Gas Chromatograph-mass Spectrometer Research Articles

Aromatherapy was used to explore the sedative and hypnotic effects of Moringa seed essential oil on insomnia rats

AbstractMoringa is a type of plant that is used both for medicinal and food. Moringa seed (MS) are rich in volatile oil and have initially been employed to treat diseases of the nervous system. Insomnia, a prevalent neurological disorder, has led to this study's aim: to extract the essential oil from MS and analyze its potential to improve sleep. This study utilized petroleum ether for the thermal extraction of the essential oil from MS, which was then subjected to compositional analysis using Gas Chromatograph Mass Spectrometer (GC–MS). P‐chlorophenyl alanine (PCPA) was used to induce an insomnia model in Sprague–Dawley (SD) rats. Following the successful establishment of the model, the MS essential oil was administered at concentrations of 10%, 5%, and 2.5% to investigate its sedative and hypnotic effects. The efficacy of the MS essential oil was assessed by observing the general condition of rats in each group, conducting an open field test, a pentobarbital sodium righting test, and measuring the serum 5‐HT (5‐hydroxytryptamine) levels and hypothalamic GABA (γ‐aminobutyric acid) content. GC–MS analysis of the MS essential oil revealed a rich composition, including oleic acid, palmitoleic acid, stigmasterol, and γ‐stigmasterol, among other substances. Through the assessment of the rats' general condition, behavioral tests, and blood biochemical assays, it was inferred that MS essential oil aromatherapy can reduce the rat's locomotor activity, increase their interest in activity and exploration, enhance the serum 5‐HT levels, and elevate hypothalamic GABA content. Consequently, it can be concluded that MS essential oil has a sedative and hypnotic effect.

Associations between VOCs and childhood asthma in Shanghai, China: impacts of daily behaviors

Exposure to volatile organic compounds (VOCs) detected in indoor environments may have negative impacts on childhood health. However, the associations between indoor VOCs and childhood asthma, considering daily behaviors, have rarely been conducted. Based on the case-control study with field measurement, we collected air samples from 358 children’s bedrooms. Concentrations of VOCs in air samples were measured by chemical treatment and gas chromatography-mass spectrometer. Logistic regression models were applied to investigate the associations between VOCs with childhood asthma. Meanwhile, stratification analysis was performed to reveal the influences of daily behaviors (window opening during night, using household chemical products, and bedroom cleaning) on the target associations. A new assessment indicator considering multiple VOCs was proposed to investigate the combined effects of multiple VOCs on childhood asthma. High concentrations of toluene (the highest adjusted odds ratio (AOR) was 2.59), o-xylene (AOR: 2.01), xylene (2.24), dodecane (the highest AOR was 2.57), pentadecane (2.82), hexadecane (2.04), α-pinene (1.99), total volatile organic compounds (TVOC) (the highest AOR was 2.94), and the new indicator of aromatics (the highest AOR was 2.59) were significantly associated with childhood asthma. The daily behaviors of the residents can significantly affect the target associations, with the window opening during night having the most significant effect, followed by bedroom cleaning and using household chemical products. Families with lifetime asthmatic children may have specific avoidance behaviors for the potential environmental factors on children’s health. These behaviors could explain that VOCs exposure had significant associations with the decreased odds of childhood asthma.

Phytochemical Analysis and Biological Evaluation of Andrographis paniculata (Burm.f.) Wall. ex Nees, from Nigeria

The medicinal plant, Andrographis paniculata (Burm.f.) Wall. ex Nees, used in Nigeria's ethno-medicine, was investigated for its radical scavenging and antimicrobial properties, as well as its phytochemical composition, using gas chromatography-mass spectrometric (GC-MS) analysis. In vitro antioxidant activity of the methanol extract of the whole plant was tested through four different assays: DPPH, ABTS, FRAP, and NOx. The GC-MS analysis revealed the presence of neophthadiene (29.42%), followed by ergost-5-en-3-ol (10.57%), and methyl sterate (7.29%) as the major compounds present in the methanol extract of Andrographis paniculata. The methanol extract showed promising antioxidant activity compared with the reference (ascorbic acid). It was observed that the activity was concentration dependent, and values of 86.12±0.03, 90.18±0.03, 80.20±0.04, and 92.15±0.06 were obtained for DPPH, ABTS, FRAP, and NOx, respectively, under the same condition. All the tested bacteria (gram positive and gram negative) were inhibited by the methanol extract of Andrographis paniculata, except Proteus mirabilis, which showed a resistance at lower concentrations (0.25 mg/ml and 0.50 mg/ml). These findings suggest the bioactive potentials of Andrographis paniculata (Burm.f.) Wall. ex Nees, supporting its traditional use in Nigerian ethnomedicine and highlighting potential applications in pharmaceuticals.

