Gas Chromatography Coupled To A Flame Ionization Detector Research Articles

Composición química y actividad Butirilcolinesterasa selectiva del aceite esencial de Piper arboreum Aubl. de Ecuador

The aim of this study was to identify the chemical composition of the Piper arboreumAubl. essential oil (EO), and to evaluate its inhibitory activity in vitroagainst the enzymes butyrylcholinesterase (BuChE) and acetylcholinesterase (AChE). The EO was obtained by steam distillation of the leaves, which were collected in Pindal canton of the Loja province in southern Ecuador. The chemical composition was analyzed using the gas chromatography technique coupled to a mass spectrometry detector (GC-MS) and gas chromatography coupled to a flame ionization detector (GC-FID). A total of 41 compounds were identified, the major components found in the oil were limonene (31,46%), β-selinene (12,01%), (E)-caryophyllene (7,53%), bicyclogermacrene (6,72%), germacrene D (3,83%) and β-elemene (3,63%). In in vitro analyzes, the EO showed high selective inhibition for BuChE with an IC50inhibition value of 29,3±3,3 μg/mL. By contrast, the EO was not active against the AChE enzyme (IC50was 100,1±15,2 μg/mL).

Lipid profile and cost of enteral nutrition formula with addition of fish oil used in a public hospital

Background & aimsThe present study evaluated the lipid profile of enteral nutrition formulas with added fish oil used in a public hospital, with an emphasis on the fatty acid (FA) composition. MethodsFA composition was determined using gas chromatography coupled to a flame ionization detector (GC-FID). Nine enteral nutrition formulas were evaluated and the results obtained were compared with those reported on the formulas labels. ResultsThe sample with the highest percentage of added fish oil according to the label information had the lowest total amounts of eicosapentaenoic acid and docosahexaenoic acid (EPA + DHA) (p < 0.05). In the evaluation of the total amount of polyunsaturated fatty acids/saturated fatty acids (ΣPUFA/ΣSFA) ratio, five samples were not within the values recommended by Brazilan and international health regulatory agencies. Regarding the n-6/n-3 fatty acids ratio, five samples showed values higher than the recommended ratio. It was observed that EPA + DHA content was positively correlated with the cost of the diet. Importantly, we also found that there was a significant difference between the results of our analysis and the descriptions found on the labels for fatty acids n-6, n-3, EPA, DHA, SFA, PUFA and MUFA. ConclusionsWe conclude that the discrepancies for fatty acids between the values obtained in the analyses and the values reported on the labels highlight the need for more rigorous inspection when public hospitals purchase enteral nutrition formulas with added fish oil, since the administration of formulas with inadequate levels of FA in hospitalized patients can compromise clinical results during the hospitalization period.

Modification of Antibiotic Activity by Fixed Oil of the Artocarpus heterophyllus Almond against Standard and Multidrug-Resistant Bacteria Strains.

Artocarpus heterophyllus (jackfruit) is an evergreen tree distributed in tropical regions and is among the most studied species of the genus Artocarpus. The jackfruit almond has been highlighted in relation to phytochemical studies, biological properties, and application in the development of food products. This study aimed to analyze jackfruit fixed oil regarding chemical components, antibacterial property alone, and in association with antibiotics against standard and MDR bacteria strains. In the analysis of the oil by gas chromatography coupled to a flame ionization detector (GC-FID), a high content of saturated fatty acids (78.51%) was identified in relation to unsaturated fatty acids (17.07%). The main fatty acids identified were lauric acid (43.01%), myristic acid (11.10%), palmitic acid (6.95%), and oleic acid (15.32%). In the antibacterial analysis, broth microdilution assays were used. The oil presented minimum inhibitory concentration (MIC) ≥ 1024 μg/mL in antibacterial analysis for standard and MDR bacterial strains. The oil showed synergistic effects in the association with gentamicin, ofloxacin, and penicillin against MDR strains, with significant reductions in the MIC of antibiotics. The results suggest that the fixed oil of A. heterophyllus has fatty acids with the potential to synergistically modify antibiotic activity.

