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• A SPME Arrow-UPLC-Q-TOF-MS method was developed. • The 2D-Ni-MOF material is used for the coating of SPME Arrow. • The 2D-Ni-MOF showed superior extraction capacity to three veterinary drugs. • This method was applied to detect three veterinary drugs in milk and pork. This study presents a method utilizing solid-phase microextraction Arrow (SPME Arrow) combined with ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) for the selective detection of three veterinary drugs-thiabendazole, sulfamethazine, and clenbuterol-in milk and pork. Two-dimensional metal-organic framework nanosheets (2D-MOFs) were employed as coating materials for the SPME Arrow. Three types of 2D-MOFs (Ni, Mn, and Co based) were synthesized and characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and a physical adsorption analyzer. The 2D-MOF coatings were fabricated using the electrospinning technique, with polyacrylonitrile (PAN) serving as the binder. Comparative analysis of the three 2D-MOF coatings revealed that 2D-Ni-MOF was the optimal coating material for the SPME Arrow. Optimization of the coating preparation conditions and SPME procedures included determining the optimal mass ratio of 2D-Ni-MOF to PAN, electrospinning time, and extraction and desorption parameters. Equilibrium extraction was achieved within 60 min, and desorption was completed within 30 min. Subsequently, the 2D-Ni-MOF-SPME Arrow-UPLC-Q-TOF-MS method was established and validated under optimal conditions, demonstrating high precision with inter-day precision ranging from 3.8 % to 9.5 % and intra-day precision ranging from 5.1 % to 11.5 %. The reusability study indicated that the extraction performance of the new SPME Arrow remained consistent after 90 adsorption-desorption cycles. The method exhibited linearity in milk and pork over the ranges of 0.002–5 μg L–1 and 0.01–5 μg L–1, respectively. The detection limits in milk and pork were 0.001–0.004 μg L–1 and 0.003–0.007 μg L–1, respectively. This method demonstrated excellent applicability for determining residues of the three veterinary drugs in milk and pork. [ABSTRACT FROM AUTHOR]

• Toxic aristolochia plants were identified by targeted metabolomics. • Combining SPE and UHPLC-IM-Q-TOF/MS for highly sensitive detection. • Aristolochic acids and DNA adducts were identified using CCS and fragments. Aristolochic acids are one of the major compounds in aristolochia plants, which are nephrotoxic and carcinogenic. A method was established for the detection and identification of aristolochic acids and their DNA adducts in four different herbs using ultra-high performance liquid chromatography-ion mobility quadrupole time-of flight mass spectrometry. Solid phase extraction conditions were optimized to improve the sensitivity of the experiment by using 40 mg of C 18 as adsorbent and 100 μL ethanol as elution solvent. At a collision energy of 10-40 eV, these compounds and cleavage patterns were precisely identified and analyzed by secondary fragmentation and collision cross section values. The obtained mass spectrometry data were then analyzed by targeted metabolomics, including principal component analysis, partial least squares-discriminant analysis and hierarchical clustering analysis, and importing the samples in the established model, the confidence values can reach 0.61 and 0.76. All in all, this method can provide a useful tool for the detection of aristolochic acids and deoxyribonucleic acid adducts. In conclusion, this method was successfully used for the detection and identification of aristolochic acids and their DNA adducts. [ABSTRACT FROM AUTHOR]

• Umami peptides from enzymatic hydrolysate of Katsuwonus pelamis were investigated. • EAD-based micro-UPLC-QTOF-MS protocol was performed for peptides identification. • The taste property and umami-enhance effect of identified peptides were evaluated. • Taste mechanism was investigated by molecular docking and dynamics simulations. • It allowed for the comprehensive understanding of the molecular-level interactions. In this study, the enzymatic hydrolysates of skipjack tuna, Katsuwonus pelamis , were purified by ultrafiltration and further identified through micro-ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (micro-UPLC-QTOF-MS). The potential umami peptides were identified using both conventional collision-induced dissociation (CID) and novel electron-activated dissociation (EAD) fragmentation techniques. Nine novel umami peptides with iUmami-SCM > 588 were screened. Sensory evaluation and electronic tongue analysis were performed to confirm the taste characteristics of the umami peptides, indicating that these umami peptides all exhibited varying degrees of umami taste. Molecular docking and molecular dynamics simulation were utilized to investigate the interaction with T1R1/T1R3 taste receptors. The docking results revealed that Asp234, Ser23, Glu231, and Ile237 appeared most frequently in all docking sites and formed stable complexes through hydrogen bonding and electrostatic interactions. Furthermore, molecular dynamics simulation allowed for a more comprehensive analysis of their interactions within a dynamic environment, providing a deeper understanding of the umami perception mechanism involving umami peptides and receptors. [ABSTRACT FROM AUTHOR]

