High-resolution Orbitrap Mass Spectrometry Research Articles

Molecular characterization of petroleum acids from diverse geological origins via n-Butylsilane reduction

Petroleum acids are widely present in crude oil and are important indicators of generation and preservation of the crude oil. However, it is difficult to analyze these compounds using gas chromatography due to their strong polarity and low volatility. In this work, we established a method to reduce petroleum acids into corresponding hydrocarbons using n-butylsilane as the reducing agent. The reduced products of the acids from three crude oils with different geological origin were analyzed by gas chromatography-mass spectrometry and high resolution Orbitrap mass spectrometry coupled with electrospray ionization. Various hydrocarbons with specific biomarker carbon skeletons were identified in the reduced products and compared to the corresponding compounds in the saturates of the crude oils, which provides molecular clues for the understanding of the geochemical formation mechanism of petroleum acids. The results show large difference in molecular composition of petroleum acids in different crude oils. The Liaohe acids were composed of fatty acids which should be primary acids in source rock or derived from low-maturity kerogen. In contrast, the Xinjiang and Shengli acids were dominated with naphthenic acids. Xinjiang naphthenic acids showed good consistency in carbon skeleton and carbon number with the saturates. This indicates that these naphthenic acids originate from the bio-oxidation and degradation of cycloalkanes, which can also be further decarboxylated and degraded to generate cycloalkanes. Abundant 8,14-secohopanes and 25-norhopanes and corresponding acids were detected in Shengli crude oil. The compositional differences between the acids and corresponding hydrocarbons suggests that biodegradation occurs preferentially on large molecules with long side chains and has structural selectivity on the isomers. The results implies that 25-norhopanic acids seems to be the intermediates for the biodegradation of hopanes to 25-norhopanes.

The influence of storage conditions on the quality of Schisandra chinensis fruits: A integrated investigation of constituent and antioxidant activity

Schisandra chinensis is a functional fruit with tonic effect and was widely used by traditional Chinese medicine for treatment and health care. The quality of Schisandra chinensis fruit may vary by different storage condition. In this study, the influence of ambient temperature, humidity, packaging materials and period of storage on the quality of Schisandra chinensis fruits were investigated. The contents of main active components lignans and organic acids were simultaneously determined by ultra-performance liquid chromatography coupled to quadrupole electrostatic field orbitrap high resolution mass spectrometry (UPLC Orbitrap HRMS). The antioxidant activity was determined using DPPH radical scavenging capacity, ABTS+ inhibition rate and FRAP value. The correlation of multicomponent and antioxidant activity was analyzed by grey relevance analysis. Taking the changes of multicomponent and antioxidant activity as investigation index, Schisandra chinensis fruits under different storage conditions was comprehensively evaluated. Schisandrol A, malic acid, sorbic acid, schizandrin A, schizandrin B, and schisandrol B were the main effective components of antioxidant activity. Ambient temperature at 5 °C and humidity at 40 % were more suitable for Schisandra chinensis fruits and kraft paper bag was better packaging material. Do not exceed 1 year was the effective storage period. For the safety evaluation, no aflatoxin was detected within the storage period of 2 years, demonstrated the storage was satisfactory. This study provided a reference for the high-quality storage and standardized operating procedures for storage of Schisandra chinensis fruits.

Validation of the traditional antimicrobial use of the Iranian medicinal plant Thymus daenensis Celak through phytochemical characterization of its bioactive constituents

Thymus daenensis Celak (Lamiaceae family), known as denaian thyme, is an Iranian endemic plant, commonly used for its carminative, expectorant, antibacterial and antifungal properties. Previous studies report the chemical profile of the essential oil of T. daenensis aerial parts, but little is known about its non volatile constituents. Herein, phytochemical and biological investigation of the polar extract of T. daenensis aerial parts to provide further insight into traditional use of this plant has been accomplished. High-performance liquid chromatography coupled to linear ion-trap and orbitrap high-resolution mass spectrometry (LC-ESI/LTQOrbitrap/MS/MS) analysis of MeOH extract was performed to guide the isolation of specialized metabolites and successive characterization by NMR analysis. MeOH extract displayed antioxidant activity evaluated by DPPH (EC50 = 48.99 ± 1.47 μg/mL) and TEAC assay (1.37 mg/mL). Successively, the biofilm inhibitory activity of extract and isolated compounds against mature biofilms of Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Listeria monocytogenes, and Staphylococcus aureus, and their influence on the metabolism of sessile bacterial cells were evaluated. Two previously unreported thymol derivatives have been identified. The biofilm inhibitory activity of isolated compounds highlighted a promising antimicrobial action for the tested compounds. In particular, vanillic acid, (3S,5R,6R,7E,9S)-megastigm-7-ene-3,5,6,9-tetrol 3-O-β-D-glucopyranoside, thymoquinol-2-O-β-D-glucopyranoside and the never reported compound daenol resulted capable of exerting inhibitory activity vs all pathogenic strains. All compounds tested at a concentration of 10 μg/mL inhibited the metabolism of the sessile cells of E. coli at a percentage ranging between 37.7% and 77.39%, and of L.monocytogenes at a percentage ranging between 21.79% and 71.17%.

