Gas Chromatography With Flame Ionization Detection Research Articles

Simultaneous determination of 16 polycyclic aromatic hydrocarbons in groundwater by GC-FID after solid-phase extraction

Groundwater contamination by polycyclic aromatic hydrocarbons (PAH) may pose a risk to human health, as these compounds are considered to be highly toxic, carcinogenic and/or mutagenic and bioaccumulative. The aim of this study was to evaluate and determine PAH levels in groundwater samples collected from tubular wells in a city of northern Brazil by gas chromatography with flame ionization detector (GC-FID) used by the population for consumption. Sample pre-treatment using solid-phase extraction cartridges was performed in order to promote an enrichment of the PAH fraction of interest and to remove interferences from the matrix to further determine PAH in samples by GC-FID. The results obtained showed that all groundwater samples studied presented PAH levels lower than maximum values allowed by MS 2914/2011 and CONAMA 396/2008. The developed procedure is characterized by low limits of detection and quantification, equal to 0.024–0.113 µg L−1 and 0.079–0.378 μg L−1, respectively, good linearity (r2 > 0.99). The recoveries obtained for 16 PAH by the addition and recovery method ranged from 85.4 to 105.7% with good precision (RSD < 5.0%). The results of this study showed that the method developed is fast, accurate and robust with high efficiency for identification and determination of 16 PAH in groundwater samples.

Chemical identification and antimicrobial potential of essential oil of Piper rivinoides kunth (BETIS-WHITE)

The family Piperaceae is known for presenting in its species flavoring, healing and antimicrobial properties among others. The objective of the present study was: to study the chemical profile of the essential oil of Piper rivinoides (EOPR); to analyze its anti-bacterial and antifungal potential, as well as to evaluate the antifungal and antibiotic-modifying capacity. The chemical constituents were identified by gas chromatography with flame ionization detector (GC-FID), allowing the identification of 7 constituents of a total of 86.99%. E-Isoelemicin was identified as the main constituent of petroleum (40.81%). Clinically relevant MIC results were obtained against fungi in which the inhibitory concentration remained <256 μg/mL, as for Candida albicans 4127 (217.6 μg/mL). The association of EOPR with an antifungal showed a high synergistic affinity against the strains of C. tropicalis 40042 and 4262. We concluded that no intrinsic EOPR activity was observed at any concentrations tested against bacteria. However, EOPR associated with Gentamicin acted synergistically against S. aureus 10 and Escherichia coli 06, but with Erythromycin there was a synergistic effect against Escherichia coli 06, and antagonism with norfloxacin.

Tramadol, Methadone and Benzodiazepines added to Alcoholic Beverages.

To search for pharmaceutical additives in illicit alcoholic beverages referred to the laboratory of Legal Medicine Organization in Iran in 2017. Hundred beverages were sampled. Ethanol content was determined by gas chromatography with flame ionization detection (GC-FID) and then a liquid-liquid extraction combined with reversed-phase high performance liquid chromatography equipped with a photodiode array detector (PAD) was employed for the qualitative analysis. The analysis was confirmed using gas chromatography coupled with mass spectroscopy (GC/MS). In 15% either one or more of the following were detected: tramadol, methadone, diazepam, oxazepam, flurazepam and alprazolam. Tramadol was found with highest frequency. The wide availability of addictive pharmaceutical is leading to fortification of alcoholic beverages on some countries. The addition of such depressant additives should be better known because of the potentially fatal consequences of the combination with ethanol, as well as the potential for adverse effects on behavior.