In-tube extraction dynamic headspace coupled to gas chromatography-mass spectrometry for the sensitive analysis of volatile compounds in aqueous samples

Aim: Volatile organic compounds (VOCs) are often human-made contaminants used and generated in the manufacturing of numerous products, presenting notable environmental and health hazards. Therefore, the development of sensitive and reliable analytical methods is crucial for their detection with accuracy, timeliness, and automation capabilities. The objective of this study is to demonstrate the suitability of the in-tube extraction dynamic headspace (ITEX-DHS) sampling method for the gas chromatographic/mass spectrometric (GC/MS) analysis of BTEX (benzene, toluene, ethylbenzene, and xylenes) compounds in aqueous matrices. It emphasizes the method’s metrological reliability and innovative approach to precisely determining VOCs in aqueous environments providing a tool to prevent contamination of the agrifood sector. Methods: Following the optimization of various experimental parameters, including salt incorporation and adjustments of both dry purging and desorption conditions. The method’s performance was evaluated for repeatability, reproducibility, and robustness. Results: Limit of detection (LOD) and limit of quantification (LOQ) were for all substances determined lower than 50 and 100 ng/L, respectively. Average relative standard deviations below 5% were achieved for all analytes, with recovery rates ranging between 93% and 101%. Subsequently, the method was applied for the determination of BTEX in one hundred groundwater samples. The findings revealed that the BTEX levels were below the LOD in 84.2% of samples. However, in the remaining samples, more than one compound was detected at concentrations higher than the LOQ. Conclusions: The ITEX method emerges as a highly favorable alternative to both solid phase microextraction (SPME) and purge and trap (P & T) methods for determining BTEX in aqueous samples, providing significant advantages. Its strengths lie in its increased robustness, extended trap lifespan, and enhanced sensitivity, underscoring its superior performance in VOC analysis. The total analytical method allows the sensitive and robust determination of VOC.

Sedimentary factors controlling the organic matter enrichment in oil shale, Seyitömer Lacustrine Basin, Western Anatolia: New implications from organic and inorganic geochemistry

AbstractWestern Anatolia, an important segment of the Alp‐Himalayan Belt, hosts numerous Neogene lacustrine basins with potential oil shale reserves surpassing 1.6 billion tonnes. Among these basins, the Seyitömer Basin (Kütahya) stands out, containing oil shales that are intercalated with claystone, marl, limestone and coal layers. This study presents a comprehensive dataset of organic and inorganic chemistry to gain insight into the palaeoclimate and palaeoenvironmental factors that control the enrichment of organic matter. The studied samples exhibit high total organic carbon contents, averaging 12.85% (ranging from 2.22 to 36.21%), high hydrogen indices (486–812 mgHC/g rock) and low oxygen indices (33–70 mgCO2/g total organic carbon), indicating their substantial hydrocarbon‐source potential. These characteristics indicate predominantly ‘excellent’ to occasionally ‘very good’ source rock qualities and very high oil potential. Their pyrolysis, gas chromatography and gas chromatography–mass spectrometer parameters indicate an immature‐early mature characteristic for Seyitömer oil shale samples. They comprise dominantly Type‐I kerogen with minor Type‐II kerogen and lacustrine algal organic matter. Their sedimentological characteristics, along with various geochemical values, such as total organic carbon versus S, B versus Ga and dibenzothiophene/phenanthrene, reveal a moderately deep fresh/brackish to saline lacustrine environment. The Ga/Rb, K/Al and Sr/Cu ratios suggest dominantly humid and warm climate conditions, occasionally interrupted by periods of less humidity. The prevalence of warm and humid climate conditions leads to intense chemical weathering processes, supported by high Chemical Index of Alteration and low Rb/Sr ratios in the associated oil shale samples. Intense chemical weathering and high runoff resulted in dissolved nutrient enrichment, promoting ecological dynamics favourable to increased productivity. Their low Pr/Ph and Mo/total organic carbon ratios, high Ni/Co ratio and, relatively low MoEF/UEF ratio, along with well‐developed lamination of the oil shales, indicate the presence of anoxic conditions in the bottom water. These anoxic conditions would have facilitated the preservation potential of organic matter in the samples. Thus, the palaeoclimate conditions integrated with sedimentary factors have an important role in the ecological dynamic and physical–chemical environmental conditions, ultimately contributing to the organic matter enrichment of the studied samples. This work provides a case study to better understand the sedimentary factors controlling organic matter enrichment in the lacustrine basins of the Alp‐orogenic belt.