Quantitative Non-targeted Screening to Profile Micropollutants in Sewage Sludge Used for Agricultural Field Amendments.

A considerable number of micropollutants from human activities enter the wastewater network for removal. However, at the wastewater treatment plant (WWTP), some proportion of these compounds is retained in the sewage sludge (biosolids), and due to its high content of nutrients, sludge is widely applied as an agricultural fertilizer and becomes a means for the micropollutants to be introduced to the environment. Accordingly, a holistic semiquantitative nontarget screening was performed on sewage sludges from five different WWTPs using nanoflow liquid chromatography coupled to high-resolution Orbitrap mass spectrometry. Sixty-one inorganic elements were measured using inductively coupled plasma mass spectrometry. Across all sludges, the nontarget analysis workflow annotated >21,000 features with chemical structures, and after strict prioritization and filtering, 120 organic micropollutants with diverse chemical structures and applications such as pharmaceuticals, pesticides, flame retardants, and industrial and natural compounds were identified. None of the tested sludges were free from organic micropollutants. Pharmaceuticals contributed the largest share followed by pesticides and natural products. The predicted concentration of identified contaminants ranged between 0.2 and 10,881 ng/g dry matter. Through quantitative nontarget analysis, this study comprehensively demonstrated the occurrence of cocktails of micropollutants in sewage sludges.

Metabolic profiling of lumateperone in vitro and in vivo by UPLC-Q Exactive Orbitrap HRMS, and its pharmacokinetic study in rat plasma by LC-MS/MS

Lumateperone is a novel agent approved by FDA for treatment of schizophrenia in adults. To elucidate the species differences in the of biotransformation of lumateperone and its pharmacokinetic (PK) characteristics in rats, the metabolite identification of lumateperone was carried out in rat, dog and human liver microsomes, and rat plasma after oral administration using UPLC-Q Exactive Orbitrap high-resolution mass spectrometry HRMS. Furtherly, the PK characteristics of lumateperone and its N-demethylated metabolite (M3) in rat plasma were investigated using a validated LC-MS/MS method following intravenous and oral administration. Fourteen phase I metabolites were found in liver microsomes and ten of them were observed in rat plasma. N-demethylation, carbonylation, dehydrogenation, and piperazine ring cleavage were main metabolic pathway of lumateperone. No unique metabolites were formed in human liver microsomes. After rapid absorption in rats, lumateperone was quickly metabolized and eliminated with bioavailability of less than 5%. The exposure level of M3 was about 1.5-fold higher than that of lumateperone in rat plasma. Lumatperone underwent extensive metabolism and was absorbed rapidly in rats. Metabolite M3 had equivalent or slightly higher exposure levels than lumateperone. This study provides essential PK information to facilitate further pharmacodynamic researches of lumateperone.

Trace analysis of 20 antihistamines in milk by ultrahigh performance liquid chromatography coupled with high field quadrupole orbitrap high resolution mass spectrometry followed dispersive micro solid phase extraction

Ultrahigh-performance liquid chromatography coupled with high-field quadrupole Orbitrap high resolution mass spectrometry was used for the separation and determination of 20 antihistamines, and a dispersive micro solid-phase extraction procedure using high-performance absorbing material was developed as a sample preparation strategy for extracting 20 antihistamines from milk. Instrument conditions and key parameters influencing extraction efficiency were investigated to obtain an optimized method. The limit of detection for 20 antihistamines in milk using this method is 0.05 µg/L to 1.0 µg/L. Recoveries are between 80.7 % and 108.3 %, and the relative standard deviation is less than 15 %. It is suitable for confirmatory monitoring and quantitative analysis of 20 antihistamines in milk. The results show that antihistamines in milk may be noteworthy issues for human health and environmental pollution.

