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Co-adsorption of gaseous benzene, toluene, ethylbenzene, m-xylene (BTEX) and SO2 on recyclable Fe3O4 nanoparticles at 0-101% relative humidities.

We herein used Fe3O4 nanoparticles (NPs) as an adsorption interface for the concurrent removal of gaseous benzene, toluene, ethylbenzene and … iencies. Adsorption experiments of BTEX on NPs were measured using gas chromatography equipped with flame ionization detection, which indicated high removal efficiencies (up to (95±2)%) under dry conditions. The humidity effect and competitive adsorption were investigated using toluene as a model compound. It was observed that the removal efficiencies decreased as …

Systemic availability and pharmacokinetics of thymol in humans.

Essential oil compounds such as found in thyme extract are established for the therapy of chronic and acute bronchitis. Various pharmacodyna … tic hydrolysis of the metabolites by headspace solid-phase microextraction prior to GC analysis and flame ionization detection. Thymol sulfate, but not thymol glucuronide, was detectable in plasma. Peak plasma concentrations were 93.1+/-24.5 ng ml(-1) and were reached after 2.0+/-0.8 hours. The mean terminal elimination half-life was 10.2 hours. Thymol sulfate was …

Occurrence and determination of organic pollutants in tap and surface waters of the Gdańsk district.

The results of the determination of different classes of organic pollutants (trihalomethanes, polycyclic aromatic hydrocarbons (PAHs), pesti … CD) for determination of volatile organohalogen compounds: purge and trap with a gas chromatography-flame ionization detection for determination of volatile hydrocarbons; sorption on solid sorbent XAD-4 or C18, elution with organic solvent and GC-ECD for determination of pesticides; sorption on solid sorbent C18, elution with organic solvent and a gas chromatograp …

Discrepancies in Mineral Oil Confirmation by Two-Dimensional Gas Chromatography-Mass Spectrometry: A Call for Harmonization.

Three different vegetable oils, namely coconut oil, palm olein and olive oil, were analyzed for mineral oil hydrocarbons (MOHs) in our laboratory and in five commercial laboratories well recognized for their expertise in this field. The analysis consisted of a preliminary quantitative estimation of MOH content by hyphenated liquid chromatography-gas chromatography with flame ionization detection (LC-GC-FID), followed by a confirmatory analysis of MOH components by two-dimensional gas chromatography with time-of-flight mass spectrometry (GCxGC-ToF). The results provided by the six laboratories …

In-line gas chromatographic apparatus for measuring the hydrophobic micropore volume (HMV) and contaminant transformation in mineral micropores.

Desorption of hydrophobic organic compounds from micropores is characteristically slow compared to surface adsorption and partitioning. The … acked with the microporous sorbent is coupled directly to a gas chromatograph that is equipped with flame ionization and electron capture detectors. Sorption and desorption of TCE on the sorbent was measured by sampling the influent and effluent of the column using a combination of switching and injection valves. For geosorbents, the HMV is quantified based on Gur …

Factors affecting the accuracy of blood alcohol determinations in clinical and forensic laboratories in Italy: Results of a 7-year proficiency testing study.

The results of a 7-year proficiency study involving Italian laboratories measuring blood alcohol concentration (BAC) are reported. Two blood samples spiked with known amounts of ethanol were sent for analysis twice per year to approximately 50 laboratories across Italy. The blood samples were prepared according to ISO standards, which included optimized transport and storage conditions to ensure ethanol stability. Participants completed an online questionnaire detailing their analytical results along with other analytical details, including the use of GC-FID or GC-MS, storage temperature, time

Effect of trichloroethylene and tetrachloroethylene on methane oxidation and community structure of methanotrophic consortium.

The methane oxidation rate and community structure of a methanotrophic consortium were analyzed to determine the effects of trichloroethylene (TCE) and tetrachloroethylene (PCE) on methane oxidation. The maximum methane oxidation rate (Vmax ) of the consortium was 326.8 μmol·g-dry biomass(-1)·h(-1), and it had a half-saturation constant (Km ) of 143.8 μM. The addition of TCE or PCE resulted in decreased methane oxidation rates, which were decreased from 101.73 to 5.47-24.64 μmol·g-dry biomass(-1)·h(-1) with an increase in the TCE-to-methane ratio, and to 61.95-67.43 μmol·g-dry biomass(-1)·h(-1

Vitiquinolone--a quinolone alkaloid from Hibiscus vitifolius Linn.

