Gas Chromatography With A Flame Ionization Detector Research Articles

Chemical Investigation on the Volatile Part of the CO2 Supercritical Fluid Extract of Infected Aquilaria sinensis (Chinese Agarwood).

This work is focused on the characterization of the composition of a CO2 supercritical fluid extract of Aquilaria sinensis (Chinese agarwood) collected in the Dongguan area (China) and infected by mechanical methods. The constituents of this extract were analyzed by gas chromatography-mass spectrometry (GC-MS) and quantified accurately by gas chromatography with a flame ionization detector (GC-FID), using an internal reference and predicted response factors. Since a significant number of components of this extract remained non-identified after the initial GC-MS analysis of the whole extract, its fractionation by chromatography on silica gel helped to characterize several additional constituents by isolation and structural analysis by NMR spectroscopy. The main components are the classical agarwood chromones (Flindersia chromone and its mono-, di-, and trimethoxylated analogues (respectively, 11.01% and 0.11-4.02%) along with sesquiterpenic constituents typically found in agarwood essential oils, like baimuxinal (1.90%) and kusunol (1.24%), as well as less common selinane dialdehydes (1.58-2.27%) recently described in the literature. Moreover, the structure and stereochemistry of a new sesquiterpenic alcohol, 14β,15β-dimethyl-7αH-eremophila-9,11-dien-8β-ol (0.67%), was determined unambiguously by the combination of structural analysis (NMR, MS), hemisynthesis, and total synthesis, leading to dihydrokaranone and a neopetasane epimer.

Source Apportionment and Health Risk of Some Organic Contaminants in Water and Suspended Particulate Matter from Imo River, Nigeria

The objective of this study was to provide the source identification and assessment of potential health associated with some organic contaminant detected in water and suspended particle matter (SPM) from the Imo River, Nigeria using gas chromatography with a flame ionization detector (GC/FID) after 1:1 ratio solvent mixture (n-hexane and dichloromethane) extraction. The findings on SPM revealed the values; pH (5.42±0.097-5.567±0.057), conductivity (74.58±5.390-87.6±0.9 uS/cm), and total organic carbon (TOC) (3.626±0.366-6.143±0.176), and surface water; pH (6.077±0.049-6.46±0.52), conductivity (49.03±1.430- 58.12±0.553 uS/cm). The total concentrations of both low and high molecular PAHs in SPM recorded at stations1-3 were 4.384 mg/kg, 16.87 mg/kg, and (22.69 mg/kg); surface water 2.329 mg/L, 7.428 mg/L and 6.657 mg/L. The source apportionment of PAHs in SPM and surface water via molecular diagnostic ratios identified both petrogenic source (crude oil, petroleum spillages, and seepages) and pyrogenic sources (combustion of grass, wood, coal, and gas flaring). A further analysis with Principal Component Analysis (PCA) revealed two principal components, with 65.568% for component 1 and 34.432% for component 2 for SPM, and 62.80% for principal components and 37.2% for principal component 2 for surface water. The correlation analysis of PAHs affirmed common sources such as petrogenic and pyrogenic origins. The toxic equivalent factor of total benzo(a)pyrene for 6 ∑PAHs in SPM was recorded as 3.693 mg/kg, 1.605 mg/kg, and 0.453 mg/kg; surface water was recorded as 0.823 mg/L, 1.858 mg/L, and 0.353 mg/L, while the mutagenic equivalency quantities of SPM were recorded as 3.693mg/kg, 1.146 mg/kg, and 0.316 mg/kg; surface water 0.739 mg/L, 0.938, and 0.577 for stations 1-3. The effect of carcinogenic PAHs in SPM was higher in adults than in children, with regards to ILCR analysis. Users of Imo Rivers should be guided on the exposure of SPM and surface water since the toxic, mutagenic, and cancer risk levels of the river are above the permissible limit in some stations.

Investigating the Effectiveness of Different Porous Nanoparticles as Drug Carriers for Retaining the Photostability of Pinosylvin Derivative.

