicals are not well researched. Household antimicrobials can also present wastewater treatment challenges if not taken cognisance of. Herein we report the application of a recently reported coupled dispersive liquid-liquid micro-extraction (DLLME) with supported liquid phase micro-extraction (LPME) for the extraction of triclosan from wastewater. A univariate approach was used to investigate various parameters amenable to DLLME while no attempt was made to optimise the LPME, achieving the following optimum conditions: 25 μL of a 1:1 toluene-chloroform mixture with 10% sodium chloride into 1 mL aqueous triclosan solutions and extraction time of 15 min achieving an enrichment efficiency 167 times the reference solution prepared with distilled water, good linearity (R2 = 0.9946) with the estimated limit of detection at 0.013 μg/mL and good repeatability (%RSD ≤ 10). The method showed considerable ruggedness with a similar linearity (R2 = 0.9957) and repeatability (%RSD &lt; 10), with only the limit of detection being compromised (0.31 μg/mL) when applied to a wastewater sample using a matrix-matched standard addition approach. Although the GC-FID method detected triclosan in the wastewater sample, the results were negated by those from the GC-MS; as such it therefore could not be concluded with confidence whether the water contained any triclosan or not. However, the results demonstrated the potential of this method in determination of triclosan in water-based samples when the extraction was coupled to a more rugged system such as a GC-MS.