Search Results (3,973)

Volatile organic compounds (VOCs) emitted from human skin are promising biomarkers for non-invasive health assessment and disease diagnosis. However, efficient collection and sensitive analytical methods for skin VOCs remain challenging. We developed a method for measuring ethanol, acetaldehyde, and acetone from palmar skin using glass cup aqueous sampling followed by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Compounds were extracted using a carboxen/polydimethylsiloxane fiber by HS-SPME and separated using a DB-1 capillary column within 5 min. The HS-SPME/GC-MS method showed linearity (5–1000 ng/mL, r ≥ 0.990) with detection limits of 0.56, 1.01, and 0.15 ng/mL for ethanol, acetaldehyde, and acetone, respectively. Intra-day and inter-day precision were ≤9.3% and ≤9.7%, with accuracy ranged of 94–110%. Five-minute palm contact with water caused VOC release to increase linearly, and samples remained stable for 24 h at −20 °C. Following ingestion of a 500 mL alcoholic beverage (5% ethanol), ethanol and acetaldehyde emissions peaked at 95 and 24 ng/cm²/min after 1 h, while acetone gradually increased to 1.3 ng/cm²/min after 6 h. This simple, rapid method enables practical assessment of skin VOCs for health monitoring and environmental exposure evaluation. Full article

To characterize the key odorants and elucidate the flavor profiles of compound fermented beverages after fermentation, single-compound fermented beverages (GW, AW) and a compound fermented beverage (CW) were prepared using Italian Riesling grapes and SirPrize apples as raw materials. The flavor and metabolite profiles were systematically analyzed by integrating flavoromics (comprehensive two-dimensional gas chromatography–time-of-flight mass spectrometry, GC × GC–TOF MS) and metabolomics (LC–MS/MS). The results demonstrated that CW exhibited the most favorable acid/reducing sugars (2.18), imparting a drier taste and superior stability. Compounds with relative odor activity values (rOAV) greater than 1—including 3-methyl-1-butyl acetate, ethyl hexanoate, ethyl butanoate, and ethyl octanoate—collectively contributed prominent fruity, floral, and sweet aromas to all three wine types. Ethyl decanoate provided an additional distinctive traditional fruity note specifically to AW, while 1-octen-3-ol contributed a mushroom-like aroma to both GW and CW. Moreover, 3-methylbutanal, 4-ethyl-2-methoxyphenol, and ethyl 3-methylbutanoate added additional significant aroma contributions to CW, imparting floral, clove-like, and fruity notes, respectively. Notably, ethyl hexanoate (fruity aroma) exhibited a remarkably high rOAV of 27.43 in CW, significantly surpassing its levels in the single-substrate fermentations. Lipid metabolism and the phenylpropanoid pathway were significantly activated in CW, facilitating the coordinated synthesis of esters and phenolic compounds. Sensory attribute network analysis further confirmed that CW possessed more pronounced “sweet”, “fruity”, and “floral” characteristics. Correlation analysis revealed significant relationships between volatile organic compounds (VOCs) and total soluble solids (TS), titratable acidity (TA), the TA/TS ratio, and metabolite levels, underscoring the close connections among physicochemical properties, precursor/intermediate metabolites, and flavor formation. Comprehensive analysis of non-volatile metabolites and flavor-associated VOCs revealed variety-specific characteristics and compounding effects, providing valuable insights for enhancing the quality of compound fermented beverages. Full article

This study systematically investigated the liposoluble components and their potential correlation with antibacterial activity in six bast fiber varieties—Apocynum venetum, Corchorus capsularis, Hibiscus cannabinus, Linum usitatissimum, Cannabis sativa, and Boehmeria nivea—using gas chromatography-mass spectrometry (GC-MS). The analysis identified a range of compounds including alkanes, phenols, sterols, esters, and triterpenoids, with notable compositional differences among the fibers. Tetracontane was predominant in A. venetum (40.39%) and H. cannabinus (22.47%), while γ-sitosterol was highest in C. capsularis (12.80%). L. usitatissimum was rich in n-hexadecanoic acid (9.16%), C. sativa in heptacosanal (8.96%), and B. nivea in both tetracontane (45.42%) and tetracosane (10.09%). Based on existing literature, components such as 2,4-di-tert-butylphenol, γ-sitosterol, n-hexadecanoic acid, lupeol, and betulin were inferred as key antibacterial constituents. A comprehensive review of reported antimicrobial activities revealed distinct antibacterial spectra and intensities across the varieties, aligning with their unique liposoluble profiles. This study provides a systematic chemical profile of bast fibers and offers a predictive assessment of their antibacterial potential. The findings lay a chemical foundation for future targeted research and development of antibacterial materials derived from specific bast fiber varieties. Full article