Pinosylvin monomethyl ether (PsMME) is a natural compound known for its valuable bioactive properties, including antioxidant and anti-inflammatory effects. However, PsMME's susceptibility to photodegradation upon exposure to ultraviolet (UV) radiation poses a significant limitation to its applications in the pharmaceutical field. This study, for the first time, introduces a strategy to enhance the photostability of PsMME by employing various nanoformulations. We utilized mesoporous silica nanoparticles (MSNs) coated with polydopamine via a poly(ethylene imine) layer (PDA-PEI-MSNs), thermally carbonized porous silicon nanoparticles (TCPSi), and pure mesoporous polydopamine nanoparticles (MPDA). All these nanocarriers exhibit unique characteristics, including the potential for shielding the drug from UV light, which makes them promising for enhancing the photostability of loaded drugs. Here, these three nanoparticles were synthesized and their morphological and physicochemical properties, including size and ζ-potential, were characterized. They were subsequently loaded with PsMME, and the release profiles and kinetics of all three nanoformulations were determined. To assess their photoprotection ability, we employed gas chromatography with a flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS) to assess the recovery percentage of loaded PsMME before and after UV exposure for each nanoformulation. Our findings reveal that MPDA exhibits the highest protection ability, with a remarkable 90% protection against UV light on average. This positions MPDA as an ideal carrier for PsMME, and by extension, potentially for other photolabile drugs as well. As a final confirmation of its suitability as a drug nanocarrier, we conducted cytotoxicity evaluations of PsMME-loaded MPDA, demonstrating dose-dependent drug toxicity for this formulation.

Online quantification of nicotine in e-cigarette aerosols by vacuum ultraviolet photoionization mass spectrometry.

The growing popularity of e-cigarettes and the associated risks of nicotine addiction present a new challenge to global public health security. Measuring the nicotine levels in e-cigarette aerosols is essential to assess the safety of e-cigarettes. In this study, a rapid in situ method was developed for online quantification of nicotine in e-cigarette aerosols by using a homemade vacuum ultraviolet photoionization aerosol mass spectrometer (VUV-AMS). E-cigarette liquids with different nicotine concentrations were prepared to generate aerosols containing different levels of nicotine, which were employed as the calibration sources for nicotine quantification by VUV-AMS. The results showed that the mass concentration of nicotine in e-cigarette aerosols has a good linear relationship with its signal intensity in the mass spectrum, and the limits of detection and quantitation of nicotine by VUV-AMS were found to be 2.0 and 6.2 μg per puff respectively. Then the online method was utilized to measure five commercial e-cigarettes, and their nicotine yields were determined to be between 31 and 188 μg per puff with the nicotine fluxes from 7.7 to 70 μg s-1, agreeing with the results of the gas chromatography with a flame ionization detector (GC-FID). This study demonstrated the feasibility and advantages of VUV-AMS for quick quantification of nicotine in e-cigarette aerosols within seconds.

New biological monitoring method for 1-Naphthol and 2-Naphthol based on stir bar sportive dispersive micro extraction strategy using magnetic ionic liquid

Naphthalene is one of the few volatile bicyclic aromatic hydrocarbons and a white crystalline solid that can sublimate at room temperature. Since 2000, according to the results of animal studies on the carcinogenic effects of naphthalene, this substance has been recognized as a major problem for the environment and industrial environments. Exposure to naphthalene leads to kidney toxicity, hemolytic anemia and other health problems in the human body. The International Agency for Cancer has placed naphthalene in group 2B (probably carcinogenic to humans). 1- naphthol and 2- naphthol are biological urinary indicators of human exposure to naphthalene in work environments. For the first time in this research, the concentration of 1-naphthol and 2-naphthol in urine, which serves as an indicator of naphthalene exposure, was performed through a method known as magnetic ionic liquids-based disperse liquid–liquid microextraction (MIL-DLLME). Subsequently, the samples were analyzed using gas chromatography with a flame ionization detector (GC-FID). Additionally, the factors that influence the extraction of this metabolite, such as the quantity of extracting solvent, speed of mixing, proportion of salt added, duration of mixing, and pH value, were determined using both a two-level factorial test design and a central composite design. Calibration curves were developed under optimal conditions, and the validity of the developed microextraction method was studied with different statistical methods and the analysis of real samples. A strong linear correlation between the subpeak level and the corresponding concentrations was observed in the range of 0.5–0.002 μg/ml for 1-naphthol and 2.00–0.001 µg mL-1for 2-naphthol. In addition, the detection limit and quantitative detection limit for 1-naphthol were 0.0006 µg mL−1, 0.002 µg mL−1, and 0.0003 µg mL−1, 0.001 µg mL-1for 2-naphthol respectively. The MIL-DLLME extraction method can be regarded as an environmentally friendly microextraction technique since it eliminates the need for dispersing solvents and toxic organic solvents as extractants. Results showed that the proposed technique can be applied for biological monitoring of the biomarkers of naphthalene in the exposed workers during occupational or environmental assessments.

