Gas Chromatography Research Articles

Hydrogen, Methane, Brine Flow Behavior, and Saturation in Sandstone Cores During H2 and CH4 Injection and Displacement

Large-scale underground hydrogen storage (UHS) is a critical component in the emerging hydrogen economy. Knowledge of multiphase flow behavior involving hydrogen in storage reservoir formations is crucial to characterizing hydrogen transport properties and essential for the deliverability and storage operations of UHS. There are still many gaps in fully understanding hydrogen–methane–brine multiphase phase flow that require further investigation. In this work, H2 and CH4 were injected through brine-saturated sandstone cores using a tri-axial core holder system fitted with flow rate meters and pressure transducers, while the effluent gas concentrations were analyzed using an online micro gas chromatograph. Brine displacement, permeability, and gas breakthrough curves were measured. We studied the flow behavior of hydrogen and methane in sandstone cores through testing brine displacement by gas injection and comparing the hydrogen displacement of methane with the methane displacement of hydrogen. We also tested the differences between horizontal and vertical flow in brine displacement. The results showed that brine displacement was more efficient in a core with higher permeability and porosity, resulting in a higher initial gas saturation. A higher gas injection rate brought about faster gas breakthrough measured by pore volume and sharper concentration curves. Hydrogen did not exhibit abnormal flow in the sandstone when the flow was horizontal and downward vertical. Gas overriding was observed in brine displacements when the flow was horizontal, with hydrogen showing this behavior more profoundly compared to methane. Downward vertical gas injection induced higher efficiency brine displacement compared to horizontal displacement and resulted in a higher initial gas saturation in the sandstone cores. These findings address critical knowledge gaps regarding gas flow patterns and displacement behaviors during hydrogen injection and recovery phases in UHS facilities using methane as the cushion gas. The insights from this research offer valuable guidance for optimizing UHS systems, ensuring operational efficiency, and advancing sustainable energy solutions in alignment with decarbonization goals.

Validation of the QuEChERSER Method for 245 Pesticides and Environmental Contaminants in Barley and Hemp by Low-Pressure GC: Comparison of Triple Quadrupole MS/MS and Orbitrap HRMS for Qualitative and Quantitative Analysis.

Monitoring labs are a fundamental link in the food safety chain, and regulatory demands in a competitive economy call for analytical methods that are simpler, faster, more rugged, and broader in scope. The QuEChERSER mega-method introduced in 2021 meets these monitoring needs, which includes high sample throughput, automated cleanup of extracts, and fast low-pressure gas chromatography (LPGC). The goal of this work was to extend the QuEChERSER method to additional matrices and more analytes using LPGC, including comparison of the analytical performances of two different mass spectrometric (MS) analyzers: triple quadrupole tandem MS/MS and orbital ion trap (orbitrap) high-resolution (HR)MS. The QuEChERSER mega-method was validated for 245 pesticides and environmental contaminants in barley grains and hemp pellets using automated instrument top sample preparation (ITSP) coupled with LPGC-MS/MS or LPGC-HRMS (orbitrap). Targeted MS/MS detection proved to be more sensitive than orbitrap using full data acquisition, leading to lower limits of quantification (LOQs) with more analytes yielding acceptable recoveries (70-120%) and repeatabilities (RSDs <20%). In barley, 89% of the compounds met validation criteria in MS/MS and 74% in HRMS, which in hemp were 81% and 66%, respectively. Qualitatively, orbitrap HRMS yielded 1% false positives compared to 3-4% in MS/MS, but due to the higher LOQs, the rates of false negatives were 14-17% in orbitrap vs. 6-10% in MS/MS for the different matrices. The QuEChERSER mega-method including ITSP+LPGC coupled with MS/MS or orbitrap analysis is a robust approach for multiple applications. In the comparison, MS/MS outperformed the orbitrap in terms of sensitivity, but the orbitrap advantages of easier method development, greater selectivity, and possibility for nontargeted/retrospective analysis permit even broader expansion of analytical scope in the future. ITSP+LPGC- MS/MS or HRMS (orbitrap) analysis as part of the QuEChERSER mega-method is a useful and efficient way to monitor for contaminants in foods.