Analysis of Volatile Constituents of Ginkgo Leaf

Ginkgo biloba L. (Ginkgoaceae) is one of the oldest trees on earth. The medicinal use of its seeds and leaves has been a tradition for thousands of years. The standardized extract (known as EGb 761) contains several biologically active components, among them are terpenes and flavonoid glycosides that are responsible for the pharmacological activities of Ginkgonis folium. According to European Union herbal monographs (EUHM), the leaves of Ginkgo are recommended for the treatment of dementia, cerebral vascular insufficiency, and disorders of the peripheral circulation. The aim of our work was to analyze volatile constituents of Ginkgo leaf. Leaves of 3 Ginkgo trees were analyzed; 2 of which grow in the Medicinal Plants Garden (young trees A and B) and 1 at the Botanical Garden (old tree C) in Bratislava. The leaves were collected in 2014. The essential oil was isolated and quantified using hydrodistillation according to European Pharmacopoeia (Ph. Eur.) The volatile constituents of Ginkgonis folium were evaluated qualitatively and quantitatively using gas chromatography-mass spectrometry (GC-MS) and gas chromatography with flame ionization detection (GC-FID). We identified 16 constituents of the leaves of tree A, 18 in tree B, and 14 in tree C. The volatiles of the 3 trees differ in the respective amounts of monoterpenoids, hydrocarbons, fatty acids, and their methyl esters. The following constituents were identified in all of the 3 trees in largest percentage: hexahydrofarnesyl acetone (23.6%, 16.0%, and 27.7%), α-linolenic acid methyl ester (14.8%, 20.7%, and 15.1%), and pentacosane (22.2%, 22.4%, and 21.9%). Other identified compounds include the monoterpenes ( E)- α-ionone and ( E)- β-ionone.

Monitoring and assessment of formaldehyde levels in residential areas from two cities in Romania.

Formaldehyde has become a ubiquitous contaminant in the air, and people are exposed to it worldwide. However, few studies have evaluated the temporal-spatial levels/changes of formaldehyde exposure at residences, and the relationship between its outdoor and indoor levels has been rarely examined. The aim of this study was to assess community formaldehyde exposure in Sebes and Aiud, Romania to identify: (1) home environment characteristics that may play an important role in exposure; and understand: (2) if there were differences in formaldehyde levels between the two cities; (3) if there were temporal variations within each city; and (4) whether outdoor formaldehyde levels influence indoor levels. We simultaneously performed indoor and outdoor active air sampling for formaldehyde at each investigated residential location over a 3-year period and analyzed the samples by gas chromatography with flame ionization detector (GC-FID). The mean values of indoor and outdoor formaldehyde levels in both cities fell in the range 0.014-0.035 mg/m3. The correlation analysis indicated mostly positive but not significant (p > 0.05) correlations between indoor formaldehyde and microclimate factors (temperature, humidity, pressure). Notably, home insulation was found to be significantly correlated with increased indoor formaldehyde levels. There were no significant differences in mean indoor or outdoor formaldehyde levels between Sebes and Aiud over the 3-year study period. When comparing the formaldehyde levels in both cities over the 3-year period, only outdoor formaldehyde levels were significantly higher in 2016, as compared to those in 2017 and 2018.

Chemical diversity of essential oil of the Moroccan endemic Origanum grosii in natural populations and after transplantation

Oregano herbs and essential oils are considered of great interest for their medicinal virtues as well as for their culinary properties. The present investigation aims to study the chemical diversity of the essential oils (EO) of a rare Origanum species (O. grosii) endemic to the North-West of Morocco based on a large sample size (68 individual plants from 8 natural populations). Besides, 8 individual plants (genotypes) with defined EO yield and composition have been transplanted in the experimental field to show the impact of changing environmental conditions on their EO characteristics. All EOs samples were analyzed by Gas Chromatography with Flame Ionization Detector (GC-FID), Gas Chromatography/Mass Spectrometry (GC/MS) and Nuclear Magnetic Resonance (13C NMR). The EO yields of O. grosii extracted by hydrodistillation ranged from 1.71% to 2.41% with an average of 2%. The analysis showed that chemical profile of O. grosii from natural accessions is dominated by carvacrol (0.48–85.66%), p-cymene (3.01–77.49%), thymol (0–75.56%) and γ-terpinene (0–28.9%), and to a lesser extent with thymohydroquinone, thymoquinone and carvacryl methyl oxide in some individual plants with remarkable intraspecific and intrapopulation variability. The EO production of the transplanted genotypes was positively affected by the experimental field conditions. In addition, the transplantation induced changes in the chemical composition of their major components (γ-terpinene, p-cymene, carvacrol, thymol and thymoquinone) where we stated mainly an increase of γ-terpinene and carvacrol against a decrease of p-cymene. The present findings exhibit the chemical profile of O. grosii in relation with their geographical origins, besides they provide useful data concerning the impact of the culture on their EO characteristics.