VALIDATION OF HEADSPACE SOLID-PHASE MICROEXTRACTION WITH GAS CHROMATOGRAPHY-FLAME IONISATION DETECTOR METHOD FOR ALCOHOL ANALYSIS ON GASTRIC FLUID

Identifying the concentration of alcohol compounds in postmortem analysis of biological fluids can help the investigation, just as postmortem analysis of gastric juices can reveal the concentrations of alcohol consumed. However, an efficient and effective combination of extraction and measurement methods is required when looking at complex postmortem samples. Therefore, a headspace-solid phase microextraction (HS-SPME) method was developed using gas chromatography with a flame ionization detector (GC-FID) to identify postmortem alcohol concentrations. This present study optimizes and validates an effective and efficient method for postmortem alcohol extraction and quantification in gastric fluid. The optimal conditions for HS-SPME extraction using 65μm Polydimethy lsiloxane Divinyl benzene (PDMS/DVB) fiber for analyte isolation were 15 minutes. at 60°C and an exposure time of 1 minute. The validation investigation shows that the suggested approach satisfies the criteria for linearity, precision, accuracy, LOD, and LOQ for postmortem measurement of alcohol in gastric fluid.

Determination of Fatty Acid Profile in Processed Fish and Shellfish Foods.

Seafood products are a crucial dietary source of n-3 polyunsaturated fatty acids (n-3 PUFA), which are essential for human health. However, the presence of these n-3 PUFA may be subject to changes related to different processing methods. The aim of this study was to determine the fatty acid composition, focusing on n-3 PUFA, in different processed fish and shellfish products of both EU and non-EU origin. The products were purchased from supermarkets and ethnic food shops in Messina (Italy). Gas chromatography with a flame-ionization detector (GC-FID) was used for analysis. Based on the fatty acid profile, the atherogenicity index (AI), thrombogenicity index (TI), and flesh lipid quality index (FLQ) were determined: 0.13-1.04 (AI), 0.19-0.89 (TI), and 0.41-29.90 (FLQ). The percentages of saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) fatty acids fell within the following ranges: 13.55-50.48%, 18.91-65.58%, and 13.84-52.73%, respectively. Considering that all samples showed low AI and TI indices and that all processed fish products proved to be a good source of beneficial PUFAs, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), their consumption is recommended for humans.

Exposure to anesthetic gases in the operating rooms and assessment of non-carcinogenic risk among health care workers