Chemical Fingerprinting, PAHs Characterization and Ecological Risks of Carcinogenic PAHs in Surficial Sediments of Egi Crude Oil Producing Communities, Niger-Delta, Nigeria

In order to do PAHs rings analysis, its source identification, extent to which cPAHs present and what kind of ecological risk they pose, the surface sediments from various freshwaters in the Egi crude oil producing cities in the Niger Delta, Nigeria were analyzed. Sediments collected from the research areas for PAHs loadings (in mg/kg dry weight) ranged from 0.020 to 1.790, 0.050 to 1.880, and 0.020 to 1.640, respectively for Obite, Obagi, and Ibewa cluster areas, as measured by gas chromatography-mass spectrometer. In these clusters, the respective average concentration of the three dominant carcinogenic PAHs were Indeno(1,2,3-cd)pyrene (1.170.0mg/kg), Dibenz[a,h]anthrancene (0.870.0 mg/kg), and Dibenz[a,h]anthrancene (1.3670 mg/kg) for Ibewa, Obagi and Obite cluster areas. The findings showed that dominant PAHs rings are of high molecular weight (HMW) PAHs in these sediments are, 5 member rings, which are benzo(b)fluoranthene, Benzo(k)fluoranthene, and Benzo(a)pyrène, and 6-member ring which are, Indeno(1,2,3-cd)pyrene, Dibenz[a,h]anthrancene, and Benzo[ghi] perylene, respectively. Their fingerprints points majorly to pyrogenic sources, combustion of coal, biomass, petroleum, and other related anthropogenic petroleum activities as the primary source of PAHs in the environment. Notably, the RQNCs and RQMPCs for single PAHs molecule are both less than 1, it means the contamination it generates is considered of low ecological risk. Again, the research area experiences frequent flooding, it is believed that this contributes to the low ecological risk of PAHs chemical pollution. Consequently, the area is deemed to be quite safe.

Pentaethylphenol (Not 2,6-di-tert-butyl-4-ethylphenol) verified as the primary product of guaiacol ethanol alkylation reaction

Guaiacol ethanol alkylation (GEA), a model reaction of lignin solvolysis, has been intensively investigated. However, the product identification with gas chromatograph-mass spectrometer (GC-MS) was wrong due to the defect of the GC-MS databases. In this work, the main product was isolated with a flash chromatography technique and analyzed with 1H NMR and was identified as ethyl fully substituted phenol (or pentaethylphenol), which is contrary to the reported 2,6-di-tert-butyl-4-ethylphenol in previous literature. The NMR analysis of the entire product mixture further confirms that the product only contains ethyl substituted molecules, with no existence of isopropyl or tert-butyl substituted products. The byproducts, including ethyl partially substituted phenols, i.e., tetraethylphenol and triethylphenol, ethyl partially substituted guaiacol, 2-ethoxyphenol, and pentaethylbenzene, were also speculated based on the MS spectra. These findings rectify a long-standing error in product identification and may offer critical insights for mechanism investigations.