High resolution mass spectrometry targeted analysis and suspect screening of pesticide residues in fruit samples and assessment of dietary exposure

Fruits consistently hold a prominent position in healthy dietary habits. Pesticides are used to manage plant diseases, achieve sustainable production, and maintain high food standards. This study utilized a comprehensive analytical technique that involved both targeted analysis and suspect screening. Analysis was conducted using Ultra-high-performance liquid chromatography coupled with hybrid Linear Trap Quadrupole (LTQ)/Orbitrap High Resolution Mass Spectrometry (HRMS) to examine pesticide levels in fruits. The matrices chosen comprised fruit commodities that are commonly consumed in Greece, including table grapes, apples, pears, citrus fruits, and strawberries. The QuEChERS approach was effectively validated for 30 specific pesticides. According to the method acceptance criteria established by SANTE, the QuEChERS method have shown exceptional efficiency in extracting the chosen pesticides, with recovery rates ranging from 70% to 120% in three concentration levels (10, 50, 100 μg kg−1). It also exhibited outstanding linearity, with an R2 more than 0.99. The method exhibited exceptional precision, with relative standard deviations (RSDs) below 20%. Additionally, the combined measurement uncertainty (MU%) was found to be acceptable, remaining below 50%The quantification limits were below 10 μg kg−1 for the majority of the analytes, satisfying the Maximum Residue Levels (MRLs) established by the European Commission. Following targeted analysis, a dietary risk assessment was performed, revealing that both acute and chronic hazard quotients (aHQ and cHQ), along with chronic hazard index (cHI) were below 1, which indicated that the studied commodities are safe for human consumption. In addition, a suspect screening workflow was developed based on an in-house database comprising 355 pesticides commonly applied to the relevant commodities and related transformation products (TPs). Overall, through suspect screening, twenty-two additional pesticides and TPs not included in the target list were identified. Hence, this approach is anticipated to function as proactive alert system guaranteeing the long-term viability of agricultural production.

Untargeted foodomics for authenticating the organic farming of water spinach (Ipomoea aquatica)

This study aimed to conduct a comprehensive analysis of the primary and secondary metabolites of water spinach (Ipomoea aquatica) using hydrophilic interaction liquid chromatography coupled with Orbitrap high-resolution mass spectrometry (HILIC-Orbitrap-HRMS). Certified samples from two cultivars, Green stem water spinach (G) and White stem water spinach (W) cultivated using organic and conventional farming methods, were collected from the Hong Kong market. Multivariate analysis was used to differentiate water spinach of different cultivars and farming methods. We identified 12 metabolites to distinguish between G and W, 26 metabolites to identify G from organic farming and 8 metabolites to identify W from organic farming. Then, two metabolites, isorhamnetin and jasmonic acid, have been proposed to serve as biomarkers for organic farming (in both G and W). Our foodomics findings provide useful tools for improving the crop performance of water spinach under abiotic/biotic stressesand authentication of organic produce.

Untargeted Metabolomics Based on Ultra-High-Performance Liquid Chromatography Coupled with Quadrupole Orbitrap High-Resolution Mass Spectrometry for Differential Metabolite Analysis of Pinelliae Rhizoma and Its Adulterants.

The present study investigates the chemical composition variances among Pinelliae Rhizoma, a widely used Chinese herbal medicine, and its common adulterants including Typhonium flagelliforme, Arisaema erubescens, and Pinellia pedatisecta. Utilizing the non-targeted metabolomics technique of employing UHPLC-Q-Orbitrap HRMS, this research aims to comprehensively delineate the metabolic profiles of Pinelliae Rhizoma and its adulterants. Multivariate statistical methods including PCA and OPLS-DA are employed for the identification of differential metabolites. Volcano plot analysis is utilized to discern upregulated and downregulated compounds. KEGG pathway analysis is conducted to elucidate the differences in metabolic pathways associated with these compounds, and significant pathway enrichment analysis is performed. A total of 769 compounds are identified through metabolomics analysis, with alkaloids being predominant, followed by lipids and lipid molecules. Significant differential metabolites were screened out based on VIP > 1 and p-value < 0.05 criteria, followed by KEGG enrichment analysis of these differential metabolites. Differential metabolites between Pinelliae Rhizoma and Typhonium flagelliforme, as well as between Pinelliae Rhizoma and Pinellia pedatisecta, are significantly enriched in the biosynthesis of amino acids and protein digestion and absorption pathways. Differential metabolites between Pinelliae Rhizoma and Arisaema erubescens are mainly enriched in tyrosine metabolism and phenylalanine metabolism pathways. These findings aim to provide valuable data support and theoretical references for further research on the pharmacological substances, resource development and utilization, and quality control of Pinelliae Rhizoma.