Health care workers employed operating room in hospital and health centers are unavoidably exposed to inhaling toxic gases, including isoflurane and sevoflurane. Chronic contact with these gases increases the risk of spontaneous abortion, congenital anomalies and cancers. Risk assessment is an important tool in predicting the possible risk to personnel's health. Therefore, this study was conducted with the aim of determining the concentration of isoflurane and sevoflurane gas in the air of the operating room and estimating the non-carcinogenic risk caused by them. In this descriptive-cross-sectional study, according to the occupational method (OSHA 103), 23 samples (isoflurane and sevoflurane) were collected in the air of operating rooms of four selected hospitals in Ahvaz city by using SKC sampling pumps and sorbent tube (Anasorb 747). The samples were determined by used to gas chromatography with a flame ionization detector (GC/FID). Statistical analysis, including the Kruskal-Wallis test, was used to compare the average concentration of anesthetic gases, and the one-sample t-test was used to compare the average with the standard level. In all analyses, the significance level was 0.05, which was performed by SPSS version 22 software. Result of this study showed that the average concentration of isoflurane in private and general hospitals were 23.636 and 17.575 ppm, respectively. Also, the average level of sevoflurane were 1.58 and 7.804 ppm. According to the results the mean amount of anesthetic gases was within the range recommended by Iran's Occupational and Environmental Health Center and the permissible threshold limit provided by ACGIH. In addition, non-cancer risks from occupational exposure to isoflurane and sevoflurane in selected private and general hospitals were acceptable (HQ < 1). Although the results show that overall occupational exposure to anesthetic gases is less than acceptable but long-term exposure to anesthetic gases may endanger the health of operating room staffs. Therefore, it is recommended to implement some technical controls, including regular inspection of ventilation systems, the use of advanced ventilation systems with high cleaning power, continuous control of anesthesia devices in terms of leakage, and periodic training of related staff.

A chemical study of yoghurt produced under isostatic pressure during storage

Yoghurt fermented under sub-lethal high pressure (10, 20, 30 and 40 MPa at 43 °C), and afterward placed under refrigeration (4 °C for 23 days) was studied and compared with yoghurt fermented at atmospheric pressure (0.1 MPa). For a deeper analysis, metabolite fingerprinting by nuclear magnetic resonance (NMR), sugars and organic acids assessment by high performance liquid chromatography (HPLC), total fatty acids (TFA) determination and quantification by gas chromatography with a flame ionization detector (GC-FID) were performed. Metabolomic analyses revealed that only 2,3-butanediol, acetoin, diacetyl and formate vary with the increase of pressure and probable relation with pressure influenced diacetyl reductase, acetoin reductase and acetolactate decarboxylase. Yoghurts fermented at 40 MPa had the lowest content in lactose (39.7 % of total sugar reduction) and the less content in TFA (56.1 %). Further research is of interest to understand more about fermentation processes under sub-lethal high pressure.

Changes in fatty acids during storage of artisanal-processed freshwater sardines (Rastrineobola argentea).

For ages, indigenous small fish species have been important in food and nutritional security of poor communities in low income countries. Freshwater fish, in particular fatty fish species are attracting a great attention because they are good sources of health promoting long chain omega-3 fatty acids. Docosahexaenoic acid (DHA, C22:6n-3), Docosapentaenoic acid (DPA, C22:5n-3) and eicosapentaenoic acid (EPA, C20:5n-3) are the main omega-3 PUFAs known to confer health benefits in humans if consumed in required amounts. While nutritionally valued, omega-3 PUFAs in fish are susceptible to oxidative damage during processing, transportation and subsequent storage. Lake Victoria sardines (Rastrineobola argentea), are rich source of chemically unstable omega-3 fatty acids DHA, DPA and EPA. Traditionally, sardines are preserved by sun drying, deep frying and smoking. Sardine products are transported, stored and marketed at ambient temperatures. Generally, uncontrolled and higher temperatures are known to increase vulnerability of polyunsaturated fatty acids to oxidation which in turn results into loss of nutritional and sensory qualities. This study investigated changes of fat acids in sun dried, deep fried and smoked sardines during storage. Lipolysis and the progressive hydroperoxides formation were monitored by free fatty acids (FFAs) and peroxide value (PV) respectively. None volatile secondary products of lipid oxidation were measured by thiobabituric acid reactive substances (TBARS). Fatty acids were analyzed by gas chromatography with a flameionization detector (GC-FID). Deep fried sardines maintained the lowest and apparently stable PV, TBARS and FFAs. Proportions of saturated fatty acids and polyunsaturated fatty acids decreased with time while that of monounsaturated fatty acids increased. Omega-3 fatty acids EPA, DPA and DHA decreased with increase in storage time. In 21 days of storage, DHA was oxidized beyond detectable levels in all sardine products. Gradual increase in FFAs in sun dried sardines was suggestive of lipid hydrolysis induced by enzymes.