Pressurized hydrogasification and cobalt-catalyzed hydrogasification behaviors of naphthalene as a coal-based model compound

The pressurized hydrogasification/catalytic hydrogasification behaviors of naphthalene as a coal-based model compound were investigated for the first time in a batch reactor. The composition of products was roundly analyzed by gas chromatography (GC), gas chromatography–mass spectrometer (GC-MS) and laser desorption time-of-flight mass spectrometry (TOF-MS). Based on the product analysis results, the detailed reaction pathways for naphthalene hydrogasification and the effects of cobalt on reaction pathways were elucidated. Naphthalene first destabilized during hydrogasification. Subsequently, the destabilized naphthalene either underwent stepwise hydrocracking by active hydrogen atoms to ultimately produce benzene and methane, or formed naphthalene free radicals to initiate condensation. Cobalt can regulate products distribution to boost methane, benzene and toluene yield by facilitating active hydrogen generation, despite it had a limited ability to facilitate the naphthalene destabilization at temperature below 700 °C. Whereas above 750 °C, cobalt can promote naphthalene destabilization, thereby remarkably enhancing the conversion of naphthalene. Furthermore, cobalt intensified condensation leading to a shift of molecular mass distribution of condensation products from 252 ∼ 500 Da to 750 ∼ 2000 Da. These phenomena supported similar findings in coal catalytic hydrogasification. The rise in temperature, initial H2 pressure (P0), and cobalt content all facilitated the cobalt catalyzed naphthalene hydrocracking to gaseous product, with temperature exerting a particularly significant effect. This trend was similar with cobalt catalyzed coal hydrogasification. For example, when temperature increased from 650 ℃ to 750 ℃, naphthalene conversion improved from 21.2 % to 49.6 %, and gas yield rose from 2.6 % to 29.4 % at 1 % Co and 1.3 MPa P₀. The investigation serves to shed light on the molecular-level understanding of the mechanism underpinning coal hydrogasification.

Source-specific probabilistic health risk assessment of dust PAHs in urban parks based on positive matrix factorization and Monte Carlo simulation.

Understanding the health risks of polycyclic aromatic hydrocarbons (PAHs) in dust from city parks and prioritizing sources for control are essential for public health and pollution management. The combination of Source-specific and Monte Carlo not only reduces management costs, but also improves the accuracy of assessments. To evaluate the sources of PAHs in urban park dust and the possible health risks caused by different sources, dust samples from 13 popular parks in Kaifeng City were analyzed for PAHs using gas chromatograph-mass spectrometer (GC-MS). The results showed that the surface dust PAH content in the study area ranged from 332.34µg·kg-1 to 7823.03µg·kg-1, with a mean value of 1756.59µg·kg-1. Nemerow Composite Pollution Index in the study area ranged from 0.32 to 14.41, with a mean of 2.24, indicating that the overall pollution warrants attention. Four pollution sources were identified using the positive matrix factorization (PMF) model: transportation source, transportation-coal and biomass combustion source, coke oven emission source, and petroleum source, with contributions of 33.74%, 25.59%, 22.14%, and 18.54%, respectively. The Monte Carlo cancer risk simulation results indicated that park dust PAHs pose a potential cancer risk to all three populations (children, adult male and adult female). Additionally, the cancer risk for children was generally higher than that for adult males and females, with transportation sources being the main contributor to the carcinogenic risk. Lastly, sensitivity analyses results showed that the toxic equivalent concentration (CS) is the parameter contributing the most to carcinogenic risk, followed by Exposure duration (ED).

Unique sterol metabolite shifts in inflammatory bowel disease and primary sclerosing cholangitis

Inflammatory bowel disease (IBD) triggers chronic intestinal inflammation and is linked to primary sclerosing cholangitis (PSC). Cholesterol homeostasis, tightly regulated under normal conditions, becomes disrupted in both inflammation and chronic liver disease. We analyzed fecal and serum levels of cholesterol synthesis precursors, oxysterols, and phytosterols in 87 patients with IBD (81 for serum analysis) including patients with Crohn's disease (CD) and ulcerative colitis (UC), 11 patients with PSC, 21 patients with PSC-IBD (18 for serum analysis), and 16 healthy controls (17 for serum analysis). Cholesterol was analysed by flow injection analysis on a high-resolution hybrid quadrupole-Orbitrap mass spectrometer and further serum sterols and all fecal sterols were analysed by a gas chromatograph mass spectrometer. Serum levels of lanosterol, 7-dehydrocholesterol, 7-beta-hydroxycholesterol, 27-hydroxycholesterol, and the plant sterols campesterol, stigmasterol, and sitosterol were similar across control and patient groups. Notably, serum lathosterol was elevated in CD patients compared to those with UC, PSC, PSC-IBD, and healthy controls. All other serum and fecal sterols showed no differences between CD and UC. Cholesterol synthesis precursors in serum, serum cholesterol levels, and both serum and fecal plant sterol levels decreased with increasing IBD severity. Consequently, serum cholesterol, campesterol, sitosterol, and fecal 5-beta sitostanol and 5-alpha sitostanol were negatively correlated with C-reactive protein and fecal calprotectin. The conversion of cholesterol to coprostanol in feces was impaired in IBD, PSC, and PSC-IBD, independent of bowel inflammation severity or liver disease extent. Patients with PSC, and to a lesser extent PSC-IBD, had elevated serum plant sterol levels, positively correlating with liver disease markers. In conclusion, in patients with IBD, cholesterol biosynthetic precursors, serum cholesterol levels, and fecal plant sterols decrease with intestinal inflammation. An inverse association of serum plant sterols with intestinal inflammation was observed in patients with IBD and a direct association of serum phytosterols with liver injury in patients with PSC. The conversion of fecal cholesterol to coprostanol was impaired in all patient cohorts. IBD and PSC alter serum sterol levels differently, whereas changes in fecal sterols are not disease specific and are moderate.