To Investigate the Mechanism of Qinpi Tongfeng Formula in Treating Acute Gouty Arthritis by UHPLC-Q-Orbitrap-MS, Network Pharmacology and Experimental Validation.

Acute gouty arthritis (AGA) is characterized by the accumulation of monosodium urate crystals within the joints, leading to inflammation and severe pain. Western medicine treatments have limitations in addressing this condition. Previous studies have shown the efficacy of Qinpi Tongfeng formula (QPTFF) in treating AGA, but further investigation is needed to understand its mechanism of action. We used ultra-high-performance liquid chromatography tandem Q-Exactive Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap-MS) to identify compounds in QPTFF. Target proteins regulated by these compounds were obtained from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, Chemistry Database, and Swiss Target Prediction Database. AGA-related targets were searched and screened from various databases, including Genecards, PharmGKB, Drugbank, etc. Intersection targets of QPTFF and AGA were analyzed for protein-protein interaction networks, GO function enrichment, and KEGG pathway enrichment. We then verified QPTFF's mechanism of action using an AGA rat model, assessing pathological changes via H&E staining and target expression via ELISA, RT-qPCR, and Western blot. UHPLC-Q-Orbitrap-MS identified 207 compounds in QPTFF, with 55 selected through network pharmacology. Of 589 compound-regulated targets and 1204 AGA-related targets, 183 potential targets were implicated in QPTFF's treatment of AGA. Main target proteins included IL-1β, NFKBIA, IL-6, TNF, CXCL8, and MMP9, with the IL-17 signaling pathway primarily regulated by QPTFF. Experimental results showed that medium and high doses of QPTFF significantly reduced serum inflammatory factors and MMP-9 expression, and inhibited IL-17A, IL-6, IKK-β, and NF-κB p65 mRNA and protein expression in AGA rats compared to the model group. Key targets of QPTFF include IL-1β, NFKBIA, IL-6, TNF-α, CXCL8, and MMP9. QPTFF effectively alleviates joint inflammation in AGA rats, with high doses demonstrating no liver or kidney toxicity. Its anti-inflammatory mechanism in treating AGA involves the IL-17A/NF-κB p65 signaling pathway.

Advances in Oxygen Isotope Analysis of Phosphate by Electrospray Orbitrap Mass Spectrometry for Studying the Microbial Metabolism of Microorganisms.

Understanding the impact of human activities on the metabolic state of soil and aquatic environments is of paramount importance to implement measures for maintaining ecosystem services. Variations of natural abundance 18O/16O ratios in phosphate have been proposed as proxies for the holistic assessment of metabolic activity given the crucial importance of phosphoryl transfer reactions in fundamental biological processes. However, instrumental and procedural limitations inherent to oxygen isotope analysis in phosphate and organophosphorus compounds have so far limited the stable isotope-based evaluation of metabolic processes. Here, we discuss how recent developments in Orbitrap high resolution mass spectrometry enable measurements of 18O/16O ratios in phosphate and outline the critical mass spectrometry parameters for accurate and precise analysis. Subsequently, we evaluate the types of 18O kinetic isotope effects of phosphoryl transfer reactions and illustrate how novel analytical approaches will give rise to an improved understanding of 18O/16O ratio variations from biochemical processes affecting the microbial phosphorus metabolism.

Comprehensive characterization of the compositional differences in essential oils prepared from Artemisiae argyi during different picking seasons using gas chromatography Orbitrap high-resolution mass spectrometry