Composition and Atmospheric Reactivity of Ambient Volatile Organic Compounds(VOCs)in the Urban Area of Nanjing, China

Online gas chromatography with flame ionization detection (GC-FID) systems were employed to observe 56 species of volatile organic compounds (VOCs) in the environmental atmosphere in Nanjing in 2015. The results showed that the annual volume fraction of VOCs was (17.49±11.35)×10-9. The highest concentration of VOCs was in April (22.21×10-9), and the lowest in July (12.39×10-9). Diurnal values of VOCs concentration had no obvious variations. Alkanes, alkenes, aromatics, and acetylene accounted for 56.51%, 11.06%, 24.62%, and 7.81%, respectively. Propane (15.26%), ethane (14.14%), acetylene (7.81%), toluene (6.97%), n-butane (6.23%), ethylene (5.23%), isobutane (4.34%), propylene (4.13%), isoprene (4.12%), and m/p-xylene (4.06%) were the most abundant VOCs species. The average ratio of toluene/benzene (T/B) was 2.02, indicating that the atmospheric VOCs were mainly affected by emissions of motor vehicles, especially gasoline vehicles. The average ratio of ethane/ethyne (E/E) was 2.24, showing that the plume had aged. The hydroxyl radical (·OH) loss rate(L·OH) and ozone formation potential(OFP)were applied to assess the chemical reactivity of VOCs. The atmospheric activity of VOCs was higher in the winter and spring than in the summer and autumn. Aromatics and alkenes were the most important contributors to L·OH and OFP. Their contributions to L·OH and OFP were 46.96% and 41.58%, and 33.73% and 39.86%, respectively. Propylene, ethylene, and xylene were the most active species.

Determination of Ethanol Content in Kombucha Products by Gas Chromatography with Flame Ionization Detection: A Multilaboratory Study.

Background: Kombucha is a nonalcoholic, fermented tea beverage that has recently received negative attention because of documented concentrations of ethanol in excess of allowable limits of ≥0.5% alcohol by volume (ABV). Objective: Our previously reported headspace GC with flame-ionization detection (GC-FID) method was adopted by the AOAC Expert Review Panel as First Action Official MethodSM 2016.12 in September 2016 based on published single-laboratory validation study results. This paper describes the corresponding multilaboratory study using this method to further validate its performance parameters. Methods: Four laboratories participated in the study and received practice samples, test samples, reference standards, and detailed protocols. Eight kombucha samples sent out to laboratories were randomly assigned sample numbers and were blinded in terms of content and identity. Each laboratory analyzed all samples using the GC-FID method and reported their results. Results: Cochran's C-test and single and double Grubbs' tests were used to identify and remove outliers. Horwitz ratio values for all samples were between 0.5 and 1.7. As per the Standard Method Performance Requirements (SMPRs®), all samples within the analytical range of 0.1-2.0 ABV% had RSDR values <6%. Conclusions: The results from this study demonstrate the evaluated GC-FID method meets the SMPR requirements and is fit for purpose for detecting ethanol in kombucha products. Highlights: Kombucha, a nonalcoholic, fermented beverage, has been found to contain ≥0.5% ABV. First Action Official Method 2016.12, a headspace GC-FID method for determining ethanol in kombucha, is supported by a multilaboratory study.

Analysis of major carotenoids and fatty acid composition of freshwater microalgae