Association between full blood count and urine steroid metabolome in patients with adrenal masses

Background: Endogenous hypercortisolism of adrenal origin is commonly associated with immune suppression. However, these patients also have signs characteristic of chronic inflammatory diseases. Better understanding of the mechanisms that alter the functioning of the immune system would allow for the development of a patient-centered approach to the treatment of corticotropin-independent endogenous Cushing's syndrome (CS). Aim: To assess the association between full blood count and gas chromatography-mass spectrometry-based urinary steroid excretion in patients with adrenal masses depending on malignancy grade and presence of hypercortisolism. Materials and methods: We retrospectively analyzed data from 42 patients with adrenal masses who had not received chemotherapy. The median age of the patients was 54 [Q25; Q75: 37; 63] years, and 76% of them were female. Preoperatively, all patients had hematology tests with differential leukocyte count. Steroid metabolome was assessed with Shimadzu GCMS-TQ8050 gas chromatography-mass spectrometer. Results: Twelve (12) patients had adrenocortical cancer (ACC) and CS, 9 patients had ACC without CS, 11 had adrenocortical adenomas (ACA) and CS, and 10 patients had ACA without CS. ACC patients had a higher neutrophil-to-lymphocyte ratio (NLR) than those with ACA: 3.35 [2.5; 6.3] vs 1.99 [1.41; 2.65] (р = 0.001). There was a linear correlation between NLR and serum cortisol levels after the 1 mg overnight dexamethasone suppression test (r = 0.41, p = 0.01), urinary excretion of 5β-tetrahydrocortisol (5β-THF) (r = 0.71, p 0.001) and 11β-hydroxyandrosterone (11β-OH-An) (r = 0.74, p 0.001). The ACC patients without CS had lower 5β-THF urinary excretion values, compared to ACA with CS patients: 931 [616; 1610] and 3139 [1480; 4375] mcg/24h, respectively (р = 0.007). 11β-OH-An urinary excretion in ACC patients without CS was higher than in ACA patients with CS: 1170 [806; 1266] и 602 [320; 739] mcg/24h (р = 0.007). The NLR cut-off value for adrenal mass malignancy in patients with CS exceeded 2.72 (sensitivity 90.0%, specificity 80.0%), and for the patients without hypercortisolism was above 1.92 (sensitivity 71.4%, specificity 100.0%). Conclusion: This is the first association identification between NLR, which is the marker of systemic inflammation, inflammation, and urinary excretion of 11β-OH-An, a metabolite of 11-hydroxyandrostenedione (a member of 11-oxygenated androgen family). This extends our understanding of the impact of hormonal activity of adrenal mass cells on the immune system.

