A method for determining volatile organic compounds (VOCs) emitted from medical molecular sieve oxygen concentrators was developed using thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS). The oxygen concentrator gas was sampled at a flow rate of 0.5 L/min through a branched sampling system onto Tenax GR/carbopack B adsorption tubes. The adsorbed compounds were desorbed and introduced using a programmed temperature vaporization inlet system, followed by chromatographic separation on an SH-I-624Sil MS column. Four VOCs (BHT-Q, PTBP, BHT-quinol, and EHB) were detected in the medical oxygen concentrator using this method. Calibration curves for these compounds exhibited excellent linearity ( R ²>0.99) within the range of 3~100 ng. With a sampling volume of 20 L, the detection limit of the four VOCs ranged from 0.003 9 to 0.022 2 μg/m ³. Spike recovery rates for the four VOCs were between 95% and 115%, with relative standard deviations (RSDs) below 5% ( n=6). The method is simple, rapid, highly sensitive, and accurate, making it suitable for VOCs detection in medical molecular sieve oxygen concentrators.
Volatile Organic Compounds/analysis* ; Gas Chromatography-Mass Spectrometry/methods* ; Oxygen

OBJECTIVES: Tiletamine, a veterinary anesthetic, has emerged as a novel psychoactive substance and has been abused in many parts of the world, causing great harm to public health. However, the sensitivity of existing detection methods cannot meet the needs of forensic practice. This study aims to establish an ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of tiletamine and its metabolite desethyltiletamine in human biological samples, and to verify its applicability in forensic practice. METHODS: SKF_525A was used as the internal standard. Biological samples were extracted with acetonitrile containing 1 ng/mL SKF_525A, vortexed for 10 min, ultrasonicated for 20 min, centrifuged at 10 000 r/min for 10 min, and 500 μL of the supernatant was filtered through a 0.22 μm membrane. Analyses were performed using an ACQUITY UPLC H-Class PLUS system and an XEVO TQ-S Micro triple quadrupole mass spectrometer. An ACQUITY UPLC^® BEH C18 (1.7 µm, 2.1 mm×100 mm) column at a flow rate of 0.3 mL/min was used, and four mobile phase systems were tested to optimize separation. Detection used positive electrospray ionization (ESI+) in multiple reaction monitoring (MRM) mode, with quantifier ion transitions of mass to charge 224.043→179.016 for tiletamine and mass to charge 196.08→151.06 for desethyltiletamine. Calibration curves were established over 0.1-200 ng/mL in spiked blood samples. The linear range, limit of detection (LOD), and limit of quantification (LOQ) were determined. Low (5 ng/mL), medium (20 ng/mL), and high (100 ng/mL) concentrations of tiletamine were spiked into blood, liver, and kidney to evaluate precision, accuracy, matrix effect, recovery, and stability. Finally, actual forensic case samples were tested to validate applicability. RESULTS: The established UPLC-MS/MS method achieved simultaneous detection of tiletamine and desethyltiletamine in human biological samples, with retention times of 3.42 min and 2.82 min, respectively. Using mobile phase A (20 mmol/L ammonium acetate and 0.1% formic acid in water) and mobile phase B (acetonitrile) produced the best separation. In blood, tiletamine showed good linearity from 0.1-200 ng/mL (r=0.992, R²=0.983), LOD 0.03 ng/mL, LOQ 0.1 ng/mL, recovery 92%-107%, and matrix effect 71%-99%. In liver and kidney, recoveries were 91%-98% and 93%-104%, and matrix effects were 69%-96% and 72%-100%, respectively. Intra- and inter-day precision [expressed as relative standard deviation (RSD)] and accuracy [expressed as relative error (RE)] were within 15%, and samples were stable at -20 ℃. Tiletamine was detected in actual case samples at 0.37 μg/mL (blood), 0.15 μg/g (liver), 0.11 μg/g (kidney) in case 1, and 8.75 ng/mL (blood) in case 2; desethyltiletamine was also detected in blood. CONCLUSIONS The UPLC-MS/MS method is efficient, accurate, and sensitive, and is suitable for detecting tiletamine and desethyltiletamine in human biological samples.
Tandem Mass Spectrometry/methods* ; Humans ; Chromatography, High Pressure Liquid/methods* ; Substance Abuse Detection/methods* ; Liquid Chromatography-Mass Spectrometry