Phytochemical profiling of metabolites in commercial sugarcane (Saccharum officinarum L.) varieties that confer resistance to feeding of yellow sugarcane aphid (YSA) (Sipha flava) by using gas chromatography Mass Spectrometry (GC-MS) metabolomics approach

Phytochemical profiling of metabolites in commercial sugarcane (Saccharum officinarum L.) varieties that confer resistance to feeding of yellow sugarcane aphid (YSA) (Sipha flava) by using gas chromatography Mass Spectrometry (GC-MS) metabolomics approach

Essential oils as natural sources for the control of Botrytis cinerea: Chemical composition and antifungal effect

The essential oils of cinnamon, clove, bergamot, lemongrass, citronella, rosemary, basil and lemongrass were extracted by hydrodistillation, had their composition determined by gas chromatography coupled with mass spectrometry and were investigated for their potential to restrict Botrytis cinerea cultivar in vitro, a fungus responsible for the gray mold disease that mainly attacks strawberry plants. Their composition was then correlated chemometrically to identify likely compounds that were related to the observed inhibition effects. Five essential oils demonstrated an inhibitory effect on Botrytis cinerea, through the well diffusion method, with the control plate being the plate without the addition of essential oil. Among these, clove, cinnamon and lemongrass showed the greatest action with the lowest inhibitory concentrations (0.85 mg/mL). The best fungicidal effects were for the essential oil of cinnamon (0.85 mg/mL), clove (1.27 mg/mL) and aloysia (2.12 mg/mL). The main correlated compounds were cinnamaldehyde, eugenol, β-citral and citronellal. Through the analysis of the main components, it is observed that lemongrass essential oil is closer to clove essential oil and, subsequently, to aloysia essential oil, having some compounds in common, among them limonene and citral.

Rapid Determination of Methamphetamine, Methylenedioxymethamphetamine, Methadone, Ketamine, Cocaine, and New Psychoactive Substances in Urine Samples Using Comprehensive Two-Dimensional Gas Chromatography.

Background/Objectives: This study evaluates the applicability of a comprehensive two-dimensional gas chromatography-flame ionisation detection (GC×GC-FID) approach for the simultaneous determination of 12 underivatised psychoactive drugs, including new psychoactive substances, that comprised of amphetamine, methamphetamine, mephedrone, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, α-pyrrolidinovalerophenone, n-ethylpentylone (ephylone), norketamine, ketamine, 3,4-methylenedioxypyrovalerone, methadone, and cocaine. Methods: Separation was effected using a non-polar first dimension (1D) and a polar second dimension (2D) column, demonstrating an improved separation of drug compounds compared to a polar/non-polar column configuration. Interference-free baseline separation of all psychoactive compounds in a urine matrix was achieved within 8 min. The GC×GC-FID method was validated according to the guidelines defined by Standard Practices for Method Validation in Forensic Toxicology. Results: The calibration curves for the 12 psychoactive drugs were well correlated (r2 > 0.99) within the concentration ranges of 50-1500 ng mL-1. Detection limits of 10-20 ng mL-1 were obtained, and good repeatability and reproducibility (CV < 11.4%) were attained for retention times and peak areas. Method recoveries for the small-scale solvent extraction procedure ranged from 96.9 to 114.5%, and bias was between -3.1% and 14.5%. Conclusions: The validated approach was successfully applied for the determination of these illicit compounds in spiked urine samples of different concentrations, highlighting its potential for rapid forensic drug screening.