Polycyclic aromatic hydrocarbons (PAHs) in crude oil-contaminated water and soil and their removal using locally available plant materials

ABSTRACT The presence of polycyclic aromatic hydrocarbons (PAHs) in water and soil can be harmful to human life when ingested. PAHs are determined in the water and soil of the B-Dere community of Rivers State, Nigeria. The extent of risk and source identification were carried out. The water samples were treated with garlic and Moringa seed extracts, while the soil samples were treated with garlic and Fenton oxidation reagents. PAHs were extracted before and after treatment. The gas chromatograph mass spectrometer analyses showed 13 PAHs in the water and 10 PAHs in thesoil. The highest concentration in water was recorded for benzo(ghi)perylene, with a mean value of 27.7 ± 0.25 ngL−1, while that of soil was recorded for benz(a)anthracene, with a mean value of 14.4 ± 0.631 ngkg−1. The source of PAHs in water was pyrogenic, while that of soil was petrogenic. Garlic extract removed 100% of benz(a)anthracene and benzo(b)fluorothane from the water, while Moringa removed 100% biphenylene from the water. However, garlic extract removed 2.59% of acenaphthylene, while Fenton reagents removed 100% of anthracene, phenathrene, and chrysene from the soil. Moringa seed and garlic extracts can be used in PAH's polluted water treatment.

Exposure assessment of pesticide residues, heavy metals, and veterinary drugs through consumption of Egyptian fish samples

Environmental contaminants may enter seafood products either through water and sediments or via feed and feed additives or may be introduced during fish processing and storage. The study focused on the nutritional and toxicological significance of heavy metals, antibiotics, and pesticide residues in 48 fish samples collected from the Kafr-ElSheikh governorate in Egypt. Various analytical instruments are used to determine and detect heavy metals, antibiotics, and pesticides. These include Liquid Chromatography Tandem Mass Spectrometer (LC-MS/MS), Inductively Coupled Plasma Mass Spectrometer (ICP-MS), and Gas Chromatography-Mass Spectrometer (GC-MS). The following metals were discovered in fish species: arsenic (As), cadmium (Cd), cobalt (Co), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), and zinc (Zn). Each of these metals was detected 47 times. Chromium (Cr) was detected 40 times, nickel (Ni) was detected 27 times, and lead (Pb) was detected 6 times. The mean concentrations of As, Cd, Cr, Co, Cu, Fe, Ni, Mn, Hg, Pb, and Zn were determined to be 0.025, 0.02, 0.501, 0.50, 0.81, 12.56, 0.5, 0.689, 0.051, 0.031, and 5.78 mg/kg, respectively. All levels of cadmium, mercury, and lead detected in fish samples were significantly lower than the maximum permissible limits set by Egyptian and European standards. Furthermore, in this study, antibiotics and pesticide residues were found to be not detected in all analyzed fish samples. Based on the estimated daily intake and hazard quotient values, the concentration levels of metals found in fish samples seem to pose no significant threat to public health.

Reanalysis of the Huygens GCMS dataset. I. High-resolution methane vertical profile in the atmosphere of Titan

More than 15 years after its landing on the surface of Titan, the data returned by the Huygens probe remain the only available in situ information on Titan’s lower atmosphere and its methane content. In this work, we present a reanalysis of the Huygens probe data obtained by the Gas Chromatograph Mass Spectrometer (GCMS) instrument on board Huygens. GCMS measured the atmospheric composition almost continuously during the Huygens probe descent by acquiring mass spectra between 145 km of altitude and Titan’s surface. We first focus on the recollection, reconstruction, and recalibration of the GCMS dataset to facilitate similar future work. We then reevaluate the methane vertical profile in Titan’s lower atmosphere by applying novel mass spectra data-treatment methods to this dataset. In addition to finding a slightly lower methane mixing ratio than those previously reported using GCMS measurements above the Huygens probe landing site, our work has revealed several kilometric to subkilometric-scale oscillations in the methane vertical profile below 30 km of altitude. We discuss several hypotheses that could explain these features, such as multiple layers of optically thin clouds or local convection cells, and strongly encourage the reanalysis of other Huygens datasets to further investigate these variations in the methane mixing ratio.

Inhibitory Mechanism of the Oregano Essential Oil on the Growth and Biofilm Formation of Streptococcus mutans