Suicide of a young woman using a kit containing sodium nitrite ordered on the internet

We report the case of a 13-year-old girl, found dead by her father, with a glass containing 15 g of white powder and a bottle containing 5 g of white powder with a moistened appearance. The autopsy was performed four days after the death. The anatomopathological study of the specimens was included in formaldehyde and prepared according to the Saffron Eosin Hematein technique. First of all, a post-mortem toxicological screening was performed on cardiac blood, peripheral blood, urine and gastric contents by high performance liquid chromatography coupled to high resolution mass spectrometry (HPLC-HRMS). Ethanol testing was performed by gas chromatography coupled to a flame ionization detector (GC-FID), and drug testing by liquid chromatography coupled to a mass spectrometer (LC-MS/MS, opiates, cocaine, amphetamine) or gas chromatography coupled to a mass spectrometer (GC-MS, cannabis). A rapid analysis of powders found near the body was carried out by RAMAN spectrometry, and confirmed by ion chromatography coupled with mass spectrometry and X-ray diffractometry. In order to establish the concentration of the substance found by those analyses in peripheral blood and gastric contents, we later used the saltzman reaction after addition of potassium ferrocyanide and zinc sulfate. External examination and autopsy revealed a non-specific asphyxia syndrome. This was confirmed by the anatomopathological study which showed signs of non-specific acute heart failure: diffuse visceral congestion (heart, lungs, spleen, liver, pancreas, kidneys, thyroid, stomach) and pulmonary haemorrhage. First of all, toxicological analyses revealed the presence of metoclopramide, in cardiac blood (0.37 mg/L), urines (0.20 mg/L), gastric contents (0.24 mg/L) and in peripheral blood at a concentration of 0.40 mg/L. However, no ethanol and presence of drugs of abuse (cannabinoids, opiates, cocaine, and amphetamines) were detected. Secondly, powders found close to the body were analysed by three different techniques, and revealed the presence of sodium nitrite in pure form. Finally, the analysis of gastric contents confirmed the presence of nitrites at a concentration of 30.9 mg/L. This analysis could not be performed on the blood samples due to colour interference. This young girl died of anoxia secondary to the ingestion of a suicide kit containing sodium nitrite. Diverted from their original use as euphoriants (poppers), nitrites are now used for suicidal purposes. Specific kits have emerged on the internet. They contain sodium nitrite, metoclopramide and antacid. NaN02 is presented in the form of a powder, similar to salt, which dissolves easily in a liquid to reconstitute a toxic drink (Durão C, J Forensic Leg Med, 2020;73:101989). The lethal dose of nitrites is estimated for an adult at 2.6 g (Hwang C, Forensic Sci Med Pathol, 2021;17(3):475–80). This dose seems variable since a fatal case is described in the literature for an ingestion of 1 g (Gowans WJ, Br J Gen Pract J R Coll Gen Pract, 1990;40(340):470–1) and one non-fatal case following ingestion of 6 g (Chui JSW, Anaesthesia, 2005;60(5):496–500). In our victim's case, metoclopramide was also detected, at a concentration of 0.40 mg/L in the peripheral blood. The metoclopramide's concentration is therapeutic between 0.05 and 0.15 mg/L and toxic from 0.2 mg/L (Schulz M, Crit Care,2012;16(4):R136). Such a concentration of metoclopramide is therefore potentially toxic and can cause extrapyramidal symptoms (tremors), drowsiness, impaired consciousness, confusion, hallucinations, even cardiorespiratory arrest (Vidal) and may have contributed to death. The alarming increase in the number of cases and the access facility to these suicide kits on the internet shows that it is essential to implement measures to regulate this substance to prevent its diversion and use.

Preservative Effect of Ginger Root (Zingiber officinale R.) Extract in Refined Palm Olein Subjected to Accelerated Thermal Oxidation