Considering the nutraceutical properties, the high commercial value from pigments and essential lipids and the environmental sustainability, the purposes of this study were to assess the major carotenoids and fatty acids composition of nine microalgae species as a source of nutraceutical compounds and as fatty raw material for biodiesel production. The carotenoid and fatty acid content were analyzed by high performance liquid chromatography tandem mass spectrometry detection method with atmospheric pressure chemical ionization mode (HPLC/APCI-MS/MS) and by high resolution gas chromatography with flame ionization detector (GC-FID). For the carotenoid analysis, the developed method presented a rapid response, a good chromatographic separation, higher sensitivity and can provides more compounds information due the mass spectrum. Among the microalgae evaluated, Desmodesmus protuberans (10.3 mg g-1), Desmodesmus denticulatus var. linearis (8.43 mg g-1) and Chlamydomonas planctogloea (7.4 mg g-1) are good lutein sources. Coelastrum sphaericum (15.29 mg g-1) and Parachlorella kessleri (22.96 mg g-1) showed high astaxanthin content; the others microalgae species presents low carotenoid content. In addition, Chlorella zofingiensis provides high quantities of γ-linolenic acid (4.3%). Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels were lower than 1.1 %. Regarding for biodiesel production, the promising strains are Coelastrum sphaericum and Parachlorella kessleri.

Reaction pathways of heat-activated persulfate oxidation of naphthenic acids in the presence and absence of dissolved oxygen in water

Dissolved oxygen has been found to participate in the mineralization of naphthenic acids (NAs) by heat-activated persulfate (PS) oxidation. However, the reaction mechanisms involved needs further study. This work reports on the reaction pathways of heat (80 °C)-activated PS oxidation of model NAs in the presence and absence of molecular oxygen from the analyses of the reaction byproducts. The NAs selected include saturated and aromatic ring-bearing structures. The analyses were performed by gas chromatography with mass spectrometer (GC–MS), liquid chromatography with quadrupole time-of-flight mass spectrometer (LC-QTOF-MS), gas chromatography with flame ionization detector (GC-FID) and ion chromatography (IC). The results suggest that decarboxylation of NAs is the initial step of PS-oxidation under air and inert atmosphere. Cyclohexanone-like compounds are one kinds of the main intermediates, indicating the occurrence of oxygenation upon the reaction. The formation of those compounds relies on the dissolved oxygen since it was significantly hindered in inert atmosphere. This hindering effect was less significant in the case of aromatic ring-bearing NAs than for the saturated ones. Meanwhile, condensation byproducts were formed in the absence of oxygen. The corresponding degradation and ring-opening mechanisms were postulated on the basis of analytical results.

Comprehensive certification of a testosterone calibration standard facilitating the investigation of charged aerosol detection for the quantification of impurities of related structure

Testosterone, an analyte of interest to medical testing laboratories, was purity assigned using a mass balance approach, to afford a certified value of 986 ± 3 mg g−1 with established metrological traceability to the SI unit for mass (kg). The gas chromatography with flame ionisation detection (GC-FID) analysis identified the thermal degradation of testosterone as a source of bias, and confirmed the other four impurities to be steroids of closely related structure through co-elution studies. Combined with measures of water, solvent and non-volatile residue the total purity was in agreement with that determined by the complementary quantitative NMR spectroscopy, providing a high level of confidence that the certified value was bias free. This sample was then used to investigate the applicability of charged aerosol detection to the assessment of high accuracy, low uncertainty organic purity determination of steroids. The relative peak areas of testosterone and impurities varied depending on the concentration of the test solution, precluding the direct conversion of peak areas to an accurate realization of the relative mass fraction. One impurity, androst-4,6-diene-17β-ol-3-one, being overestimated by 155% compared to the GC-FID result. Charged aerosol detection (CAD) calibration curves established for testosterone and each impurity confirmed the detector response to vary by up to 30% at low levels (0–20 μg g−1), thereby challenging the view that the CAD response is independent of structure. Despite this, using the calibration curve of testosterone to quantify each impurity delivered a reasonable estimate of organic purity. The variations in detector response for each analyte were used to assign a conservative uncertainty to the calculated value, offering a way forward when CAD is to be used for a less well defined material.Finally, the candidate material demonstrated a propensity to absorb water, highlighting the need to monitor water absorption during on-going stability trials.