BackgroundArtemisia argyi Lévl. et Vant, commonly utilized in traditional medicine, food, and therapeutic practices such as moxibustion and fumigation, yields an essential oil with significant value. Understanding the chemical composition of Artemisia argyi essential oil (AAEO) is crucial for optimizing its production and application. PurposeThis study aims to provide a detailed characterization of the chemical constituents of AAEO, thereby enhancing our understanding of its potential uses and therapeutic efficacy. MethodsThe study employed gas chromatography Orbitrap high-resolution mass spectrometry (GC-Orbitrap-HRMS) for the analytical characterization of AAEO. The AAEO samples were diluted with n-hexane and subjected to direct analysis. To enhance the accuracy and reliability of compound identification, retention indices were used for correction alongside the mass spectrometry data. This study also included a comparative analysis of AAEO from eight different batches, harvested from the same location but at distinct times, to evaluate the consistency and variability in their chemical profiles. ResultsA total of 126 compounds were putatively identified in AAEO, with the primary constituents being alkenes (43.729%), alcohols (29.102%), ketones (12.257%), and ethers (9.297%). Comparative analysis of the eight AAEO batches revealed general consistency in major components, with variations in relative concentrations and minor constituents. These variations were linked to differing impacts on tumor cell viability, suggesting batch-specific therapeutic potentials. ConclusionThe investigation successfully delineated the complex chemical landscape of AAEO, revealing both the consistency and variability across different batches. These findings underline the importance of chemical characterization in understanding and harnessing the therapeutic potential of traditional medicinal substances like AAEO.

Handling of problematic ion chromatograms with the Automated Target Screening (ATS) workflow for unsupervised analysis of high-resolution mass spectrometry data

Liquid chromatography (LC) or gas chromatography (GC) coupled to high-resolution mass spectrometry (HRMS) is a versatile analytical method for the analysis of thousands of chemical pollutants that can be found in environmental and biological samples. While the tools for handling such complex datasets have improved, there are still no fully automated workflows for targeted screening analysis. Here we present an R-based workflow that is able to cope with challenging data like noisy ion chromatograms, retention time shifts, and multiple peak patterns. The workflow can be applied to batches of HRMS data recorded after GC with electron ionization (GC-EI) and LC coupled to electrospray ionization in both negative and positive mode (LC-ESIneg/LC-ESIpos) to perform peak annotation and quantitation fully unsupervised. We used Orbitrap HRMS data of surface water extracts to compare the Automated Target Screening (ATS) workflow with data evaluations performed with the vendor software TraceFinder and the established semi-automated analysis workflow in the MZmine software. The ATS approach increased the overall evaluation performance of the peak annotation compared to the established MZmine module without the need for any post-hoc corrections. The overall accuracy increased from 0.80 to 0.86 (LC-ESIpos), from 0.77 to 0.83 (LC-ESIneg), and from 0.67 to 0.76 (GC-EI). The mean average percentage errors for quantification of ATS were around 30% compared to the manual quantification with TraceFinder. The ATS workflow enables time-efficient analysis of GC- and LC-HRMS data and accelerates and improves the applicability of target screening in studies with a large number of analytes and sample sizes without the need for manual intervention.Graphical

UPLC-QE-Orbitrap-MS combined with network pharmacology to explore differential components and mechanisms of raw and scorched rhubarb for treatment of ulcerative colitis

This study compared the therapeutic difference effects of the raw and scorched rhubarb for the treatment of ulcerative colitis(UC) and explored their difference in chemical components and mechanisms by using ultra-high performance liquid chromatography-quadrupole-electrostatic field orbitrap high-resolution mass spectrometry(UPLC-QE-Orbitrap-MS) and network pharmacology. The UC therapeutic effects of Shaoyao Decoction with the raw rhubarb or the scorched rhubarb were evaluated by dextran sulfate sodium(DSS)-induced mouse model. The results showed that Shaoyao Decoction with either the raw rhubarb or the scorched rhubarb could relieve the UC symptoms of mice to different extents, while the scorched rhubarb-based formula showed advantages in reducing hemorrhagic diarrhea and inflammation levels. UPLC-QE-Orbitrap-MS was used to identify a total of 78 small molecules in the water decoction of the raw and scorched rhubarb. Multivariate statistical methods were used to screen components increasing significantly after the scorching process. The seven compounds included five free anthraquinones, gallic acid, and 5-hydroxymethylfurfural(HMF). Meanwhile, the nine compounds decreasing scorching were mainly combined anthraquinones and catechins-related compounds. Network pharmacology and molecular docking suggested that free anthraquinones, gallic acid, and 5-HMF may act on core targets such as B-cell lymphoma-2(BCL2), epidermal growth factor receptor(EGFR), tumor necrosis factor(TNF), and caspase-3(CASP3) and influence the signaling pathways such as phosphoinositide-3-kinase/protein kinase B(PI3K/Akt), hypoxia inducible factor-1(HIF-1), TNF, and mitogen-activated protein kinase(MAPK), so as to regulate the inflammation response, oxidative stress, and cell apoptosis to relieve UC symptoms. This study compared the therapeutic effects and chemical components of the raw and scorched rhubarb, providing the clinical reference for using rhubarb to treat UC.