Oils and fats are susceptible to the oxidation of their unsaturated fatty acids during processing, storage, or handling. Oxidation reactions lead to serious damages to oil quality that makes it to be rejected by consumers for health issues and industries that might undergo financial challenges. To limit these damages, chemically synthesized antioxidants have been added to oils and fats as preservatives. However, these were reported not to be healthy and natural substitutes extracted from plant have been the main focus of many researchers and industries these recent years. This study aimed at evaluating the preservative effect of ginger root extracts in inhibiting palm olein alteration during accelerated air-dried oven storage at 180°C. The natural antioxidants were added to palm olein at the concentrations of 200, 600, 1000, 1400, and 1800 ppm and kept in the air-dried oven for six days at 180°C (daily heating was 4 h). Butylated hydroxytoluene (BHT) was used as positive control and oil with no additive functioned as the negative one. Oil samples were collected from the oven after every 2 days for analysis. The quality parameters including the peroxide value (PV), the p-anisidine value (p-AV), the total oxidation value (TOTOX), the acid value (AV), the thiobarbituric acid value (TBA), and the iodine value (IV) were determined. The changes in the fatty acid composition of palm olein were characterized by gas chromatography coupled to a flame ionization detector (GC/FID). The ginger extract was found to be effective in delaying palm olein alteration during processing. Extract efficiency was concentration-dependent and was better than that of the control and the sample supplemented with butylated hydroxytoluene (BHT). Therefore, ginger root extract can be an ideal alternative to synthetic antioxidants used in palm olein.

Source and Distribution of Polycyclic Aromatic Hydrocarbons (PAHs) in Water from Mboppi River in Douala–Cameroon

Having a source attributed to anthropogenic activities such as incomplete combustion or pyrolysis of organic materials, polycyclic aromatic hydrocarbons are toxic organic pollutants that the ubiquity is no more to be proved. The purpose of this work is to identify and quantify the hydrocarbons pollution of the Mboppi River. Eight (8) samples of water were collected in the river during the dry and the rainy season (4samples for each season). Hydrocarbon fraction was extracted by magnetic agitation of the mixture water/hexane followed by clean-up, fractionation and subsequently, analysis using gas chromatography coupled to a Flame Ionization Detector (GC-FID). Total concentrations of polycyclic aromatic hydrocarbons in the samples were ranged between 196.3-1040.19 µg/L in the river. Polycyclic aromatic hydrocarbons with more than four rings showed the highest concentrations in the river independently from the seasonal variation while the polycyclic aromatic hydrocarbons with 2 or 3 rings were usually present in low concentrations or sometimes undetectable. From the data, it was also possible to conclude that there is predominance of petroleum sources, and essentially closed to the more industrialized areas. Mboppi River can then be considered as being among the most polycyclic aromatic hydrocarbons polluted environment in comparison with some rivers and estuaries.

Verification of Chromatographic Profile of Primary Essential Oil of Pinus sylvestris L. Combined with Chemometric Analysis.

Chromatographic profiles of primary essential oils (EO) deliver valuable authentic information about composition and compound pattern. Primary EOs obtained from Pinus sylvestris L. (PS) from different global origins were analyzed using gas chromatography coupled to a flame ionization detector (GC-FID) and identified by GC hyphenated to mass spectrometer (GC-MS). A primary EO of PS was characterized by a distinct sesquiterpene pattern followed by a diterpene profile containing diterpenoids of the labdane, pimarane or abietane type. Based on their sesquiterpene compound patterns, primary EOs of PS were separated into their geographical origin using component analysis. Furthermore, differentiation of closely related pine EOs by partial least square discriminant analysis proved the existence of a primary EO of PS. The developed and validated PLS-DA model is suitable as a screening tool to assess the correct chemotaxonomic identification of a primary pine EOs as it classified all pine EOs correctly.

Absolute quantification of terpenes in conifer-derived essential oils and their antibacterial activity

A simple, robust, and precise method for the absolute quantification of the terpenes α-pinene, camphene, β-pinene, 3-carene, limonene, bornyl acetate, β-caryophyllene, and borneol was developed using gas chromatography coupled to a flame ionization detector (GC-FID) and validated according to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use. The GC-FID method shows high accuracy (91–105%) and low imprecision (< 7.6%) for all terpenes at quality control (QC) low, medium, and high level. The curves are linear with strong correlation (R2 ≥ 0.999) for all terpenes. Additionally, the relative response factor (RRF) for each terpene is calculated. The method was validated in terms of specificity, linearity, accuracy, precision, LOD, LOQ, stability tests, and carry-over. The method was successfully applied to quantify the selected terpenes in conifer-derived essential oils (CEOs). The total amount of terpenes ranged from 6.3 to 11.8 mM. Additionally, the CEOs were screened in vitro for the antibacterial activity against E. coli and S. aureus using the broth microdilution method to determine the minimum inhibitory concentration (MIC). All the CEOs showed antibacterial activity in the concentration from 0.3 to 50 μg/mL (S. aureus) and 1.2 to 50 μg/mL (E. coli), respectively. CEO14 showed the most effective antibacterial activity of the entire tested CEOs (MIC values 0.3 μg/mL (S. aureus); 1.2 μg/mL (E. coli)). Our results suggest that the terpenoid profile should be considered for a comprehensive evaluation of the antibacterial activity, as none of the single compounds seems to be fully responsible for antibacterial activity.