Objective: The objective was to determine the in vitro antibacterial effect of the Oregano essential oil (OEO) on Streptococcus mutans ( S mutans) and to explore the anti-biofilm effect and mechanism of OEO. Methods: The in vitro antibacterial susceptibility of OEO was detected by the growth curve and colony-forming unit (CFU) counting method. Confocal laser scanning microscope (CLSM) and crystal violet assay were used to explore the anti-biofilm activity of OEO, and the anti-biofilm mechanism was explored from the aspects of extracellular polysaccharides (EPS) synthesis, acidoid, and extracellular DNA changes. OEO was characterized using a gas chromatography-mass spectrometer and cytotoxicity was tested using a cell counting Kit-8 assay. Results: The minimum inhibitory concentration of OEO was 0.25 mg/mL, and the CFU showed the ability of OEO to kill planktonic bacteria. Scanning electron microscopy and CLSM showed that OEO could hinder the development of biofilms, harm bacteria, and eliminate mature biofilms by changing EPS synthesis and pH value. Carvacrol in OEO played a major role in biological antibacterial activity. OEO had low cytotoxicity and good biocompatibility. Conclusions: OEO had excellent antibacterial and anti-biofilm effects on the key virulence traits of S mutans, indicating potential prospects in preventing dental caries.

Isolation, purification, and structural elucidation of a water-soluble polysaccharide derived from Phellinus baumii Pilát mycelia

This study involved the successful production of mycelial polysaccharides by optimizing submerged culture conditions of Phellinus baumii Pilát. Then, the investigation focused on the composition and chemical structure of the water-soluble polysaccharide from P. baumii Pilát mycelia (PBMP) by extraction and purification. Specifically, this study indicated that a water-soluble PBMP fraction 1 (PBMP1) was isolated from PBMP. Moreover, this study discovered a PBMP1 isolated from PBMP, which was found to have the monosaccharide compositions comprised of fucose (Fuc), glucose (Glc), and galactose (Gal) despite the absence of proteins. Subsequently, the composition and structure of PBMP1 were characterized using Fourier transform infrared (FT-IR) spectroscopy, periodate oxidation, Smith degradation, methylation reaction, gas chromatography-mass spectrometer (GC-MS), and Nuclear magnetic resonance (NMR). The composition and structure of PBMP1 were characterized in this study, revealing an α-glycosidic bond conformational linkage with 1,4-Glc residues and 1,6-Gal residues forming the backbone. Additionally, a highly branched hetero-polysaccharide was identified with a non-reducing terminus of Fuc containing 1,3,4- and 1,4,6-Glc branching. The findings of this study offer valuable insights and information that can be utilized by researchers, manufacturers, and other stakeholders to advance the field of P. baumii Pilát product development. Moreover, these results have significant implications for future large-scale mass production and functional applications of PBMP1 products.

Occurrence, source identification and risk assessment of polybrominated diphenyl ethers in water and sediments of Osun River, Nigeria

BackgroundIn the present study, the concentrations of polybrominated diphenyl ethers (PBDEs) in water and sediments of Osun River, Nigeria were determined.MethodsThe obtained water samples were subjected to liquid-liquid extraction while the sediment samples were subjected to extraction using n-hexane and acetone. The extracts were quantified using a Gas Chromatography-Mass Spectrometer to assess their distribution, source identification, and ecological risk assessments.ResultsThe results of the study indicated that BDE-99, BDE-183, and BDE-209 were not detected in the water samples while BDE-28 had the most significant mean contribution (0.057 mg/L w.w) to the total PBDEs in the water samples. The sediment samples were dominated by enhanced concentrations of BDE-100 congener (mean concentration 0.184 mg/kg d.w). The compositional profiles of the PBDE congeners indicated the abundance of higher BDEs in the sediment samples compared to the water samples, a phenomenon attributed to the lower reduction rate and lower water solubility of the higher BDEs. Source identification indicated that commercial deca-BDE mixtures might represent the major source of PBDEs in the studied river. Risk assessment of PBDEs in water samples showed that the mean concentrations of tri-BDE, tetra-BDE, penta-BDE, and hexa-BDE exceeded the acceptable limits, suggesting adverse health risks to the public. Ecological risk assessment of PBDEs in sediment samples showed medium ecological risk by hexa-BDE (0.1 ≤ RQ ≤ 1) and high ecological risks due to tri-, tetra-, penta-, and deca-BDEs (RQ > 1).ConclusionThe study concludes that efficient and cost-effective remediation strategies should be developed and employed in the abatement of these persistent organic pollutants from the environment.