This study investigated the effects of three cooking methods—fragmenting process (FP), boiling treatment (BT), and high-pressure steam (HPS) treatment—on the structure and volatile compounds (VOCs) of fresh Lyophyllum decastes. The surface morphology and functional groups of L. decastes were analyzed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The VOCs in L. decastes were analyzed by comprehensive two-dimensional gas chromatography–mass spectrometry (GC×GC-MS) and gas chromatography–ion mobility spectrometry (GC-IMS). SEM results showed that HPS resulted in the most pronounced structural disruption, forming a honeycomb-like porous surface, whereas FP yielded smaller fragments with smoother surfaces. FTIR spectra indicated that none of the treatments significantly altered the characteristic functional groups. A total of 73 VOCs were identified by GC×GC-MS, including 23 hydrocarbons, 14 alcohols, 10 ketones, seven aldehydes, six ethers, three esters, two terpenes, and eight other compounds. Additionally, 22 VOCs were identified by GC-IMS, including seven alcohols, six aldehydes, five esters, three ketones, and one other compound. The four compounds benzaldehyde, benzeneacetaldehyde, (E)-2-hexen-1-ol, and 1-hexanal were detected by both methods. Among the three methods, FP induced the least structural damage and better preserved the VOCs. These results offer theoretical insights and technical support for the flavor-oriented deep processing of L. decastes. Full article

New England India Pale Ales (NEIPAs) are characterized by their hazy appearance and intense hop-derived aroma. These characteristics are central to their consumer appeal and market identity, yet the chemical drivers of these qualities remain poorly defined. This study aimed to investigate how hop profile influences NEIPA chemistry, emphasizing the role of Citra in defining volatile composition. Four profiles were evaluated: Single Hop, Citra; Multiple Hops, with Citra; Single Hop, Other; and Multiple Hops, without Citra. Volatile compounds were analyzed using a combination of sequential two-dimensional gas chromatography-mass spectrometry (GC–GC/MS) and one-dimensional gas chromatography-mass spectrometry (GC-MS). Multivariate statistical analysis was used to identify which compounds differentiated the four hop profiles. Esters, monoterpenes, and sesquiterpenes all contributed to differences across hop profiles. Inclusion of Citra hops yielded distinct volatile chemistry marked by isoamyl acetate, methyl geranate, ethyl cinnamate, and (E,E)-farnesol. By contrast, blended hop profiles showed greater chemical diversity. These findings demonstrate that hop blending alters beer chemistry beyond the sum of individual hops and identify key compounds that may serve as markers of blended versus single-hop NEIPAs. This work provides new insights into the chemical drivers of hop aroma complexity and establishes a framework for connecting hop usage, beer chemistry, and sensory outcomes. Full article

Endocrine-disrupting chemicals (EDCs) are widespread organic compounds that interfere with hormone signaling and are linked to reproductive, developmental, cardiovascular, and cancer-related health effects. Key EDCs include bisphenol-A and its analogs, phthalates, parabens, triclosan, and per-and polyfluoroalkyl substances (PFAS), which are commonly present in personal care products and plastics. Human exposure occurs via environmental exposure through ingestion, inhalation, and dermal contact, with persistent compounds such as PFAS accumulating in blood, while others are excreted in urine as free or conjugated metabolites. Accurate assessment of EDC exposure, particularly during pregnancy and early childhood, requires robust analytical methods. Liquid and gas chromatography coupled with mass spectrometry (LC-MS and GC-MS) are the most widely used techniques to date. LC-MS is favored for its sensitivity, specificity, and minimal sample preparation, whereas GC-MS provides adequate performance but often requires time-consuming derivatization. This review summarizes current LC-MS and GC-MS methodologies for multi-class EDC biomonitoring, emphasizing sample preparation, analyte coverage, and methodological strengths and limitations, providing a practical reference for human exposure studies using common biological matrices such as urine and blood. Full article