Characterization of polyunsaturated fatty acids and antioxidant activity of Vitis vinifera L. (grape) seeds from the Ica Valley, Peru

Context: In the Valley of Ica-Peru, the seeds of the fruit of Vitis vinifera L. (grape) are residues from the Pisco Industry, and due to their bioactive compounds, they can represent a new economic and sustainable activity for the population of the mentioned Valley. Aims: To characterize polyunsaturated fatty acids from the seeds of the fruit of Vitis vinifera L. (grape) from the Ica Valley, Peru and determine the antioxidant activity in vitro. Methods: The oil from five grape varieties (Quebranta, Moscatel, Torontel, Mollar, and Italia) was obtained by ethereal extraction with ultrasound. The profile of fatty acids was characterized by gas chromatography with a flame ionization detector (GC-FID). The total polyphenolic content was determined by the Folin-Ciocalteu method and antioxidant activity by two in vitro methods. Results: The values obtained from the 5 grape varieties are presented in a range: total polyphenolic content (TPC: 0.59-154 mg GAE/g); linoleic acid content (69.90-71.87%), oleic acid (18.35-19.90%) and others in a lower percentage (p&gt;0.05). Antioxidant activity: DPPH IC50 38.30-48.43 µL; FRAP 0.49-0.77 μg TEAC/g. TPC/DPPH and TPC/FRAP were significantly different (p&lt;0.05), except for the Mollar TPC/FRAP variety (p&gt;0.05). Conclusions: The oils from the seeds of the Vitis vinifera fruit (grapes) that are residues from the production of Pisco present physicochemical characteristics of oils of high nutritional value with a predominance of polyunsaturated fatty acids and potential antioxidant activity.

Analytical Method for Residual Monomer Ethyl Acrylate Determination in Commercial Latex Resin using Gas Chromatography with Flame Ionization Detection

Latex (acrylic resin) produced by emulsion polymerization usually contains variable amounts of residual volatiles (free monomers). Depending on the chemical nature of the monomer, even if these compounds are present in smaller quantities than other volatiles, they can make the latex exude a strong odor and offer toxicity, as with ethyl acrylate, which may make it unfeasible for the consumer to apply the latex. In the present study, a quantitative chromatographic method using gas chromatography with a flame ionization detector (GC-FID) for industrial laboratory determination was investigated. Free ethyl acrylate monomer at a concentration level of 0.010% w/w in a resin-type latex was determined. This method showed selectivity for ethyl acrylate versus other volatiles in the sample, linearity with a coefficient of determination greater than 0.99, limits of detection and quantification of 0.001 and 0.003% w/w, respectively, accuracy and precision with recoveries above 85% and coefficients of variation below 10%. The robustness parameter demonstrated with a Pareto chart shows that the chromatographic parameters of the split ratio, injection volume and temperature impact the method performance.

Determination of Polychlorinated Biphenyls in Water Samples Using a Needle Trap Device Combined with Gas Chromatography

In this study, a fiber-packed needle trap device (NTD) was developed by packing heat-resistant fibers with a polyethylene glycol sol-gel coating into a 21-gauge, stainless steel needle. The polyethylene glycol sol-gel coating has numerous advantages, including uniform roughness and a large specific surface area. The prepared NTD was used for headspace extraction of five polychlorinated biphenyls (PCBs) in water samples, determined by gas chromatography with a flame ionization detector (GC-FID). The main experimental parameters, including the extraction and desorption conditions, ionic strength, and fiber bundles, were investigated to improve the extraction efficiency. After optimization, satisfactory linearity (r &gt; 0.99) in the concentration range of 0.02–500 μg/L was obtained, and the enrichment factor of NTD for the five PCBs was between 1150 and 9537 times. The limit of detection (S/N = 3) of five PCBs were measured in ranges of 0.0021–0.01 μg/L. Furthermore, the fiber-packed NTD has excellent durability, and can be reused for 60 cycles. After being stored at room temperature for three days, the storage ability of the NTD had a loss of PCBs less than 10%, and the relative standard deviation (RSD) was less than 10%. When analyzing the PCBs in real water samples, good accuracies (spiked recoveries were in the range of 92.19–98.56%) and precision (the RSD was lower than 12.8%) was obtained.