Serial Re-Pitching of Yeast Impacts Final Flavor Profiles of Commercial Beer

The aroma-active compounds produced by Saccharomyces cerevisiae during the fermentation of wort are key to the unique aroma and flavour profiles of beer. In commercial fermentations, there is batch-to-batch variation depending on yeast “brewing fitness” or the health of the yeast, but how does yeast health impact fermentation performance and metabolite production during fermentation? To address this, daily samples were collected from three full-scale commercial fermentations. The specific gravity was measured immediately, and samples were collected for carbohydrate analysis by High-Performance Liquid Chromatography and volatile compound analysis by Head-Space Gas Chromatography Mass Spectrometry (HS-GC-MS). Acetate esters (3), medium-chain fatty acid ethyl esters (7), hop-derived compounds (3), and an off-flavour (1) were detected and identified, and their relative signal was recorded for each sample. While there did not appear to be an effect of generational age on the duration of fermentation, age, in terms of the number of generations from serial re-pitching, impacted the ratios of volatile compounds. This difference in ratios was observed as early as Day 2, resulting in a difference in the volatile compound profiles of finished beers, therefore resulting in inconsistency in the product. This is important knowledge for brewers as generational age must be considered when fermenting high-quality, consistent products and monitoring fermentation progress/duration may not be enough to determine the ability of yeast to produce balanced flavour profiles.

Detection of volatile organic compounds in soils (literature review)

Volatile organic compounds (VOC) are major environmental pollutants. Due to their high mobility, they penetrate into all environmental objects, pose an environmental threat and health risks. Getting into the soil, they deteriorate its quality. VOC content requires reliable control. There is presented a review of the literature, including methods of the US Environmental Protection Agency, and regulatory and methodological documents of the Russian Federation regulating methods of selection, storage, preparation and analysis of soil samples for VOC content. The dominant place among methods for monitoring for VOCs belongs to gas chromatography with various types of detectors. For multicomponent analysis of complex objects, gas chromatography with mass selective detection is used due to the wide capabilities provided by the mass detector. A universal mass spectrometry method used in analytical laboratories is electron impact ionization mass spectrometry. For research purposes, modern highly sensitive methods are used – mass spectrometry based on the proton transfer reaction PTR-MS, ion trap mass spectrometry PIT-MS, negative ion ionization mass spectrometry NI-PT-CIMS, time-of-flight mass spectrometry of the transfer reaction proton PTR-TOF-MS. The collection and storage of samples for VOC analysis requires compliance with regulations to prevent both loss of analytes and sample contamination. Sample preparation includes methods such as vacuum and azeotropic distillation, thermal desorption, liquid extraction, various options for static and dynamic headspace analysis.

Methods for Detection, Extraction, Purification, and Characterization of Exopolysaccharides of Lactic Acid Bacteria-A Systematic Review.

Exopolysaccharides (EPSs) are large-molecular-weight, complex carbohydrate molecules and extracellularly secreted bio-polymers released by many microorganisms, including lactic acid bacteria (LAB). LAB are well known for their ability to produce a wide range of EPSs, which has received major attention. LAB-EPSs have the potential to improve health, and their applications are in the food and pharmaceutical industries. Several methods have been developed and optimized in recent years for producing, extracting, purifying, and characterizing LAB-produced EPSs. The simplest method of evaluating the production of EPSs is to observe morphological features, such as ropy and mucoid appearances of colonies. Ethanol precipitation is widely used to extract the EPSs from the cell-free supernatant and is generally purified using dialysis. The most commonly used method to quantify the carbohydrate content is phenol-sulfuric acid. The structural characteristics of EPSs are identified via Fourier transform infrared, nuclear magnetic resonance, and X-ray diffraction spectroscopy. The molecular weight and composition of monosaccharides are determined through size-exclusion chromatography, thin-layer chromatography, gas chromatography, and high-performance liquid chromatography. The surface morphology of EPSs is observed via scanning electron microscopy and atomic force microscopy, whereas thermal characteristics are determined through thermogravimetry analysis, derivative thermogravimetry, and differential scanning calorimetry. In the present review, we discuss the different existing methods used for the detailed study of LAB-produced EPSs, which provide a comprehensive guide on LAB-EPS preparation, critically evaluating methods, addressing knowledge gaps and key challenges, and offering solutions to enhance reproducibility, scalability, and support for both research and industrial applications.