Plant-derived volatile organic compounds (VOCs) are widely used as insect attractants for population monitoring, offering an efficient and eco-friendly approach to pest management. Since thrips are the dominant pest species in alfalfa (Medicago sativa) crops, alfalfa volatiles produced in the presence of Odontothrips loti and compounds with attractive potential to both O. loti and Frankliniella occidentalis were investigated. Using gas chromatography–mass spectrometry (GC-MS), 96 VOCs were identified from seven alfalfa cultivars with varying levels of thrips resistance with and without damage by O. loti. Eleven volatiles were selected for Y-tube olfactometer assays. The semiochemical p-Menth-8-en-2-one, which was suppressed in alfalfa subject O. loti damage, significantly attracted both O. loti and F. occidentalis in Y-olfactometer bioassays; the response rates were 2.05~3.07 times compared to control (p < 0.05). Further experiments confirmed p-Menth-8-en-2-one, dispensed through PE (Polyethylene) vials, was the most effective lure material with the concentrations of 10 ng/μL. This study demonstrated that the alfalfa-derived volatile p-Menth-8-en-2-one, shows significant attraction to thrips, which can be utilized for monitoring and management of odontothrips loti and frankliniella occidentalis. Full article

The composition of the lipophilic components of Centaurea scabiosa L. has been studied. The raw material was subjected to extraction with hexane and methyl tert-butyl ether (MTBE) using both exhaustive and sequential schemes for a detailed characterization. The resulting extracts were fractionated into acidic and neutral components via treatment with alkali solutions. The acidic compounds were converted into methyl esters for subsequent gas chromatography–mass spectrometry (GC-MS) analysis, while the neutral unsaponifiable fractions were separated into groups of different polarities using column chromatography on silica gel. This approach enabled the identification of a complex profile of lipophilic substances. In the acidic fractions, aliphatic acids with chain lengths from C₁₀ to C₃₂, including unsaturated variants, were characterized. The neutral fractions revealed over compounds, encompassing n-alkanes, substantial levels of the unsaturated branched hydrocarbon squalene, and a diverse array of oxygenated terpenoids. The latter were mainly represented by highly active triterpene alcohols and ketones belonging to the ursane, oleanane, lupane, and cycloartane types. The sterol composition was dominated by β-sitosterol and accompanied by cholesterol, campesterol, stigmasterol, stigmast-7-en-3-β-ol, fucosterol, and stigmastan-3-β-ol. Bioactivity screening demonstrated that several of the obtained lipophilic extracts, particularly those of lower polarity, exhibited high inhibitory activity against the main protease of SARS-CoV-2, underscoring the potential of C. scabiosa as a valuable source of anti-coronavirus agents. Full article

Plant endophytic fungi, which colonize plant tissues and form symbiotic relationships with their hosts, are known for their high diversity and wide distribution. These fungi often influence plant growth and development through the emission of volatile organic compounds (VOCs), whose effects can extend beyond host plants to non-host species. In this study, we isolated two endophytic fungi, Trametes hirsuta RR1 and Talaromyces pinophilus RR2 from healthy rice roots. The VOCs mixtures produced by strains RR1 and RR2 were both able to promote rice growth when these strains were co-cultured with rice seedlings. Specifically, strain RR1 and RR2 increased rice shoot fresh weight by 44.22% and 26.69%, root fresh weight by 58.24% and 41.76%, shoot length by 30.35% and 25.07%, and root length by 29.11% and 4.23%, respectively. They significantly enhanced the contents of chlorophyll a and carotenoids, which increased by 18.61% and 17.04%, and by 18.73% and 31.55%, respectively. Gas chromatography–mass spectrometry (GC-MS) was applied to analyze the VOCs emitted by the two strains. The analysis successfully identified a total of 13 major compounds. Among them, at appropriate concentrations, 1-pentanol, methyl DL-2-methylbutyrate, ethylbenzene, 2-ethyl-p-xylene, ethyl benzoate and dimethyl phthalate, can promote rice growth and alter the contents of photosynthetic pigments and hydrogen peroxide to varying degrees. This study provides an important basis for the in-depth research and development of biofumigants for promoting crop growth. Full article