Chemical Composition, in vitro Trypanocidal and Antibacterial Activities of the Essential Oil from the Dried Leaves of Eugenia dysenterica DC from Brazil

Natural products are a very important source of bio-molecules for drug to treat infectious diseases. The essential oil of Eugenia dysenterica DC. dried leaves (Ed-EO), of the Myrtaceae family, was analyzed by gas chromatography with flame ionization detector (GC/FID) and by mass spectrometry (GC/MS) in order to identify their volatile components. A total of 24 compounds were identified from Ed-EO. The major compounds found in Ed-EO were limonene (16.0 %), caryophyllene oxide (15.0 %), citral (9.0 %), trans-caryophyllene (8.0 %), and 1,8-cineole (7.3 %). The in vitro biological activities of Ed-EO were investigated against trypomastigote forms of Trypanosoma cruzi and bacteria of the genus Streptococcus. Our results demonstrated that Ed-EO, tested against T. cruzi, affected trypomastigote growth in a dose-dependent manner. The IC50 of Ed-EO was 9.5 μg/mL, while the IC50 of benznidazole (positive control) was 9.8 μg/mL, revealing remarkable trypanocidal action. The minimum inhibitory concentrations (MICs) were determined by the broth dilution method in 96-well microplates. The Ed-EO displayed moderate antibacterial activity against Streptococcus mitis (MIC = 250 μg/mL), S. sanguinis (MIC = 200 μg/mL), S. sobrinus (MIC = 400 μg/mL), and S. salivarius (MIC = 400 μg/mL), and strong activity against S. mutans (MIC = 31.2 μg/mL). These results suggest that the oil of E. dysenterica dried leaves could be tested in future studies for the treatment of Chagas disease and dental caries.

Determination of PAHs in Selected Sampling Location in Langkawi Island, Malaysia

Surface seawater samples were collected from five selected sampling locations in the Langkawi Island during the northeast monsoon season in March 2013. Water samples were extracted by using two different solid phase microextraction (SPME) fibers followed by gas chromatography with flame ionization detector (GC-FID) analysis. Naphthalene compound (2-rings) indicated no significant different (p>0.05) extracted by using 65 μm-PDMS-DVB and anthracene compound (3-rings) extracted by using 85 μm-PA fibers. The average spike recovery for PAHs ranged from 64.8 to 94.0%. Total PAH concentration (Σ3 PAHs) ranged from 10.79 μg/mL to 369.28 μg/mL which exceed the maximum admissible concentration of PAHs (0.0002 μg/mL) for the water standard of European Union. The result revealed that the surface seawater around the Langkawi Island was highly contaminated by PAHs. The high concentration of PAHs may be due to extensive port associated activities.

Nutritional and Microbiological Composition of Serra Estrela Cheese: A Paradigm to Overcome

Background: Milk and dairy products are an excellent source of well-balanced nutrients with multiple uses as a snack, dessert or food ingredient. Serra Estrela cheese, a traditional variety manufactured in the centre region of Portugal, is part of the mankind´s ancient cultural heritage, made from raw sheep milk it is assumed as an iconic gourmet cheese, when compared with other Portuguese cheeses. This work intended to monitor the manufacturing process along the period of production, to evaluate the factors that are decisive for the reproducibility of Serra Estrela cheese in geographical and temporal terms, as well as to achieve the knowledge of the Serra Estrela cheese lipid nutritional characteristics. Methods: Twenty-four Serra Estrela cheese samples originating from representative cheese producers of the region were analysed for their nutritional characteristics, such as moisture, fat, protein and salt, using the FT-NIR (fourier-transform near infrared spectroscopy) technique as an expeditious method. A gas chromatography with flame ionization detection (GC-FID) was used to perform the lipid fraction study. Microbiological analyses were performed for Escherichia coli and coagulase-positive Staphylococcus. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS version 23.0). The level of significance was accessed by Tukey’s test considering p-value < 0.05 to be significant. Results: In the cheeses studied, the moisture varied from 46 % to 52 %, the butyric content from 19 to 30 %, the protein content between 19 and 24 % and the salt from 0.9 to 1.8 %. The determinations of Escherichia coli and coagulase-positive Staphylococcus in some Serra Estrela cheeses exceeded the maximum allowed values per law in Portugal. Regarding to the fatty acids profile, there was no obvious tendency observed, but was found a significative amount of short and medium chain saturated fatty acids, as well as polyunsaturated fatty acids. Conclusion: Considering that year 2017 was considered an exceptional year, both in terms of the severe drought and the fires that devastated the region, with repercussions on health and animal production, it is reasonable that some cheeses exceeded the maximum permissible levels of microorganisms. Although there are significantly differences between the total fat and protein content of Serra Estrela cheeses from different producers, relatively to polyunsaturated, ω-3 and ω-6 fatty acids fractions, all cheese producers are very homogeneous. This work was extremely important for an initial evaluation of the Portuguese Serra Estrela cheese production in 17/18 and for the design of future experimental work.