Characterization of Fume Suppression Effect and Performance of SBS-Modified Asphalt with Deodorant

SBS-modified asphalt produces a large number of hazardous fumes in the preparation process, which severely endangers health and causes environmental pollution. This paper details the design of a fume generation and collection device for asphalt and proposed a comprehensive method for analyzing fume composition. Two deodorants were incorporated into SBS-modified asphalt to mitigate the hazards of the original hazardous emissions. Then, ultraviolet–visible spectrophotometry, gas chromatography–mass spectrometry, and Fourier-transform infrared spectroscopy were combined to analyze the main component differences between asphalt fumes before and after adding deodorant, and to specify the mechanism of action of deodorants on hazardous fumes and SBS-modified asphalt. Finally, the road performance, including the physical and rheological properties of SBS-modified asphalt blended with deodorant, was evaluated. The results indicated that both deodorizers were effective in reducing the emission of hazardous substances in the fumes of SBS-modified asphalt, and no new hazardous substances were generated. Under hot mixing conditions, the addition of 0.3% of deodorant A (high boiling point ester) was effective in reducing the emission of volatile organic compounds (VOCs) by up to 41.7%, while the reduction in benzene congeners reached at least 50%. On the other hand, 1% of deodorant B (silica–magnesium compounds) reduced the emissions of VOCs and benzene congeners by 36% and 20–42%, respectively, under the same conditions. Furthermore, the addition of deodorant did not affect the original road performance, and even improved the rheological properties to a certain extent, which was conducive to the application of deodorant in pavement engineering.

Separation and characterization of sweet compounds in Baijiu by molecular distillation combined with molecular sensory science

Sweetness is a crucial taste component in Baijiu. However, comprehensive research on the sweetness of Baijiu remains limited, and traditional methods for flavor analysis are not well-suited for identifying the sweet compounds. To address this, a multi-stage molecular distillation method, combined with molecular sensory science, was developed to more effectively and scientifically analyze the key sweet compounds in Baijiu. The recovery rates of samples and compounds were 93.8 % ∼ 98.3 % and 81.6 % ∼ 118.3 %. 15 important compounds with a taste dilution factor (TD) value ≥64 were identified through gas chromatography–mass spectrometry (GC–MS) combined with taste dilution analysis (TDA). By calculating their taste activity values (TAV), 10 primary sweet compounds with TAV ≥1 were determined. Further taste recombination and omission experiments confirmed that ethyl hexanoate, ethyl heptanoate, ethyl octanoate, ethyl 2-methylbutyrate, 1-butanol, phenethyl alcohol, and ethyl acetate contribute significantly to Baijiu's sweetness and are identified as the key sweet compounds.

Identification of Floral Fragrance Components in 20 Intersectional Hybrids of Paeonia in Luoyang Region

ABSTRACTIntersectional hybrids of Paeonia (Paeonia Itoh hybrids) have rich colours and strong fragrance, combining the advantages of sect. Moutan and sect. Paeonia, and have great economic value and development potential. However, there have been few studies on the floral fragrance components of intersectional hybrids of Paeonia. In this study, the types and contents of volatile components of 20 intersectional hybrids of Paeonia were conducted. A total of 53 floral volatiles were identified though gas chromatography–mass spectrometry (GC–MS) analysis, with linalool, nonanal and phenylethyl alcohol as the main floral components. Based on the compound contents and odour activity values (OAVs) analysis, the 20 cultivars were classified into four aroma types: a floral scent, a fresh floral scent, a floral with spicy scent and a fruity scent. ‘Magical Mystery Tour’ had the highest volatile compound contents and OAVs, and had potential for exploitation. This study provided a theoretical reference for the selection of parents for flower fragrance breeding of Paeonia Itoh hybrids.