Pooled Urine Analysis at a Belgian Music Festival: Trends in Alcohol Consumption and Recreational Drug Use.

Recreational drug use has become more and more accepted in society. Availability and purity are rising and new psychoactive substances (NPS) are popping up.The aim of this study was to provide objective data on illicit drug use at a Belgian festival in order to report on arising trends. This may provide additional information to help develop preventive strategies. A cross-sectional study took place during a music festival in the summer of 2019, where 43 samples of pooled urine were collected at four different locations and at different moments of the day. Analysis was performed using gas chromatography with a flame ionization detector (GC-FID) to determine ethanol concentrations. Drugs of abuse were quantified using liquid chromatography-tandem mass spectrometry. A qualitative analysis was performed using high-resolution mass spectrometry. Median ethanol concentration was 0.88g/L. Cocaine, 3,4-methylenedioxymethamphetamine (MDMA), amphetamines, ketamine, and cannabis were detected in almost every sample and often in high concentrations. Furthermore, two NPS were detected and a variety of over-the-counter medication and adulterants were also found. The findings were largely in-line with trends outlined in the European Drug Report. Striking were the relatively high concentrations of MDMA and ketamine and detection of two synthetic cathinones. Two possible adulterants of cocaine were detected, namely flecainide and amlodipine. Music festivals are considered a high-risk setting for alcohol consumption and illicit drug use. Analysis of pooled urine samples at a festival therefore provides a valuable method to evaluate trends and to screen for new substances. Wide-spread use of classical drugs and identification of two NPS were observed during a major international music festival in Belgium. Results need to be interpreted carefully, taking into account the possibilities and limitations of the used techniques and a standardized sampling is required.

Simple Extraction of Cannabinoids from Female Inflorescences of Hemp (Cannabis sativa L.)

The high interest in non-psychoactive cannabidiol increases the need for efficient and straightforward cannabidiol (CBD) extraction methods. The research aimed to compare simple methods of cannabinoid extraction that do not require advanced laboratory equipment. This work assesses the content of total CBD and Δ9-tetrahydrocannabinol (Δ9-THC) in popular solvents such as water and ethanol extracts. Hemp raw material was analyzed with Gas Chromatography with a Flame Ionization Detector (GC-FID), while extracts were tested by High-Performance Liquid Chromatography (HPLC). The female inflorescences of three varieties of industrial hemp were tested: Futura 75, KC Dora, and Tygra (different sowing and N fertilization densities). Tygra (T/10/30) showed the highest content of CBD (0.064%) in water extracts. However, in 80% tincture from Futura 75 (F/30/30), a higher CBD content of 1.393% was observed. The use of 96% ethanol for extraction and ultrasound enabled the highest CBD content to be obtained: 2.682% in Futura 75 (F/30/30). Cold water extraction showed no effect on Δ9-THC content, while hot water extraction increased content from 0.001% in KC Dora to 0.002% in Futura 75 (F/30/30) and Tygra, but the changes were statistically insignificant. Application of 80% ethanol revealed the significantly highest content of Δ9-THC in KC Dora, from 0.026% (K/30/90) to 0.057% (K/30/30), as well as in Tygra (T/30/30) (0.036%) and Futura 75 (F/30/30) (0.048%). The use of ethanol extraction in combination with ultrasound could be an efficient method of obtaining cannabinoids.

Effect of supercritical CO2 fractionation of Tahiti lemon (Citrus latifolia Tanaka) essential oil on its antifungal activity against predominant molds from pan bread