Investigating the Relationship between Antioxidants and Fatty Acid Degradation Using a Combination Approach of GC-FID and Square-Wave Voltammetry.

Analytical methodology for direct investigation of antioxidant systems continues to be a pressing research area. Consumer demand for natural products requires an increase in natural antioxidants; thus, fast, high-throughput, and cost-effective screening methods are in demand. In this study, square-wave voltammetry and gas chromatography with flame ionization detection (GC-FID) were used in conjunction to monitor antioxidant and fatty acid degradation, respectively, during the accelerated degradation of an omega-3 fatty acid sample. Butylated hydroxytoluene, sesamol, and rosemary extract were investigated as antioxidants. It was determined that voltammetry could be used to monitor the reduction in oxidation current, which provides a direct assessment method for the reduction of native antioxidant concentration throughout the accelerated degradation. Furthermore, results showed that voltammetry could be used to monitor fatty acid degradation similarly to the fatty acid methyl ester analysis routinely performed using gas chromatography separation. Both voltammetry and GC-FID methods reached similar conclusions about antioxidant quality and efficiency for omega-3 fatty acid protection.

Lipid Profile Determination by Direct Infusion ESI-MS and Fatty Acid Composition by GC-FID in Human Milk Pools by Folch and Creamatocrit Methods

Human milk (HM) is extremely important to the baby, containing a varied and balanced range of nutrients fundamental to the ideal development of the newborn. Among these nutrients, HM lipids provide 40-60% of the energy. In HM banks, the creamatocrit method is employed as a quick and solvent-free tool, however, since Folch methodology is considered reference for lipid extraction, this study compared the fatty acid (FA) composition and the lipid profile by gas chromatography with flame ionization detector (GC-FID) and direct infusion by electrospray ionization mass spectrometry (DI-ESI-MS) in pools of different HM phases, obtained from Folch and creamatocrit methods, in order to elucidate which method provides better information about HM lipids. Lipid compositon results by Folch were superior to the results obtained by creamatocrit in HM pools investigated. It means, the lipid profiles of all HM pools were more intense, and the number of FA identified by Folch was also higher in comparison to the creamatocrit method (21 and 6 FAs, respectively). GC-FID analysis in combination with principal component analysis (PCA) divided the methods, confirming a greater contribution of the Folch method. Therefore, Folch methodology revealed an effective lipid extraction in comparison to creamatocrit method.

Effect of Benzene Exposure on the Urinary Biomarkers of Nucleic Acid Oxidation in Two Cohorts of Gasoline Pump Attendants.

(1) Background: The oxidized guanine derivatives excreted into urine, products of DNA and RNA oxidation and repair, are used as biomarkers of oxidative damage in humans. This study aims to evaluate oxidative damage in gasoline pump attendants occupationally exposed to benzene. Benzene is contained in the gasoline but it is also produced from traffic and from smoking. (2) Methods: Twenty-nine gasoline pump attendants from two major cities of Saudi Arabia and 102 from Italy were studied for urinary 8-oxo-7,8-dihydroguanine (8-oxoGua), 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo), 8-oxo-7,8-dihydroguanosine (8-oxoGuo), and S-phenyl-mercapturic acid (SPMA) for benzene exposure and urinary cotinine for smoking status assessment by liquid chromatography-tandem mass spectrometry. Airborne benzene was also assessed in the Italian group by gas-chromatography with flame ionization detector (GC-FID). (3) Results: The results suggest that high levels of benzene exposure can cause an accumulation of SPMA and bring about the formation of the oxidation biomarkers studied to saturation. At low exposure levels, SPMA and oxidation biomarker levels were correlated among them and were associated with the smoking habit. (4) Conclusions: The study confirms the association between benzene exposure and the excretion of nucleic acid oxidation biomarkers and enhances the importance of measuring the smoking habit, as it can significantly influence oxidative damage, especially when the exposure levels are low.