Increased Informativeness of the Input Signal in Gas Chromatography when Using a Syringe to Introduce the Adsorbed Substance into a Column with No Adsorbent

Increased Informativeness of the Input Signal in Gas Chromatography when Using a Syringe to Introduce the Adsorbed Substance into a Column with No Adsorbent

New eco-friendly succinimide linseed oil resin: synthesis, characterization, DFT and docking studies for surface coating

Purpose The purpose of this study is to develop a new protective coating formulation for industrial use, using new eco-friendly succinimide linseed oil resin. Design/methodology/approach Epoxidized linseed oil and N-(4-hydroxy phenyl) succinimide are reacted to create succinimide-modified epoxy (SIE) compounds. The synthesized compound was confirmed by different analyses, gas chromatography, Fourier transform infrared, proton nuclear magnetic resonance and scanning electron microscopy. The prepared compound has been blended with a primer paint formulation, then their physical and mechanical properties have been studied. Density function theory is used to calculate Frontier molecular orbital including highest occupied molecular orbital and least unoccupied molecular orbital to indicate the charge transfer from molecule to biological media and molecular electrostatic potential map was used to indicate the chemically reactive zone suitable for drug action. Findings The results of the paint formulation confirmed their best performance and provided good mechanical properties and high chemical and corrosion resistance. Research limitations/implications Resin compounds are the most used antimicrobial additives. Other functionalities of these compounds, such as corrosion inhibitors, might be studied to see if they are suited for these applications. Practical implications Because of the efficiency of the SIE when incorporated with primer, paint against microbial has also been examined in silico using the docking study which contributed to the analysis of their protein binding. This type of epoxy compound is environmentally friendly and can be used as a biocide with different paint formulations. As a result, paint compositions including this compound as additives can be used as dual-purpose paint and for a variety of industrial applications. Originality/value This research demonstrates how a low-cost paint composition based on synthesized SIE compounds may be used as a dual-function paint for industrial use.

In Situ Synthesis of Hypercrosslinked Polymer as Stationary Phase for Capillary Gas Chromatography

Hypercrosslinked polymers (HCPs) constructed by the Friedel–Crafts alkylation reaction of aromatic compounds have emerged as a new class of porous materials with unique merit. Herein, a HCP named HCP-TPB was coated onto a capillary column through in situ synthesis. The prepared column exhibited a nonpolar nature, and the column efficiency for n-dodecane was 3003 plates m−1. Moreover, the relative standard deviations of retention time and peak area for six replicate injections of the C3–C6 were lower than 0.1% and 1.5%, respectively. The results of this study showed that it is very promising to utilize HCPs as stationary phases for the separation of C3–C6.

Preliminary phase results of GC-MS analysis and cytotoxic activity of Argemone mexicana leaves methanol extract against MCF-7 cell lines

Argemone mexicana leaves (AML) contain a variety of bioactive components such as fatty acids, amino acids, phenolics and alkaloids, including Berberine, Isoquinoline, Scoulerine, Stylopine, Thalifone, Benzylisoquinolines, Protopine, and Tetrahydroberberine. This study aimed to examine the gas chromatography and mass spectrometry (GC-MS) analysis of AML extract and its cytotoxic activity on MCF-7 cell lines to identify an alternative source for anticancer treatment. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was utilized to assess the viability of AML extract-treated cells, while the apoptotic assay involved Acridine orange staining to determine the mode of cell death based on morphological and nuclear fragmentation. The GC-MS analysis was used to identify the biologically active compounds. The results showed that the percentage of cell viability after AML extract treatment ranged from 28.50% to 64.28% for concentrations of 1000 to 125 μg/ml (IC50 = 258.87 μg/ml). Statistical analysis revealed a significant difference in cell viability (p &lt; 0.05). Exposure of cells to AML extract stimulated apoptosis through membrane blebbing, cell shrinkage, cytoplasm condensation, and nuclear fragmentation. Forty-one compounds were identified by GC-MS in the AML extract. Based on the peak area, some major compounds included n-Hexadecanoic acid (palmitic acid), 9,12-Octadecadienoic acid (Z, Z)-, Phytol, 9,12,15-Octadecatrienoic acid (Z, Z, Z)-, and 1-methyl piperidine. In conclusion, the bioactive compounds are apparently responsible for the cytotoxic effects of the AML extract, and the in-vitro results highlight the extract’s potential as a source of natural anticancer drugs. However, further investigation is necessary to confirm this.