Phytochemical investigations of the powdered root of Hibiscus vitifolius Linn. (Malvaceae) was extracted successively with n-hexane and chloroform. Analysis of the n-hexane extract by GC-MS led to the identification of twenty-six components by comparison of their mass spectra with GC-MS library data. A novel quinolone alkaloid, vitiquinolone (5) together with eight known compounds viz. β-Amyrin acetate (1), n-octacosanol (2), β-Amyrin (3), stigmasterol (4), xanthyletin (6), alloxanthoxyletin (7), xanthoxyletin (8) and betulinic acid (9) were isolated from chloroform extract by column chromatog

Метод газовой хроматографии для количественного определения остаточных растворителей в наноформуляциях.

Описано разработку и проверку метода газовой хроматографии, который является чувствительным, быстрым и специфичным для оценки 19 распространенных растворителей класса 2 и класса 3, часто используемых в формулировке наномедицины. Проверка метода проводилась с использованием системы газовой хроматографии PerkinElmer с детектированием искровой ионизации и колонки Elite 624 Crossbond 6% цианопропилфенил-94% диметилполисилоксана или DB-Fatwax-Ultra Inert с гелием в качестве носителя. Оценены характеристики валидации, такие как линейность, восстановление при добавлении, точность метода, специфичност

Совпадение в аннотации оригинала
The development and validation of a sensitive, rapid, and specific gas chromatography method for the evaluation of 19 common Class 2 and Class 3 solvents frequently used in nanomedicine formulation is described. Method validation was performed using PerkinElmer's headspace gas chromatograph system with flame ionization detection and an Elite 624 Crossbond 6%…

Plastitar and pyroplastics as emerging vectors of coastal pollution: Chemical identification from Panjang Island (Java Sea) and Palm Beach, Florida.

Novel plastic-derived materials such as plastiglomerates, pyroplastics, and plastitar have emerged as persistent pollutants in coastal envir … derived from thermally affected plastic debris or embedded in tar matrices. Gas chromatography with flame ionization detection (GC-FID) analysis of Panjang Island samples, supplemented by comprehensive two-dimensional GC × GC-FID for selected specimens, revealed that the oil residue in the plastitar samples is dominated by n-alkanes (n-C16 to n-C37) and contains i …

Development and validation of a method for determinion of organophosphorus flame retardant di-ester and hydroxylated metabolites in human urine.

BACKGROUND: As biomarkers for assessing human exposure to organophosphate flame retardants (OPFRs), the accurate measurement of urinary metabolites of OPFRs (mOPFRs) is critical for evaluating their health impacts. RESULTS: We established a high-throughput liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique for the concurrent quantification of 14 mOPFRs in human urine, including diesters and hydroxylated metabolites. Urine samples were processed via solid-phase extraction, eluted with 2% ammoniated methanol solution, concentrated by nitrogen stream, and finally reconstituted i

Optimized extraction of Pinus taeda knotwood sawmill residues as source of antifungal compounds.

In Uruguay, Pinus taeda is the dominant conifer in industrial plantations, generating large volumes of knot-containing offcuts during processing. These residues are highly enriched in extractives, offering opportunities for valorization within a circular bioeconomy. This study examined the recovery of bioactive compounds from P. taeda knotwood through ethanol extraction, process optimization, Gas Chromatography coupled with Mass Spectrometry and Flame Ionization Detection (GC-MS/FID) analysis, and antifungal evaluation. The effects of extraction temperature, ethanol concentration, and liquid-s…

Methanol-Related Fatalities in Jeddah, Saudi Arabia: A 5-Year Post-Mortem Multi-Matrix Study.

Although alcohol consumption is prohibited in Saudi Arabia, methanol poisoning outbreaks continue to occur, largely through surrogate or non … stric contents, and selected tissues were quantified using a validated headspace gas chromatography-flame ionization detection method. Decedents were aged 18-73 years (median, 34.5 years), with a marked predominance of young-to-middle-aged men. PMI ranged 1-15 days (median, 2 days), and evidence of putrefaction was present in approximately one-third of the cases. …

Carcinogenic risk in printing industry: A comparative assessment of occupational exposure to solvents across offset, flexographic, and gravure techniques.