An alternative approach for quantification of glyceraldehyde and dihydroxyacetone as trimethylsilyl derivatives by GC-FID

A method for quantification of glyceraldehyde (GA), dihydroxyacetone (DHA) and glycerol (GLY) by gas chromatography coupled to a flame ionization detector (GC-FID) involving one-step derivatization into trimethylsilyl ethers is presented. In pyridine, DHA and GA showed predominant peaks assigned to dimeric structures and smaller peaks corresponding to the monomers. The later were identified by GC-MS as their completely derivatized molecules and were useful for construction of calibration curves with high linear correlation. On the other hand, DHA dimers were completely dissociated in water but GA dimers remained whereas with both, intermediates peaks arose which were associated to hydrated trymethyil silyl species. A calibration approach involving the sum of areas of most relevant peaks associated to aqueous solutions of GA and DHA was developed. Replicates measurements of a problem solution were in accordance with the results obtained by a well stablished HPLC technique. The coefficient of variation was below 5% for GLY and below 12% for GA and DHA. Compared with the HPLC method, the new GC-FID method presented a similar limit of quantification in the case of GA whereas for GLY and DHA a one-order-of-magnitude increase of sensitivity was achieved. TMS derivatives of GA and DHA without prior oximation enable a useful technique to study the equilibrium of the different tautomeric forms in solution.

Mineral and phytochemical evaluation of Zea mays husk

The mineral elements and phytochemicals present in Z. mays husk an agricultural waste were identified and quantified using energy dispersive X-ray fluorescence (EDXRF) and gas chromatography coupled to a flame ionization detector (GC-FID). Calcium, sulphur and potassium which are essential mineral elements in human and animal nutrition were the most abundant with concentrations 61.74 mg/g, 38.02 mg/g and 31.14 mg/g respectively. The major phytochemicals in the ethanolic extract were phenols, flavan-3-ol, steroids, flavanones, proanthocyanins and resveratrol which were in the concentrations 12.35 mg/g, 10.74 mg/g, 10.03 mg/g, 9.19 mg/g, 5.40 mg/g and 3.36 mg/g respectively. These compounds have shown pharmacological and therapeutic activities in different studies.

Effect of Simultaneous Snail Slime-aided Degradation and Yeast Fermentation on Terpenoid Composition of Plantain Pseudostem Waste.

In this study, local sustainable enzyme sources involving excised digestive juice of African land snail and yeast were utilized to achieve the simultaneous saccharification (SSF) and fermentation (SSF) of plantain pseudostem (PPS) waste, and afterwards their effects on terpenoids using gas chromatography coupled to a flame ionization detector (GC-FID), were examined. The most abundant terpenoids were found in the order α-pinene > borneol > camphor > humulene > β-caryophellene, while the least in abundance were cis ocimene (8.78x10-6 mg/100g), and cyperene (1.81x10-5 mg/100g). The application of exclusive fermentation and SSF respectively elevated azuluene by 95.46 and 99.6%, while pinene-2-ol was elevated by 83.02 and 98.57%, respectively. Both exclusive fermentation and SSF had no effect on myrcene, cyperene, ethyl cinnamate, germacrene b, valencene, beta selinene, aromadendrene, and taraxerol, while the degree of degradation of some of the terpenoids by both processes was respectively as follows; gama muurolene (100%), β-caryophyllene (97.60 and 93.14%), α-terpinenyl acetate (91.95 and 83.16%), geranyl acetate (94.81 and 43.87%), and terpinen-4-ol (94.40 and 57.00%). The findings of this study encourage the imminent application of simultaneous saccharification and fermentation for the enhancement of bioactivities of terpenoids.