Application of 1-octanol in the extraction and GC-FID analysis of volatile organic compounds produced in biogas and biohydrogen processes

Information about the volatile organic compounds generated in biogas and hydrogen production bioreactors is essential to elucidate the metabolic routes and varying yields of CH4 and H2 processes. In this work, the determination of 12 compounds (acetone, methanol, ethanol, 1-propanol, 1-butanol, and acetic, propanoic, butyric, isovaleric, valeric, caproic, and lactic acids) was performed by gas chromatography, after a vortex-assisted liquid–liquid microextraction (VALLME) procedure using 1.2 mL of crude sample and 400 µL of 1-octanol. Optimization of the separation process was performed, considering the solvent viscosity. The analytical curves were validated using ANOVA, demonstrating satisfactory precision and accuracy. Selectivity was confirmed by GC–MS analysis, which allowed the detection of glycerol, 1,3-propanediol, and 1,3-butanediol in some samples. Methanol levels exceeded the upper limit of quantification, with acetic acid and ethanol being the predominant compounds in the analyzed reactors. An additional investigation was conducted to assess potential interferences for lactic acid. The developed method employs a biodegradable extraction solvent, without any need for a dispersing solvent, and involves a single chromatographic run, without any derivatization steps.

Immunization of male BALB/c and C57BL/6 mice similar modulates chemical signals detected in both chromatographic and behavioral tests

The odor plays a key role in communication between animals and the choice of a mate. The odor of urine of males becomes less attractive to mature females after infection or activation of the immune system. The development of the immune response in the early stages is related with the production of both pro-inflammatory and anti-inflammatory cytokines. To investigate the chemical basis of the observed differences and examine the influence of female interactions with the odor of antigen-treated males, we immunized males of inbred BALB/c (Th1) and C57BL/6 (Th2) mice with hemocyanin (KLH). For females of both tested strains, the attraction of the odor of male urine collected 3 days after immunization was lower compared with the odor of control males. Herewith, BALB/c females sniffed the urine of immunized males less frequently, and C57BL/6 females demonstrated a shorter duration of grooming in olfactory tests with urine of immunized males. The altered response of females to the odor of male urine collected on day 3 after KLH injection matched with antigen-induced modulation of relative levels of volatile organic compounds (VOCs) detected in urine samples by gas chromatography and mass spectroscopy (GC-MS). In males of both strains, after KLH injection, an increase in the content of nonanal, benzothiazole, as well as 2-sec-butyl-4,5-dihydrothiazole, and [1,4,5]-oxadithiepane was shown. At the same time, no compounds were found, the content of which changes in different directions in the urine of males after immunization, depending on the strain of the animal.

HS-SPME-GC-MS combined with relative odor activity value identify the key aroma components of flowery and fruity aroma in different types of GABA tea

Anaerobic processing is a crucial factor influencing the formation of flavor quality in Gamma-aminobutyric acid (GABA) tea. In this study, headspace solid-phase microextraction combined with gas chromatography and mass spectrometry was employed to explore the flavor characteristics of different types of GABA tea. We utilized multivariate analyses to identify at least 146 volatile components (VOCs) across 12 functional groups in the GABA tea samples via principal component analysis (PCA). At least 40 differential VOCs were screened from the GABA tea samples via orthogonal partial least squares-discriminant analysis. Subsequently, a minimum of four VOCs were identified in the GABA tea samples via the Pearson correlation coefficient combined with relative odor activity values as potential markers for flowery and fruity aromas, clarifying the impact of the VOCs on these characteristics. The results of this study provide a theoretical basis for understanding the formation of flowery and fruity flavor characteristics in GABA tea.