Mass Spectrometry-Based Method to Measure Aflatoxin B1 DNA Adducts in Formalin-Fixed Paraffin-Embedded Tissues.

Aflatoxin B1 (AFB1) is a potent human liver carcinogen produced by certain molds, particularly Aspergillus flavus and Aspergillus parasiticus, which contaminate peanuts, corn, rice, cottonseed, and ground and tree nuts, principally in warm and humid climates. AFB1 undergoes bioactivation in the liver to produce AFB1-exo-8,9-epoxide, which forms the covalently bound cationic AFB1-N7-guanine (AFB1-N7-Gua) DNA adduct. This adduct is unstable and undergoes base-catalyzed opening of the guanine imidazolium ring to form two ring-opened diastereomeric 8,9-dihydro-8-(2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl-formamido)-9-hydroxy-aflatoxin B1 (AFB1-FapyGua) adducts. The AFB1 formamidopyrimidine (Fapy) adducts induce G → T transversion mutations and are likely responsible for the carcinogenic effects of AFB1. Quantitative liquid chromatography-mass spectrometry (LC-MS) methods have shown that AFB1-N7-Gua is eliminated in rodent and human urine, whereas ring-opened AFB1-FapyGua adducts persist in rodent liver. However, fresh frozen biopsy tissues are seldom available for biomonitoring AFB1 DNA adducts in humans, impeding research advances in this potent liver carcinogen. In contrast, formalin-fixed paraffin-embedded (FFPE) specimens used for histopathological analysis are often accessible for molecular studies. However, ensuring nucleic acid quality presents a challenge due to incomplete reversal of formalin-mediated DNA cross-links, which can preclude accurate quantitative measurements of DNA adducts. In this study, employing ion trap or high-resolution accurate Orbitrap mass spectrometry, we demonstrate that ring-opened AFB1-FapyGua adducts formed in AFB1-exposed newborn mice are stable to the formalin fixation and DNA de-cross-linking retrieval processes. The AFB1-FapyGua adducts can be detected at levels comparable to those in a match of fresh frozen liver. Orbitrap MS2 measurements can detect AFB1-FapyGua at a quantification limit of 4.0 adducts per 108 bases when only 0.8 μg of DNA is assayed on the column. Thus, our breakthrough DNA retrieval technology can be adapted to screen for AFB1 DNA adducts in FFPE human liver specimens from cohorts at risk of this potent liver carcinogen.

Alkali hydrolysis of wool fibres using microwave irradiation as a recycling approach for handling wool-waste

The aim of the present work is to investigate the influence of microwave irradiation on alkali hydrolysis, under various thermochemical conditions, of wool fibres. This perspective seems to be a promising alternative for the valorization of wool waste. The reaction yield is calculated in every case in order to determine the optimum hydrolysis conditions. The solid residue, as well as the filtrate, are subjected to instrumental chemical analysis in order to identify and isolate useful products. The optimal conditions for the hydrolysis of wool resulted to be the use of 5% w/v NaOH, microwave treatment for 10 min in absence of phase-transfer catalyst. In addition, the analysis in the Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS) allowed the identification of certain small molecules like N2, H2S, NH3, C6H5OH, C4H9NO and larger ones like amino acids, such as alanine, cystine, proline, valine and leucine. Additionally, the content of wool hydrolysate was specified upon identifying several substituted products of tyrosine, proline and alanine amino acids. Liquid Chromatography–Orbitrap High-Resolution Mass Spectrometry (LC–Orbitrap HRMS) was also employed to identify the components present in the wool hydrolysate, detecting mainly various dipeptides as well as leucylproline and cysteic acid. In this light, the amino acids produced by wool alkali hydrolysis degradation could valorise the wool waste once inserted in industrial chemistry, as a prominent alternative for “greener” adhesives of two components, outlining by these means the feasibility of a practically sustainable circular economy.

Systematic qualitative analysis of terpenes in mastic (Pistacia lentiscus L.) extract and their fragmentations by UHPLC-Q-Orbitrap-HRMS.