This study aimed to verify the in vitro antifungal activity of Tahiti lemon essential oil (LEO) and its fractions, obtained by supercritical CO2 fractionation, against Penicillium sumatrense and Aspergillus niger isolated from pan bread. For this, LEO was solubilized (20 MPa and 40 °C) and fractionated (10 MPa and 40 °C) in supercritical CO2, resulting in soluble (SF) and precipitated (PF) fractions. LEO, SF and PF volatile compounds were identified by gas chromatography coupled to mass spectrometry (GC–MS) and semiquantified by gas chromatography with a flame ionization detector (GC-FID). To evaluate the in vitro antifungal activity of the essential oils (LEO, SF and PF), the minimal inhibitory and fungicidal concentrations (MIC and MFC, respectively) were determined using the 96-well plate methodology. For this, pan breads ware prepared with no preservatives and stored for seven days at 25 °C, and their pH, water activity and moisture contents were determined. Then, two predominant species (Penicillium sumatrense and Aspergillus niger) were isolated from pan breads, characterized according to their morphological and molecular characteristics, and were used in the antifungal activity studies. LEO and its fractions presented monoterpenes, sesquiterpenes and their oxygenated derivatives in their composition. Specifically, limonene was the major component identified in the essential oils. SF showed greater antifungal potential than PF and LEO, showing that supercritical CO2 fractionation could improve the antifungal efficiency of LEO. The results suggest that LEO and its fractions may contribute to the inhibition of Aspergillus niger and Penicillium sumatrense growth in pan breads.

Chemical Characterization and Antibacterial Properties of Fontitrygon margarita (Günther, 1870) Liver Oil.

Objective The aim of this study was to determine the chemical characteristics and antibacterial activity of Fontitrygon margarita liver oil against the bacteria responsible for food poisoning. Methods Oils were extracted from F. margarita liver using two methods (exudation and cooking-pressing) and analyses by Fourier transform infrared (FTIR) spectroscopy. Quality indexes were determined using standard methods and the fatty acid profile was carried out by gas chromatography with a flame ionization detector (GC-FID). Antibacterial activities of these oils, their emulsion, and their interactions with common antibiotics were evaluated by the broth microdilution method. Results Extraction yield was higher with cooking-pressing (16.90%) compared to exudation (14.49%). The quality indexes of both oils were conformed to Codex Alimentarius Standard. Thiobarbituric acid index was higher with exudation compared to cooking-pressing (3.20 ± 0.14 and 2.36 ± 0.14 μmol MDA/kg, respectively) while acid, iodine, peroxide, and anisidine values did not significantly vary with the extraction methods (2.15-2.30 mgKOH/g, 102.42-106.65 gI2/100 g, 3.34-3.57 meqO2/kg, and 2.85-3.32 respectively). FTIR analyses clearly show that the two spectra are similar (no differences in the frequency and absorbance of their bands). The fatty acid profile revealed that, regardless of the extraction methods, F. margarita oil is richer in monounsaturated (55.97-55.41%) followed by polyunsaturated (28.17-28.52%) and saturated fatty acids (15.86-16.07%). Moreover, these oils showed antibacterial activity on all the bacteria strains tested with MICs between 16 and 256 mg/ml. Regardless of the extraction methods, emulsions showed higher activity (6.25 ≤ MIC ≤25 mg/ml) compared to crude oils. Additionally, F. margarita liver oil potentiated the antibacterial activity of ciprofloxacin, tetracycline, gentamicin, amoxicillin, and chloramphenicol. Conclusion These results showed the effectiveness of Fontitrygon margarita liver oil against some bacteria responsible for food poisoning, thus demonstrating their antibacterial properties which could be due to their chemical composition.

Understanding the early-stage release of volatile organic compounds from rapeseed oil during deep-frying of tubers by targeted and omics-inspired approaches using PTR-MS and gas chromatography

During deep-frying, a plethora of volatile products is emitted with the fumes. These compounds could act as oil quality indicators and change the indoor air composition leading to health risks for occupants. The presented experiments focus on deep-frying of different tubers in rapeseed oil at different frying temperatures. Here, two scenarios for real-time monitoring of volatile organic compounds (VOCs) using proton transfer reaction mass spectrometry (PTR-MS) were proposed. The first, targeted, involved the application of gas chromatography with a flame ionization detector (GC-FID). The second, omics-inspired, involved the use of solid-phase microextraction (SPME) along with gas chromatography-mass spectrometry (GC-MS) and molecular networking algorithm as a complementary tool to the PTR-MS analysis. In a targeted approach, it was shown that the emission profile of pentanal and hexanal depends on the frying temperature and as the temperature increases, a sudden release of these compounds can be observed in the first minutes of frying. Meanwhile, using an omics-inspired protocol enables finding the relation between 1,4-heptadienal and 2-heptanone, octanal and limonene emissions. Using both approaches it was possible to record real-time changes in emission profiles of various oils’ degradation products. It was also observed that the emission profiles of VOCs are strictly related to the frying temperature and the type of fried tuber.