Microbial succession and flavor impact during natural fermentation of Tartary buckwheat sourdough

In this study, the succession process and driving mechanisms of microbial communities during the fermentation of Tartary buckwheat sourdough were explored using high-throughput sequencing and microbiome co-occurrence network analysis. A gas chromatograph–mass spectrometer (GC–MS) was used to monitor the dynamic evolution of flavor compounds in Tartary buckwheat sourdough at different fermentation stages. Using GC–MS and principal component analysis, 47 volatile compounds were identified as the main differential volatile compounds during fermentation. The predominant bacterial genera observed in the natural fermentation of Tartary buckwheat sourdough included Enterococcus, Weissella, Cronobacter, Lactococcus, and Pediococcus. Among fungi, Alternaria, Botrytis, Trichothecium, and Vishniacozyma were the dominant genera. The correlation analysis results revealed that Weissella, Pediococcus, Lactobacillus, Acinetobacter, and Vishniacozyma were the core functional microbes involved in flavor formation. Organic acids were the primary driving force for microbial succession. This study provides a better understanding of the relationship between microbial communities and volatile components in the natural fermentation process of Tartary buckwheat sourdough as well as useful information for improving the flavor quality of Tartary buckwheat sourdough products, thereby helping to choose starter cultures with flavor modulation ability.

Add-On Device Powered by Parallelized Adsorption Traps for Preconcentrator-GC-MS Measurement of sub-pmol/mol Levels of NF3.

In this study, an add-on preconcentration device powered by parallelized pretraps (PPTs) was utilized to measure the sub-pmol/mol levels of NF3 in N2. The add-on preconcentrator was coupled to the detachable trap preconcentrator (DTP) with a gas chromatograph-mass spectrometer [Anal. Chem. 2019, 91, 3342-3349]. The breakthrough volume of the parallel configuration was found to be substantially higher than that of the serial configuration with the same amount of adsorbent (HayeSep D). Liquid oxygen (LO2) cooling (-183 °C) exhibited better preconcentration performance for NF3 in N2 compared to NF3 in air (N2 + O2) with liquid nitrogen cooling (-195 °C) and NF3 in air with LO2 cooling. The DTP unit was essential to discriminate residual species, such as N2, O2, CO2, and CF4, of which the preconcentrated portion in the PPT can be excessive, enabling the overwhelm filtering capability of the quadrupole mass spectrometer. The limit of detection of NF3 in N2 of the PPT/DTP/gas chromatograph-mass spectrometer was 0.01 ppt, which is significantly better than that determined without using the add-on preconcentration device (0.21 ppt).

Identification and simultaneous quantification of potential genotoxic impurities in first-line HIV drug dolutegravir sodium using fast ultrasonication-assisted extraction method coupled with GC–MS and in-silico toxicity assessment

Dolutegravir (DLG) has become a distinctive first-line antiretroviral therapy for the treatment of HIV in most countries due to its affordability, high efficacy, and low drug-drug interactions. However, the evaluation of genotoxic impurities (GTIs) in DLG and their toxicity assessment has not been explored thoroughly. Thus, in this study, a simple, fast, and selective analytical methodology was developed for the identification and determination of 7 GTIs in the comprehensive, explicit route of synthesis for the dolutegravir sodium (DLG-Na) drug. A facile, fast ultrasonication-assisted liquid–liquid extraction procedure was adapted to isolate the GTIs in DLG-Na and then analyzed using the gas chromatography (GC)-electron impact (EI)/mass spectrometer (MS) quantification (using selective ion monitoring mode) technique. This EI-GC/MS method was validated as per the current requirements of ICH Q2 (R1) guidelines. Under optimal method conditions, excellent linearities were achieved with R between 0.9959 and 0.9995, and high sensitivity was obtained in terms of detection limits (LOD) between 0.15 to 0.63 µg/g, and quantification limits (LOQ) between 0.45 to 1.66 µg/g for the seven GTIs in DLG. The obtained recoveries ranged from 98.2 to 104.3 % at LOQ, 15 µg/g, and 18 µg/g concentration levels (maximum daily dose of 100 mg). This developed and validated method is rapid, easy to adopt, specific, sensitive, and accurate in estimating the seven GTIs in a relatively complex sodium matrix of the DLG-Na drug moiety. As a method application, two different manufactured samples of DLG-Na drug substances were analyzed for the fate of the GTIs and drug safety for the intended dosage applications. Moreover, an in-silico QSAR toxicity prediction assessment was carried out to prove scientifically the potential GTI nature of each impurity from the alerting functional groups.