Mastic is a natural resin produced by Pistacia lentiscus L. (Anacardiaceae). The beneficial properties of this resin are attributed to its triterpenes and volatile compounds. This study was conducted to screen and characterize the terpenes in mastic ethyl acetate extract (M-Ex). An ultrahigh-performance liquid chromatography coupled to quadrupole Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap-HRMS) method was developed for the qualitative analysis of terpenes in M-Ex. We utilized in-house-isolated compounds as reference substance (Rs), including monoterpenes (A) with α-pinane structures, tetracyclic triterpene (B) containing tirucallane skeletons, and pentacyclic triterpene (C) belonging to olean, moronic, amyrone, and lupane types. Based on the mass spectrometric characteristics of the above compounds, and the difference in characteristic diagnostic fragment ions (DFIs) in isomeric compounds, the terpene compounds were further identified in M-Ex. Out of a total of 70 compounds, including monoterpenes and tetra-, and pentacyclic triterpenes, 20 were accurately determined by Rs, retention time (RT), and DFIs. Based on the cleavage patterns summarized from the above 20 compounds and with reference to the reported literature, another 50 compounds were putatively identified. Based on our discovery, six terpenic acids with A-seco-tirucallane types and one monoterpene dimer were identified for the first time in mastic. Our research serves not only as a foundation for the rapid identification and screening of terpene compounds in mastic but also as a supplementary basis for the identification of such compounds in other types of resins.

Short- and medium-chain chlorinated paraffins in breast milk in Shanghai, China: Occurrence, characteristics, and risk assessment

As novel contaminants, short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) have been of great concern in the past several years. Shanghai was one of the provinces with the largest chlorinated paraffins (CPs) emission in China; nevertheless, there is currently little information on the human exposure to SCCPs and MCCPs, particularly MCCPs. In this study, 25 breast milk samples were collected in Shanghai from 2016 to 2017. The concentrations of SCCPs and MCCPs were determined using two-dimensional gas chromatography coupled with orbitrap high-resolution mass spectrometry (GC × GC-orbitrap-HRMS) to investigate their characteristics and assess the associated health risks for breast-fed infants. Compared with the previous studies in other areas, the current study presented the higher CPs concentrations, with median concentrations of SCCPs and MCCPs up to 771 and 125 ng/g lipid weight (lw), respectively. The exposure profiles of the CPs were characterized by C10 and Cl6-7 as the predominant congeners of SCCPs, while C14 and Cl7–9 were identified as the dominant groups of MCCPs. CP-42 and CP-52 were identified as potential sources of CPs found in breast milk samples collected in Shanghai. The concentrations of MCCPs exhibited a positive correlation (p value < 0.05) with the dietary consumption of meat and poultry. No significant positive correlations were observed for SCCPs and MCCPs with polychlorinated dibenzodioxins/furans (PCDD/Fs) congeners. A preliminary exposure assessment showed that SCCPs in breast milk potentially posed high risks to the breast-fed infants in Shanghai.

Lipidomics Analysis of Different Marine Fish Oils Using Untargeted Liquid Chromatography–Orbitrap High-Resolution Mass Spectrometry and Chemometrics

Lipidomics Analysis of Different Marine Fish Oils Using Untargeted Liquid Chromatography–Orbitrap High-Resolution Mass Spectrometry and Chemometrics

Comprehensive workflow encompassing discovery, verification, and quantification of indicator peptide in snail mucin using LC-quadrupole Orbitrap high-resolution tandem mass spectrometry

Peptidomics analysis was conducted using high-resolution tandem mass spectrometry (MS2) to determine the peptide profile of snail-derived mucin extract (SM). The study was also aimed to identify an indicator peptide and validate a quantification method for this peptide. The peptide profiling and identification were conducted using discovery-based peptidomics analysis employing data-dependent acquisition, whereas the selected peptides were verified and quantified using parallel reaction monitoring acquisition. Among the 16 identified peptides, the selected octapeptide (TEAPLNPK) was quantified via precursor ion ionization (m/z 435.2400), followed by quantification of the corresponding quantifier ion fragment (m/z 639.3824) using MS2. The quantification method was optimized and validated in terms of specificity, linearity, accuracy, precision, and limit of detection/quantification. The validated method accurately quantified the TEAPLNPK content in the SM as 7.5 ± 0.2 μg/g. Our study not only identifies an indicator peptide from SM but also introduces a novel validation method, involving precursor ion ionization and quantification of specific fragments. Our findings may serve as a comprehensive workflow for the monitoring, selection, and quantification of indicator peptides from diverse food resources.