Dynamic changes in the physiochemical, structural, and flavor characteristics of ginger-juice milk curd were explored by texture analysis, scanning electron microscopy, rheometry, electronic tongue, and gas chromatography-mass spectrometry (GC-MS). Protein electrophoresis showed that ginger juice could hydrolyze α_s-, β-, and κ-casein. Curd formation was initiated at 90 s, marked by significant changes in intensity detected via intrinsic fluorescence. The contents of soluble protein and calcium decreased rapidly during coagulation, while the caseinolytic activity, storage moduli, loss moduli, hardness, adhesiveness, and water-holding capacity increased, resulting in a denser gel structure with smaller pores and fewer cavitations as observed by scanning electron microscopy. Electronic tongue analysis indicated that milk could neutralize the astringency and saltiness of ginger juice, rendering the taste of ginger-juice milk curd more akin to that of milk. Approximately 70 volatile components were detected in ginger-juice milk curd. α‍-Zingiberene, α‍-curcumene, β‍-sesquiphellandrene, and β‍-bisabolene were the predominant volatile flavor compounds, exhibiting an initial decrease in content followed by stability after 90 s. Decanoic acid, γ-elemene, and caryophyllene were identified as unique volatile compounds after mixing of milk and ginger juice. Understanding the dynamic changes in these characteristics during coagulation holds significant importance for the production of ginger-juice milk curd.
Zingiber officinale/chemistry* ; Milk/chemistry* ; Animals ; Taste ; Gas Chromatography-Mass Spectrometry ; Caseins/chemistry* ; Microscopy, Electron, Scanning ; Rheology ; Flavoring Agents

Oral squamous cell carcinoma (OSCC) is the most common manifestation of oral cancer. It has been proposed that periodontal pathogens contribute to OSCC progression, mainly by their virulence factors. However, the main periodontal pathogen and its mechanism to modulate OSCC cells remains not fully understood. In this study we investigate the main host-pathogen pathways in OSCC by computational proteomics and the mechanism behind cancer progression by the oral microbiome. The main host-pathogen pathways were analyzed in the secretome of biopsies from patients with OSCC and healthy controls by mass spectrometry. Then, functional assays were performed to evaluate the host-pathogen pathways highlighted in oral cancer. Host proteins associated with LPS response, cell migration/adhesion, and metabolism of amino acids were significantly upregulated in the human cancer proteome, whereas the complement cascade was downregulated in malignant samples. Then, the microbiome analysis revealed large number and variety of peptides from Fusobacterium nucleatum (F. nucleatum) in OSCC samples, from which several enzymes from the L-glutamate degradation pathway were found, indicating that L-glutamate from cancer cells is used as an energy source, and catabolized into butyrate by the bacteria. In fact, we observed that F. nucleatum modulates the cystine/glutamate antiporter in an OSCC cell line by increasing SLC7A11 expression, promoting L-glutamate efflux and favoring bacterial infection. Finally, our results showed that F. nucleatum and its metabolic derivates promote tumor spheroids growth, spheroids-derived cell detachment, epithelial-mesenchymal transition and Galectin-9 upregulation. Altogether, F. nucleatum promotes pro-tumoral mechanism in oral cancer.
Humans ; Fusobacterium nucleatum/metabolism* ; Mouth Neoplasms/metabolism* ; Disease Progression ; Proteomics ; Carcinoma, Squamous Cell/metabolism* ; Host-Pathogen Interactions ; Metabolic Networks and Pathways ; Case-Control Studies ; Mass Spectrometry

Chemical exposure during prenatal development has significant implications for both maternal and child health. Compared to blood, saliva is a non-invasive and less resource-intensive, alternative. Given the temporal variability of xenobiotic metabolites (XM), repeated sampling is essential. Therefore, saliva offers a valuable tool for the longitudinal assessment of prenatal exposomes. Despite its potential, no studies have explored saliva for XM measurement. This study pioneered using saliva to assess XM detectability and investigate the associations between prenatal XM and endogenous metabolomes in pregnant women. Saliva samples were analysed using mass spectrometry from 80 pregnant women at 24-34 weeks gestation. Metabolomes and exposomes were annotated using the Human Metabolome and U.S. Environmental Protection Agency databases. Metabolome-XM associations were clustered using Glay community clustering. Linear regression models, adjusted for age, estimated associations between catecholamines and XMs. XM levels were validated in a cohort of women (n = 14) with and without preeclampsia. Our study identified 582 metabolomes and 125 XM in saliva, demonstrating its potential as a matrix for exposure measurement. After false discovery rate correction, 18 109 significant metabolome-XM associations were identified. Community clustering revealed 37 connected clusters, with the largest cluster (238 nodes) enriched in tyrosine and catecholamine metabolism. Food-contact-chemicals and food-additives were significantly associated with higher catecholamine and their metabolite levels. Subgroup analyses revealed higher concentrations of these chemicals in women with preeclampsia compared to healthy controls. This study demonstrates that saliva contains valuable molecular data for measuring exposomes. Food-related chemicals were associated with higher catecholamine levels, which may be relevant to the prevalence of hypertensive crises in pregnancy.
Humans ; Female ; Pregnancy ; Saliva/metabolism* ; Pre-Eclampsia/metabolism* ; Xenobiotics/analysis* ; Adult ; Metabolome ; Maternal Health ; Mass Spectrometry