Volatile organic compounds such as benzene, toluene, ethylbenzene, and xylene, with ethyl acetate, propanol, and ethanol, are commonly used … (1501 for BTEX, 1400 for alcohols, and 1457 for ethyl acetate) with analysis by gas chromatography-flame ionization detection (GC-FID). The USEPA risk assessment model was employed to calculate Lifetime Cancer Risk (LCR) and Hazard Quotient (HQ) for each chemical. The study revealed significant differences in chemical exposure risks among printing techniques. Off …

[Determination of isopropyl acetate, tert-butyl acetate and sec-butyl acetate in workplace air by solvent desorption-gas chromatography].

Objective: To establish a method for the determination of isopropyl acetate, tert-butyl acetate and sec-butyl acetate in the air of workplace by gas chromatography. Methods: In November 2023, the air in the workplace was collected using activated carbon tubes for isopropyl acetate, tert-butyl acetate and sec-butyl acetate. The samples were desorbed with carbon disulfide, separated on a capillary chromatographic column, detected by a hydrogen flame ionization detector (FID), and the detection limits, precision, desorption rates, etc. of the method were analyzed. Results: The linear ranges for t…

Fatty Acid Profile and Hazard Index of Ready-to-Eat Foods Available in the Market: A Risk Survey.

BACKGROUND: Dietary fat is of necessary macronutrients for body health. According to the guidelines, up to 10% of calories can be supplied b … were purchased from local markets. The fatty acid profile was determined using a gas chromatograph-flame ionization detector. RESULTS: According to our results, trans fats were found at very low levels in the products. The amount of saturated and trans fats increased by increasing the concentration of meat. In comparison, the most concentration of unsaturated fa …

Integrating gas-chromatographical analyses with nuclear-magnetic-resonance spectroscopy to elucidate anti-microbial profile of oleoresins isolated from Rauvolfia serpentina seeds by supercritical-(CO2)-fluid extraction.

Rauvolfia serpentina (L.) Benth. Ex Kurz is a greatly appreciated medicinal plant, well-known for its therapeutic benefits in traditional medicine, particularly in Ayurveda, where the roots and whole plant are used to treat a variety of ailments. However, studies focusing on R. serpentina seeds are relatively scarce. Hence, the present study provides a novel approach by analysing the seed oil of R. serpentina extracted using the supercritical-carbon dioxide-fluid-extraction (SCFE) technique. The research employed advanced analytical methods including gas-chromatography with flame ionization de…

Continuous Intravenous Nimodipine Infusion With Ethanol as Carrier in Aneurysmal Subarachnoid Hemorrhage Does Not Result in Measurable Cerebral Ethanol Levels.

An unimpaired neurological evaluation is essential for detecting delayed cerebral ischemia (DCI) in aneurysmal subarachnoid hemorrhage (aSAH … e ethanol neuronal exposure. Ethanol concentrations were determined by headspace gas chromatography-flame ionization detection in plasma and CSF and we set out brain parenchyma measurement using cerebral microdialysis, in 10 aSAH patients. In each compartment four samples were taken over a 6-hour interval during steady-state intravenous nimodipine infusion at four …

A method for simultaneously determining both the inhalable fraction and vapor concentration to assess worker exposure to tri-n-butyl phosphate.

OBJECTIVES: This study aimed to develop a personal exposure measurement method that concurrently determines both the inhalable fraction and vapor concentration of tri-n-butyl phosphate (TBP). METHODS: A personal sampler, the IFV Pro, equipped with a glass-fiber filter (GFF) and a Chromosorb 106 adsorption tube was used. Postsampling, TBP was extracted or desorbed separately from the GFF and Chromosorb 106 using dichloromethane containing tri-n-amyl phosphate as an internal standard. The solutions obtained were analyzed via gas chromatography with a flame ionization detector. The evaluation pa…

Oxidative stress induction by essential oil from Piper alatipetiolatum (Piperaceae) triggers lethality in the larvae of Culex quinquefasciatus (Diptera: Culicidae).

Culex quinquefasciatus is the main vector of lymphatic filariasis in Brazil, which present resistance to commercial insecticides. Nowadays, … 0.1%, analysed by gas chromatography coupled with spectrometry and gas chromatography coupled with flame ionization detector (GC-MS and GC-FID), and evaluated against Cx. quinquefasciatus larvae. Reactive Oxygen and Nitrogen Species (RONS), Catalase (CAT), glutathione-S-transferase (GST), acetylcholinesterase (AChE), and Thiol levels were used as oxidative stress …