Essential oil composition in natural population of Lippia origanoides (Verbenaceae) during dry and rainy seasons

Lippia origanoides Kunth. is a medicinal shrub native to some countries in South America, Central America and the Caribbean. This study aims to investigate the chemical composition of the essential oil and the genetic diversity of a natural population of Lippia origanoides in two seasons. Leaf samples were collected from 30 individuals in the dry and rainy seasons. The essential oil was extracted into a Clevenger apparatus and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The relative quantification of thymol and carvacrol was performed by gas chromatography coupled to a flame ionization detector (GC-FID). Multivariate analysis was used to evaluate the genetic divergence between plants. Carvacrol was the major compound found in most plants for both seasons. In the rainy season, plant 15 presented thymol as the major compound, and plants 16, 27, 28 and 29 presented camphor as the major compound. In the dry season, thymol remained the main compound of plant 15 and camphor remained the main compound of plants 16, 28 and 29; however, plant 27 presented carvacrol as the main compound in this season. After carvacrol, the compounds with the highest content were γ-terpinene, p-cymene and methyl-ether-thymol. Of the 30 plants studied, only five differed in their chemical composition, showing some degree of stability in relation to the dry and rainy seasons. There was no variation in the main compounds between the two seasons, but there was chemical diversity among the main compounds. Tocher grouping revealed five distinct groups, with group 1 including most of the plants in both dry and rainy seasons, indicating that the time of year evaluated did not significantly interfere with the essential oil composition of most plants.

Changes in concentration of volatile compounds in response to defoliation of Muscat of Alexandria grapevines grown under a traditional farming system

Linalool is a monoterpene, which exhibits floral and spicy aromas as well as a variety of pharmacological effects, including antioxidant, anti-inflammatory, and cardiovascular. Wine flavor is highly dependent on the chemical compounds of berries. The objective of this study was to evaluate the concentration of volatile compounds, especially linalool, in grapes (Vitis vinifera L.) ‘Muscat of Alexandria’ grown under different cluster light exposure. Four defoliation treatments were applied at veraison, and changed the light environment at the fruit zone. Severe defoliation (T1): leaves were manually removed from the 1st to the 8th node of each shoot, partial defoliation (T2): leaves were manually removed from the 1st to the 4th, semi-shaded clusters (T3): un-trimmed vines were covered with an 80% shade netting; and (T4) control treatment with non-intervention during season 2014-2015. Free terpenes were extracted using headspace solid-phase microextraction (HS-SPME), and the concentration of volatile compounds was determined using gas chromatography coupled to a flame ionization detector (GC-FID). The study was conducted in two different locations of the Itata Valley in Chile. Linalool concentration was more prevalent in treatments with higher cluster exposure. The treatment with the highest defoliation showed a linalool concentration 40% higher than the control treatment. Higher levels of defoliation in grapevines grown under a traditional farming system result in an increased concentration of volatiles compounds, particularly monoterpenes, where Cerro Verde and Pinihue reached linalool concentrations of 19.1 and 21.7 (g L-1, respectively. These results revealed important differences in the behavior of the synthesis of linalool.

English

The Casearia species (Salicaceae) occur in the tropics and subtropics and their extracts are rich in clerodane-type diterpenes, known as casearins. According to the literature, extracts from Casearia sylvestris exhibit cytotoxic and genotoxic effects in different tumor cell lines, possibly related to the casearins. On the other hand, there are few studies related to the DNA damages of the essential oils from this species. This study is aimed at evaluating DNA damages promoted by the essential oil from leaves of C. sylvestris collected in Rio de Janeiro. The essential oil was obtained from fresh leaves (1.5 kg) by hydrodistillation for 2 h in a Clevenger-type apparatus, and analyzed both by gas chromatography coupled to a mass spectrometer (GC-MS) and gas chromatography coupled to a flame ionization detector (GC-FID). These analyses revealed a very diversified (n = 21 compounds) volatile fraction composed mainly of non-oxygenated sesquiterpenes (72.1%), and the major component was identified as &alpha;-humulene (17.8%). Genotoxicity was evaluated by the comet assay, showing DNA damages, mainly of classes 3 and 4 at 4.0 &micro;g/ml (p &lt; 0.05) according to the damage index (DI). This is the first demonstration of DNA damages in response to the essential oil of C. sylvestris. Key words: A549, &alpha;-humulene, comet assay, sesquiterpenes.