Natural products (NPs) have long held a significant position in various fields such as medicine, food, agriculture, and materials. The chemical space covered by NPs is extensive but often underexplored. Therefore, high-throughput and efficient methodologies for the annotation and discovery of NPs are desired to address the complexity and diversity of NP-based systems. Mass spectrometry (MS) has emerged as a powerful platform for the annotation and discovery of NPs. MS databases provide vital support for the structural characterization of NPs by integrating extensive mass spectral data and sample information. Additionally, the released annotation methodologies, based on a variety of informatics tools, continuously improve the ability to annotate the structure and properties of compounds. This review examines the current mainstream databases and annotation methodologies, focusing on their advantages and limitations. Prospects for future technological advancements are then discussed in terms of novel applications and research objectives. Through a systematic overview, this review aims to provide valuable insights and a reference for MS-based NPs annotation, thereby promoting the discovery of novel natural entities.
Biological Products/chemistry* ; Mass Spectrometry/methods* ; Databases, Factual ; Drug Discovery/methods* ; Humans

Aconiti Lateralis Radix Praeparata (Fuzi) represents a significant traditional Chinese medicine (TCM) that exhibits both notable pharmacological effects and toxicity. Various processing methods are implemented to reduce the toxicity of raw Fuzi by modifying its toxic and effective components, primarily diterpenoid alkaloids. To comprehensively analyze the chemical variations between different Fuzi products, ultra-high performance liquid chromatography-linear ion trap quadrupole Orbitrap mass spectrometry (UHPLC-LTQ-Orbitrap MS) was employed to systematically characterize Shengfuzi, Heishunpian and Baifupian. A total of 249 diterpenoid alkaloids present in Shengfuzi were identified, while only 111 and 61 in Heishunpian and Baifupian were detected respectively, indicating substantial differences among these products. An untargeted metabolomics approach combined with multivariate statistical analysis revealed 42 potential chemical markers. Through subsequent validation using 52 batches of commercial Heishunpian and Baifupian samples, 8 robust markers distinguishing these products were identified, including AC1-propanoic acid-3OH, HE-glucoside, HE-hydroxyvaleric acid-2OH, dihydrosphingosine, N-dodecoxycarbonylvaline and three unknown compounds. Additionally, the MS imaging (MSI) technique was utilized to visualize the spatial distribution of chemical constituents in raw Fuzi, revealing how different processing procedures affect the chemical variations between Heishunpian and Baifupian. The distribution patterns of different diterpenoid alkaloid subtypes partially explained the chemical differences among products. This research provides valuable insights into the material basis for future investigations of different Fuzi products.
Diterpenes/chemistry* ; Alkaloids/chemistry* ; Chromatography, High Pressure Liquid/methods* ; Aconitum/chemistry* ; Drugs, Chinese Herbal/chemistry* ; Metabolomics ; Mass Spectrometry/methods* ; Plant Roots/chemistry* ; Molecular Structure