Tea, a worldwide prevalent beverage, is continually contaminated by pesticide residues and heavy metals, presenting considerable health concerns to consumers. Nonetheless, effective monitoring is limited by conventional detection techniques—such as gas chromatography (GC) and inductively coupled plasma mass spectrometry (ICP-MS)—which, despite their high precision, necessitate intricate pretreatment, incur substantial operational expenses, and are inadequate for swift on-site analysis. Biosensors have emerged as a viable option, addressing this gap with their exceptional sensitivity, rapid response, and ease of operation.This review rigorously evaluates recent advancements in biosensing technologies for the detection of pesticide residues and heavy metals in tea, emphasizing the mechanisms, analytical performance, and practical applicability of prominent platforms such as fluorescence, surface-enhanced Raman scattering (SERS), surface plasmon resonance (SPR), colorimetric, and electrochemical biosensors. Electrochemical and fluorescent biosensors provide the highest promise for portable, on-site use owing to their enhanced sensitivity, cost-effectiveness, and flexibility to intricate tea matrices. The paper further emphasizes upcoming techniques such multi-component detection, microfluidic integration, and AI-enhanced data processing. Biosensors provide significant potential to revolutionize tea safety monitoring, with future advancements dependent on the synergistic incorporation of sophisticated nanomaterials, intelligent microdevices, and real-time analytics across the whole “tea garden-to-cup” supply chain. Full article

The co-culture technique, mimicking natural microbial interactions, has proven to be successful at activating silent biosynthetic gene clusters (BGCs) to produce novel metabolites or enhance the yield of specific metabolites. To effectively decode induction processes, it is critical to have a comprehensive understanding of intermicrobial interactions across both volatile and non-volatile metabolomes. As part of our attempt to uncover structurally unique and biologically active natural products from mangrove endophytic fungi, Phomopsis asparagi DHS-48 was co-cultured with another mangrove fungal strain, Pestalotiopsis sp. HHL-101. The competition interaction of the two strains was investigated using morphology and scanning electron microscopy (SEM), and it was discovered that the mycelia of the DHS-48 and HHL-101 compressed and tangled with each other in the co-culture system, forming an interwoven pattern. To profile volatile-mediated chemical interactions during fungal co-culture, headspace solid-phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS) coupled with orthogonal partial least squares-discriminant analysis (OPLS-DA) was adopted. Meanwhile, non-volatile metabolites from both liquid and solid small-scale co-cultures were profiled via HPLC. Two new polyketides, named phaseolorin K (1) and pestaphthalide C (7), together with 11 known compounds (2–6, 8–13), were characterized from solid-state co-cultivation extracts of these two titled strains. Their planar structures were established by analysis of HRMS, MS/MS, and NMR spectroscopic data, while absolute configurations were assigned using ECD calculations. Co-culture feeding experiments demonstrated that DHS-48 exerts antagonistic activity against HHL-101 through altering its hyphal morphology, which mediated enhanced biosynthesis of non-volatile antimicrobial metabolites 5 and 6. Biological assays revealed that compounds 4–6 exhibited potent in vitro cytotoxicity against human cancer cell lines HeLa and HepG2, compared to the positive controls adriamycin and fluorouracil. Compound 2 moderately inhibited the proliferation of ConA-induced T and LPS-induced B murine spleen lymphocytes. Full article

Propolis is a resinous natural product produced by honeybees from plant exudates and beeswax. Its complex chemical composition varies significantly with geographical origin and seasonal factors. This study aimed to characterize the chemical composition of propolis samples collected from different regions of Latvia using gas chromatography–mass spectrometry (GC-MS). In total, 47 metabolites were identified, with chemical profiles dominated by phenolic acids and their esters—compounds typical of European propolis. Regional variations reflected differences in local vegetation, and two samples exhibited flavonoid constituents indicative of poplar-type botanical sources. The Daugavpils sample, which showed a particularly rich chemical profile, was further fractionated chromatographically, leading to the isolation of twelve metabolites: 2’,4’,6’-trihydroxy-4-methoxy dihydrochalcone, 2’,6’,4-trihydroxy-4’-methoxy dihydrochalcone, 2’,6’-dihydroxy-4,4’-dimethoxy dihydrochalcone, 2’,6’-dihydroxy-4’-methoxy dihydrochalcone, 2’,4’,6’-trihydroxy dihydrochalcone, palmitic acid, benzyl benzoate, cinnamyl cinnamate, pinostrobin, pinostrobin chalcone, pinocembrin, and pinobanksin. Given the limited prior research on Latvian propolis, this study provides valuable insights into its chemical diversity and the influence of regional flora on its composition. Full article