Synergistic Adsorption of Organic Pollutants on Weathered Polyethylene Microplastics.

Microplastics (MPs) are persistent tiny pieces of plastic material in the environment that are capable of adsorbing environmental organic pollutants from their surroundings. The interaction of MPs with organic pollutants alters their environmental behavior, i.e., their adsorption, degradation and toxicity, etc. Polyethylene (PE) is the most widely used plastic material. The environmental weathering of PE results in changes to its surface chemistry, making the polymer a much better vector for organic pollutants than virgin PE. In this study, a laboratory-accelerated weathering experiment was carried out with a virgin PE film and an oxidatively degradable PE (OXO-PE) film, i.e., PE modified by the addition of a pro-oxidant catalyst. The degradation of PE and OXO-PE was assessed through Fourier transform infra-red (FTIR) spectroscopy and their wettability was measured by contact angle (CA) measurements. Their thermal properties and morphology were studied using thermogravimetric analyses (TGA) and scanning electron microscopy (SEM), respectively. Further, the adsorption of two model organic pollutants onto weathered and virgin PE was analyzed. Triclosan (TCS) and methylparaben (MeP) were chosen as model organic pollutants for the adsorption experiment due to their frequent use in the cosmetics industry, their uncontrolled release into the environment and their toxicity. The adsorption of both model pollutants onto PE and OXO-PE MP was analyzed by using gas chromatography with a flame ionization detector (GC-FID). The adsorption of MeP onto OXO-PE was higher than onto PE MPs. However, TCS showed insignificant adsorption onto PE and OXO-PE. When both pollutants were present simultaneously, the adsorption of TCS onto both PE and OXO-PE was significantly influenced by the presence of MeP. This result demonstrates that the adsorption behavior of one pollutant can be significantly altered by the presence of another pollutant. Both the effect of weathering on the adsorption of organic pollutants as well as the interaction between organic pollutants adsorbing onto MPs is highly relevant to actual MP pollution in the environment, where MPs are exposed to weathering conditions and mixtures of organic pollutants.

Weather Conditions Influence on Lavandin Essential Oil and Hydrolate Quality

Lavandula sp. essential oil and hydrolate are commercially valuable in various industry branches with the potential for wide-ranging applications. This study aimed to evaluate the quality of these products obtained from L. x intermedia cv. ‘Budrovka’ for the first time cultivated on Fruška Gora Mt. (Serbia) during three successive seasons (2019, 2020, and 2021). Essential oil extraction was obtained by steam distillation, and the composition and influence of weather conditions were also assessed, using flowering tops. The obtained essential oils and hydrolates were analysed by gas chromatography with a flame ionization detector (GC-FID) and gas chromatography coupled to mass spectrometry (GC-MS). A linear regression model was developed to predict L. x intermedia cv. ‘Budrovka’ essential oil volatile compound content and hydrolate composition during three years, according to temperature and precipitation data, and the appropriate regression coefficients were calculated, while the correlation analysis was employed to analyse the correlations in hydrolate and essential oil compounds. To completely describe the structure of the research data that would present a better insight into the similarities and differences among the diverse L. x intermedia cv. ‘Budrovka’ samples, the PCA was used. The most dominant in L. intermedia cv. ‘Budrovka’ essential oil and hydrolate were oxygenated monoterpenes: linalool, 1,8-cineole, borneol, linalyl acetate, and terpinene-4-ol. It is established that the temperature was positively correlated with all essential oil and hydrolate compounds. The precipitations were positively correlated with the main compounds (linalool, 1,8-cineole, and borneol), while the other compounds’ content negatively correlated to precipitation. The results indicated that Fruška Gora Mt. has suitable agro-ecological requirements for cultivating Lavandula sp. and providing satisfactory essential oil and hydrolate.