(±)-Penicithrones A-D (1a/1b-4a/4b), four novel pairs of anthrone-cyclopentenone heterodimers characterized by a distinctive bridged 6/6/6-5 tetracyclic core skeleton, together with three previously identified compounds (5-7), were isolated from the crude extract of the mangrove-derived fungus Penicillium sp., guided by heteronuclear single quantum correlation (HSQC)-based small molecule accurate recognition technology (SMART 2.0) and liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based molecular networking. The structural elucidation of new compounds was accomplished through comprehensive spectroscopic analysis, and their absolute configurations were determined using DP4+ ¹³C nuclear magnetic resonance (NMR) calculations and electronic circular dichroism (ECD) calculations. Compounds 1a/1b-4a/4b demonstrated moderate cytotoxicity against three human cancer cell lines HeLa, HCT116 and MCF-7 with half maximal inhibitory concentration (IC₅₀) values ranging from 15.95 ± 1.64 to 28.56 ± 2.59 μmol·L^-1.
Humans ; Penicillium/chemistry* ; Molecular Structure ; Cyclopentanes/isolation & purification* ; Cell Line, Tumor ; Antineoplastic Agents/pharmacology* ; Tandem Mass Spectrometry ; Dimerization ; HeLa Cells ; Magnetic Resonance Spectroscopy

OBJECTIVE: To compare the lipid metabolites in the seminal plasma of normal fertile men from those of the patients with oligoasthenoteratozoospermia (OAT), and perform a pathway enrichment analysis on the differentially expressed lipids. METHODS: According to strict inclusion and exclusion criteria, we recruited 30 males seeking medical attention in our Center of Reproductive Medicine and equally divided them into an OAT and a normal fertile control group. Employing the untargeted metabolomics approach, we screened the differential lipids in the seminal plasma of the OAT patients and subjected them to pathway enrichment analysis using the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database. RESULTS: In the OAT patients, the expressions of 22 lipids were significantly upregulated and those of 32 downregulated in the positive ion mode, and the expressions of 2 lipids upregulated and those of 12 downregulated in the negative ion mode. And 5 of the significantly downregulated lipids, namely anandamide(20:4,n-6), adrenic acid, cis-gondoic acid, (3'-sulfo)galbeta-cer(d18:1/24:1(15Z)) and palmitoylcarnitine, were associated with 4 branches and 8 sub-branches of the KEGG metabolic pathways, among which the differential lipid anandamide (20:4,n-6) was involved in the regeneration of the biological system in the KEGG sub-pathway and considered to be a significantly differentially enriched pathway. CONCLUSION Lipid metabolites in the seminal plasma of OAT patients are significantly different from those in normal fertile males, and the differential lipid anandamide (20:4,n-6) may be involved in the regulation of sperm function and play an important role in male fertility.
Humans ; Male ; Semen/metabolism* ; Adult ; Lipids/analysis* ; Case-Control Studies ; Asthenozoospermia/metabolism* ; Oligospermia/metabolism* ; Lipid Metabolism ; Mass Spectrometry

BACKGROUND: Icaridin and DEET are common insect repellents widely used on human skin and clothing (skin-insect repellents [skin-IR]) to repel common pests, such as mosquitoes and biting flies. Novel analytical methods for urinary skin-IR exposure biomarkers that can be effectively applied in epidemiological studies and provide strong evidence related to risk assessment associated with daily exposure are required. In this study, we aimed to develop a method for analyzing the concentrations of icaridin, DEET, and two DEET metabolites N,N-diethyl-3-(hydroxymethyl) benzamide and 3-(diethylcarbamoyl) benzoic acid in human urine. METHODS: In this analysis, after formic acid-induced acidification of the urine sample, exposure biomarkers were extracted using solid-phase extraction composed of a modified polystyrenedivinylbenzene polymer for reversed phase (hydrophobic) retention. Subsequently, high-performance liquid chromatography-tandem mass spectrometry was performed within 10 min for a separation analysis. The present method was applied to five Japanese adults (aged 20-43 years) who used icaridin or DEET-containing products within a week. RESULTS: Limits of detection were 0.06-0.11 µg/L. Extraction recoveries were 74%-88%. The intraday and interday variations were 1.5-17.5 and 0.9-15.8% relative standard deviation, respectively. All exposure biomarkers were successfully detected in all five adults. Urinary concentrations of exposure biomarkers reached their maximum values within 15 h after starting to use skin-IR. CONCLUSIONS This method was successful in measuring urinary exposure biomarkers of skin-IR, including icaridin and DEET. Moreover, this study presents the first application of biomonitoring of urinary icaridin concentrations after using a commercial product.
Humans ; Solid Phase Extraction/methods* ; Tandem Mass Spectrometry/methods* ; Adult ; Insect Repellents/urine* ; DEET/urine* ; Young Adult ; Male ; Japan ; Female ; Chromatography, Liquid ; Biomarkers/urine* ; Chromatography, High Pressure Liquid ; East Asian People