Given that olive oil produced in the Ionian islands has not been extensively studied, forty-seven olive oil samples of the Koroneiki olive cultivar were collected from Zakynthos, Kerkyra, Kefalonia, and Leukada, which comprise well-known islands of the Ionian Sea. The samples were subjected to analysis of volatile compounds using headspace solid-phase microextraction coupled to gas chromatography–mass spectrometry (HS-SPME/GC-MS). Based on HS-SPME/GC-MS analysis, twenty-five volatile compounds were tentatively identified and semi-quantified using the internal standard method. Volatile compounds included alcohols, aldehydes, benzene derivatives, esters, hydrocarbons, ketones, and terpenoids. The application of descriptive data analysis, such as multivariate analysis of variance (MANOVA), linear discriminant analysis (LDA), and factor analysis (FA), to the semi-quantitative data (μg/L) of the identified volatile compounds resulted in the extraction of key volatile compounds that differentiated olive oil samples of the Koroneiki olive cultivar according to geographical origin. The cross-validation method of LDA showed a prediction rate of 83.0%, whereas the variance explained by FA was approximately 69.06% (69.055%). The key volatile compounds that were associated most with the geographical origin of olive oil samples were (Z)-1,3-pentadiene, dodecane, 2,2,4,6,6-pentamethyl-heptane, 3-ethyl-1,5-octadiene, 2,4-dimethyl-heptane, 4-methyloctane, ethanol, 2-hexanol, and 3-methylbutanal, among others. The study contributes to the regional features of olive oil of the Koroneiki olive cultivar from the Ionian islands based on key volatile compounds and further supports the consecutive research of the international community regarding olive oil authentication. Full article

Gardenia black tea (GBT) is a prized Chinese scented tea, renowned for its pleasant aroma. However, the influence of repeated scenting rounds on its volatile profile remains poorly characterized. This study investigated the aroma profiles of GBT produced with zero, two, and three scenting rounds (T0, T1, T2) using sensory evaluation and Headspace Solid-Phase Microextraction–Gas Chromatography–Mass Spectrometry (HS-SPME-GC-MS). Sensory analysis revealed that GBTs (T1, T2) scored significantly higher in aroma and taste than the black tea base (T0). GC-MS analysis identified numerous volatile compounds, with esters, terpenoids, and ketones being predominant. Multivariate analysis identified 52 key volatiles (VIP > 2.0) that differentiated the tea samples. Among these, 28 compounds had odor activity values (OAVs) > 1, indicating significant sensory contributions. Ultimately, 11 volatiles, including (Z)-hex-3-enyl acetate, linalool, and (E)-hex-2-enal, were identified as the crucial basis for the characteristic fresh and floral scent of GBTs. The specific abundance levels of these compounds are hypothesized to underlie the superior, fresh, and elegant aroma of T1, compared to the slightly ripe and stuffy floral notes of T2. Therefore, it is advisable to prioritize two rounds of scenting during the production of gardenia black tea. These findings provide a theoretical foundation for optimizing the scenting process and enhancing the quality of GBT. Full article

A manganese dioxide-modified carboxylated graphene oxide (MnO₂@CGO) nanocomposite was fabricated and utilized as a solid nanosorbent for extracting six organochlorine pesticides from environmental water samples. The target compounds, Hexachlorobenzene (HCB), β-Hexachlorocyclohexane (β-HCH), Heptachlor, Aldrin, Dieldrin, and o,p-Dichlorodiphenyltrichloroethane (o,p-DDT), were determined by micro-solid phase extraction (µ-SPE) coupled with gas chromatography–mass spectrometry (GC-MS) in selective ion monitoring mode. Key experimental factors influencing the extraction performance, such as sample pH, sorbent dosage, type and volume of eluting solvent, and time for desorption, were systematically optimized. Under the optimized conditions, the method showed good linearity (R² = 0.998–1.000) within the concentration range of 0.1–5 ng L⁻¹. The developed procedure was successfully applied to Nile River, agricultural wastewater, and groundwater samples, achieving recoveries between 87.1% and 101.2% with RSDs below 4.0%. The detection limits were 0.005–0.010 mg L⁻¹ at a signal-to-noise ratio of 3.0. Overall, the MnO₂@CGO-based µ-SPE method offers a sensitive, reliable, and straightforward approach for monitoring trace levels of organochlorine pesticides in environmental waters. Full article