Analytical method validation of GC-FID for the simultaneous measurement of hydrocarbons (C2-C4) in their gas mixture

Se validó una cromatrografía de gases precisa, equipada con un detector de ionización de llama (GC-FID) para el análisis simultáneo de hidrocarburos ligeros (C2-C4) en su mezcla gaseosa. Los parámetros de validación se evaluaron con base en la definición de la ISO/IEC 17025, que incluye selectividad del método, precisión y repetibilidad, exactitud, linealidad, límite de detección (LOD), límite de cuantificación (LOQ) y robustez. Bajo las condiciones analíticas óptimas, el análisis de la mezcla gaseosa mostró que cada analito de interés fue separado adecuadamente con alta selectividad. Se encontró también que el método era preciso y exacto; la linealidad fue alta y con buen coeficiente de correlación lineal (R2 ≥ 0.999) para todos los analitos. Se puede concluir que el método GC-FID es confiable y apropiado para la determinación de hidrocarburos ligeros C2-C4 (incluyendo etileno, propano, propileno, isobutano y n-butano) en una mezcla gaseosa. El método validado ha sido exitosamente aplicado a la valoración de hidrocarburos ligeros C2-C4 en muestras de gas natural, mostrando alta repetibilidad con desviación estándar relativa (RDS) menor al 1% y buena selectividad sin interferencias de otros posibles componentes.

Analysis of the effect of the mitochondrial prohibitin complex, a context-dependent modulator of longevity, on the C. elegans metabolome

The mitochondrial prohibitin complex, composed of two proteins, PHB-1 and PHB-2, is a context-dependent modulator of longevity. Specifically, prohibitin deficiency shortens the lifespan of otherwise wild type worms, while it dramatically extends the lifespan under compromised metabolic conditions. This extremely intriguingly phenotype has been linked to alterations in mitochondrial function and in fat metabolism. However, the true function of the mitochondrial prohibitin complex remains elusive. Here, we used gas chromatography coupled to a flame ionization detector (GC/FID) and 1H NMR spectroscopy to gain molecular insights into the effect of prohibitin depletion on the Caenorhabditis elegans metabolome. We analysed the effect of prohibitin deficiency in two different developmental stages and under two different conditions, which result in opposing longevity phenotypes, namely wild type worms and daf-2(e1370) insulin signalling deficient mutants. Prohibitin depletion was shown to alter the fatty acid (GC/FID) and 1H NMR metabolic profiles of wild type animals both at the fourth larval stage of development (L4) and at the young adult (YA) stage, while being more pronounced at the later stage. Furthermore, wild type and the diapause mutant daf-2(e1370), either expressing or not prohibitin, were clearly distinguishable based on their metabolic profiles, revealing changes in fatty acid composition, as well as in carbohydrate and amino acid metabolism. Moreover, the metabolic data indicate that daf-2(e1370) mutants are more robust than the wild type animals to changes induced by prohibitin depletion. The impact of prohibitin depletion on the C. elegans metabolome will be discussed herein in the scope of its effect on longevity. This article is part of a Special Issue entitled: Mitochondrial Dysfunction in Aging. Guest Editor: Aleksandra Trifunovic

Dry cleaning tetrachlorethylene pollution impact on indoor air quality in Paris territory

The Central Laboratory of the Police headquarters (LCPP) is a public department which has the task among others of showing up harmful effects from exterior sources. These effects can be followed by some deteriorations of indoor air quality in close dwellings. The aim of this study is to investigate dry cleaning sources that could cause intoxications and to identify the pollution transfer mode in indoor air (air ventilation, ceiling, sewage network). The air is sampling by using sensor (passive sampling) during 7 days or by using pumps during 1 to 8 hours (active sampling) on charcoal trap and solvent desorption. The identification and quantity determination are realised by Gas Chromatography coupled to a Flame Ionization Detector (GC/FID) or to a Mass Spectrometer (GC/MS). The laboratory is accredited according to ISO 17025 for VOCs measurement on charcoal traps and the uncertainty is estimated to be around 20%. Some important levels of tetrachloroethylene were measured after more than 100 investigations in dwellings resulting from proximity complaints since 2010. The statistics results of these different studies will be discussed here. More than 80 % dwellings located above dry cleaners were polluted by tetrachloroethylene. Levels were clearly higher than the references values provided by the French high council of public health (0.25 mg/m3 for a guide value and 1.25 mg/m3 for a quick action to reduce air pollution). 50% of dwellings have tetrachlorethylene levels higher than 0.25 mg/m3. A maximum value of 120 mg/m3 have been measured in a bedroom just around a dry cleaner. Transfer modes of pollution were identified with simultaneous measures in dwelling, staircase and outdoor nearby home air inlet. The main transfer mode was carried out by ceiling or technical passage. Works of putting in conformity can be prescribed to dry cleaners. Results of studies realized before and after these works will be described. Measurements realized in dwellings above dry cleaners using substitute products of tetrachlorethylene will also been presented.