Matrix Extension with Fitness for Purpose and Stability Assessment of DHA and Additional Fatty Acids in Individual Whole Chicken Eggs

The consumption of long chain polyunsaturated fatty acids (LC-PUFA) is associated with several human health benefits. Most notable of these LC-PUFA is docosahexaenoic acid (DHA C22:6) whose inclusion is considered essential for optimum human health. Biofortification of common foods such as eggs with DHA has emerged as a specific approach to increase the intake of DHA in human populations. This can be achieved by supplementing poultry rations with feeds like microalgae or fish oil that are rich in DHA, which results in an increased uptake in the egg. Gas chromatography with flame ionization detection (GC-FID) is the method of choice when analyzing food such as eggs for DHA and other fatty acids. For regulatory studies it is desirable to demonstrate that the method is specifically suitable for the analysis of DHA and fatty acids in eggs. The purpose of this paper is to further extend the scope of the AOAC 996.06 methodology examined in the paper by Dillon et al., and to demonstrate the fitness for purpose of the method by examining specific validation parameters. It is a further objective to investigate the stability of DHA and other fatty acids of short and long timepoints. A validation of the method for the determination of DHA and three other fatty acids in eggs is thus presented.

Validation and application of a chromatographic method for evaluation of commercial vegetable oils possibly adulterated

A method of separation, identification and quantification of fatty acid methyl esters (FAMEs) was developed by gas chromatography with flame ionization detector (GC-FID) using a basic transesterification. In this sense, there were analyzed FAMEs in commercial samples of vegetable oils from soybean and olive oil. The referred method was linear (r&gt;0.99), accurate and precise for palmitic (C16:0), linoleic (C18:2), oleic (C18:2), linolenic (C18:3) and stearic (C18:0) acids. The limits of detection (LOD) and quantification (LOQ) were from 0.03 to 0.31 and 0.08 to 0.94 mg.mL-1 for the five fatty acids, respectively. The results demonstrated that the unsaturated fatty acids were the most abundant for the two samples, being the oleic acid (C18:1) the major in three brands of olive oil (D, E and F), and the linoleic acid (C18:2) the most abundant in soybean oil and the other brands of olive oil (G, H and I), suggesting a possible adulteration in these brands. The proposed method could be considered a tool for the investigation of adulteration in commercial vegetable oils for guaranteed reliability in the results to be comparable with correlated legislations.

Biodiesel synthesis from eucalyptus oil by utilizing waste egg shell derived calcium based metal oxide catalyst

Heterogeneous catalysts have emerged as potential alternatives to their homogenous counterparts, since they could successfully overcome the shortcomings encountered in homogenous catalytic trans-esterification of tri-acyl glycerides. In the present study, application of pure as well as doped CaO derived from waste chicken egg shells was studied for conversion of oil into biodiesel. Waste eggshells were calcined at 900 °C to get CaO which was then incorporated into transition metals by incipient wet impregnation method. The catalyst prepared has been characterized by Scanning electron microscope (SEM), Thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) techniques. The basicity and surface area of catalysts were ascertained in order to figure out the catalytic activity. The conversion of oil to Fatty acid methyl esters (FAME) has been confirmed by Thin-layer chromatography (TLC) and the percentage yield of eucalyptus biodiesel was verified by Gas chromatography with Flame ionization detector (GC-FID). The catalytic property of these mixed metal oxides has been studied in trans-esterification of Eucalyptus Oil. Zn-CaO (waste egg shell) was observed to be the most promising catalyst providing with appreciable yield of bio-diesel (FAME) among all the three catalysts. Transesterification was carried out at different process variables to optimize the best reaction conditions. Employing waste chicken egg shell derived CaO doped with transition metals (Zn, Cu) as catalyst puts forward the economic and efficient scheme for trans-esterification of Eucalyptus oil for biodiesel generation.