Complete replacement of fishmeal with unconventional animal protein sources: A comparative study of the effects of use of mealworm, earthworm and zooplankton on growth parameters, fatty acid composition and sensory profile rainbow trout

The global trend in aquaculture is to replace fishmeal with an alternative and sustainable source of protein for fish farming. As a result, some species of invertebrates have found a place in aquaculture as a rich source of protein and a promising substitute for fishmeal. This study aimed to investigate the effects of alternative protein sources on the growth parameters of rainbow trout (Oncorhynchus mykiss) as well as the fatty acid profile and the sensory quality of the fish fillets. The gas chromatography technique with a flame ionization detector was used to determine the fatty acid composition of the rainbow trout fillets, while different equations were used to determine the growth parameters and the hepatosomatic index. The sensory evaluation of the rainbow trout fillet was determined by a descriptive sensory analysis, a quality assessment and a consumer acceptance test. The replacement of fishmeal by mealworms (MWD) and earthworms (EWD) resulted in a positive effect on growth parameters, feed conversion, and hepatosomatic index (HSI) values. The mortallity of the rainbow trout fed with the experimental diets was less than 28 %. The eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) content of the trout fillets decreased with the inclusion of MWD (1.34 and 5.20 %, respectively) and EWD (1.74 and 6.41 %, respectively) in the trout diet. Feeding rainbow trout with MWD and EWD caused a decrease in the n-3/n-6 ratio compared to FMD (0.32 and 0.34, respectively vs. 0.56), whereas the addition of ZOD resulted in the increase of the n-3/n-6 ratio (0.67). The samples of fillets of trout fed with MWD and EWD belonged to the "very good" level of average sensory quality, while the fillets of trout fed with zooplankton were in the "good" quality range. Regarding acceptability by consumers all rainbow trout fillets shown good consumer acceptance.

Pollution investigation of wintertime VOCs in the coastal atmosphere of the Yellow Sea: Insights from on-line photoionization-induced CI-TOFMS.

Volatile Organic Compounds (VOCs) are pivotal in tropospheric atmospheric chemistry, significantly impacting the formation of photochemical smog, fine particle pollution, and the atmospheric oxidizing potential, all of which affect air quality. Chemical ionization time-of-flight mass spectrometry, renowned for its exceptional sensitivity, precision, and swift response time, has proven to be exceptionally effective for real-time VOCs monitoring. In this study, a custom-built photoionization-induced CI-TOFMS was deployed to individually detect 116 VOCs standard gases specified by the United States Environmental Protection Agency, quantifying their responses and establishing a distinctive mass spectrogram database. A 12-day comparative analysis with online gas chromatography coupled with a flame ionization detector and mass spectrometer demonstrated the high reliability of the PICI-TOFMS, confirming its effectiveness for field VOCs monitoring. During two months of stationary monitoring, the PICI-TOFMS could further refine the timing of pollution events with high temporal resolution and identified four distinct air pollution episodes, including local emissions, coal burning, sand and dust transport and festival-related pollution. Employing a Hysplit model, the Concentration Weighted Trajectory model, and a source apportionment method based on tracer gases, the air trajectories were calculated and contributions from different potential source areas were quantified. Our findings reveal that transport was the main contributor to pollution in December 2022, while burning was the primary source in January 2023. This study refines our understanding of the dynamics of air pollution, providing valuable insights into the temporal and spatial distribution of VOCs and their sources.