Gas chromatography – Optical fiber detector for assessment of fatty acids in urban soils

Fatty acids have been used as biomarkers of the microbial community composition of soils and they are usually separated and quantified by gas-chromatography coupled to a flame ionization detector (GC-FID). The aim of this study was to develop, validate and apply a methodology based on gas chromatography coupled to optical fiber detection (GC-OF) for screening five fatty acids used as indicators of fungal and bacterial communities in urban soils. The performance of the GC-OF methodology (optical fiber detector at 1550nm) was evaluated by comparison with the GC-FID methodology and it was found that they were comparable in terms of linear range, detection limit and analytical errors. Besides these similar analytical characteristics, the GC-OF is much cheaper than the GC-FID methodology. Different concentrations were determined for each fatty acid indicator which in turn varied significantly between the soil samples analyzed from Lisbon ornamental gardens. Additionally, the GC-OF showed a great potential as alternative for determination of eleven or more fatty acids in urban soils.

From famine plants to tasty and fragrant spices: Three Lamiaceae of general dietary relevance in traditional cuisine of Trás-os-Montes (Portugal)

The chemical composition and nutritional value of three Lamiaceae often used as spices in Portuguese traditional cuisine: Ground ivy ( Glechoma hederaceae L.), oregano ( Origanum vulgare subsp. virens (Hoffmanns. & Link) Ietswaart) and mastic thyme ( Thymus mastichina L.) were determined. Chemical composition evaluation included moisture, total fat content, crude protein, ash, carbohydrates, and nutritional value determination. The macronutrient profile revealed that these spices are rich sources of carbohydrates and that an edible portion of 100 g assures, on average, 161 Kcal. The composition in individual sugars was determined by high performance liquid chromatography coupled to a refraction index detector (HPLC/RID), being this methodology completely validated. All the compounds were separated in a period of time of 15 min; the method used proved to be sensitive, reproducible and accurate. Fructose, glucose, sucrose and raffinose were the most abundant sugars. The analysis of fatty acid composition, performed by gas chromatography coupled to a flame ionization detector (GC/FID), allowed the quantification of twenty two fatty acids. Polyunsaturated fatty acids and, in particular, α-linolenic and linoleic acids, were predominant.

Study and characterization of selected nutrients in wild mushrooms from Portugal by gas chromatography and high performance liquid chromatography

The present work aims at contributing to the documentation of the nutritional composition of wild mushrooms. Fatty acid and sugar profiles of 10 different Portuguese wild mushrooms were obtained by gas chromatography coupled to a flame ionization detector (GC/FID) and high performance liquid chromatography coupled to a refraction index detector (HPLC/RID), respectively, the latter methodology being then completely validated. The macronutrient profile in general revealed that the wild mushrooms were rich sources of protein (24.32–76.63 g/100 g) and carbohydrates (10.35–55.48 g/100 g), and had low amounts of fat (0.36–2.63 g/100 g). The highest energetic contribution was guaranteed by Hygrophoropsis aurantiaca. The analysis of fatty acid composition allowed the quantification of 25 fatty acids. Unsaturated fatty acids and, in particular, oleic and linoleic acids, were predominant (17–61% and 20–54%, respectively). In the analysis of free sugars, all the compounds were separated in a period of time of 10 min; the method used proved to be sensitive, reproducible and accurate. Arabinose (1.53–7.66 g/100 g), mannitol (0.38–18.41 g/100 g) and trehalose (0.21–18.66 g/100 g) were the most abundant sugars.