• PFAS emission from functional textiles in firefighter turnout gear heated to 38 °C was investigated. • TD-GC×GC-TOF MS was shown to provide a comprehensive emission profile for functional textiles. • 8 PFAS species were identified using targeted profiling. • Chemical differentiators were uncovered for both wear and layer type using non-targeted screening. Per- and polyfluoroalkyl substances (PFAS), in the polymeric form, have been used extensively in functional textiles, including firefighter's turnout gear (e.g., jackets and pants), where PFAS are applied to confer oil and water resistance. However, growing concerns over the persistence, potential toxicity, and environmental impact of PFAS have prompted a thorough assessment of potential exposure pathways. Here, we report the emission of PFAS from three firefighter turnout gear jackets at 38 °C. Volatile emissions from the three layers (outer layer, moisture barrier, and thermal liner) were collected onto sorbent tubes via dynamic headspace sampling using a micro-scale chamber device kept at 38 °C for one hour. The emission was characterized using thermal desorption (TD) coupled to two-dimensional gas chromatography - time-of-flight mass spectrometry (GC×GC–TOF MS). The enhanced separation capacity of GC×GC was essential due to the high number of compounds present in each sample, especially for the fabrics from used turnout gear jackets. Based on the filtering expressions, including two-dimensional retention time (1t r and 2t r) and PFAS diagnostic fragment ions (m/z 69, 95, and 131), fluorotelomer alcohols (FTOHs) and fluorotelomer acrylates were identified using standards and spectral matching with the NIST database. After conducting a non-targeted tile-based workflow, jackets (both used and unused) and layers were compared, resulting in the identification of the top 15 discriminating features from over 400 chromatographic peaks. Finally, preliminary FTOH emission experiments showed some usage and layers trends that are aligned with those reported using solvent extraction. Highest levels of FTOHs were found in the moisture barrier, followed by the outer layer and the thermal liner. Older jackets emitted higher levels of 8:2 FTOH and 10:2 FTOH than a newer jacket. In contrast, a newer jacket used for one year had emissions containing higher levels of 6:2 FTOH. Investigating routes of exposure and identifying new PFAS targets are critical steps in evaluating the environmental and health impacts of these persistent chemicals. [ABSTRACT FROM AUTHOR]

• A strategy was proposed to characterize wide-polarity metabolites of P. vulgaris. • Offline 2D-LC/IM-QTOF-HDMSE enabled characterization of 255 components. • CCS prediction and targeted compounds isolation improved identification accuracy. • HILIC/IM-QTOF-MSE could characterize 17 highly polar compounds. Metabolites identification is crucial to develop functional foods or perform quality control. Prunella vulgaris (Xia-Ku-Cao) is a medicinal and edible plant used as the herbal medicine or main additive in functional beverage. However, current analytical strategies can only on-line characterize tens of compounds, restricted by insufficient chromatographic resolution and low coverage of the mass spectrometric scan methods. This work was designed to characterize the wide-polarity components from the ear of P. vulgaris. The total extract was fractionated by semi-preparative high-performance liquid chromatography into the retained medium-polarity fraction and unretained polar fraction, which were further analyzed by offline two-dimensional liquid chromatography (2D-LC) and hydrophilic interaction chromatography, respectively. Data-independent high-definition MSE of the Vion™ ion mobility time-of-flight mass spectrometer was utilized enabling the high-coverage acquisition of collision-induced dissociation-MS2 data. The offline 2D-LC, configuring the XBridge Amide and HSS T3 columns, gave high orthogonality (0.81) and effective peak capacity (1555). Automatic peak annotation facilitated by the UNIFI™ bioinformatics platform and comparison with 62 reference compounds achieved the efficient and more reliable structural elucidation. We could characterize 255 compounds from P. vulgaris , with numerous phenylpropanoid phenolic acids and triterpenoid O -glycosides newly reported. Especially, collision cross section (CCS) prediction and targeted isolation of three compounds assisted in the identification of 39 groups of isomers. Additionally, 17 hydrophilic compounds, involving oligosaccharides and organic acids, were characterized from the unretained polar fraction. Conclusively, the in-depth metabolites identification of P. vulgaris was accomplished, and the results can benefit the development and better quality control of this valuable plant. [ABSTRACT FROM AUTHOR]

• Weifuchun analyzed using HPLC/UPLC-Q-TOF-MS. • Chromatography identifies and quantifies diverse compounds. • Network pharmacology predicts bioactive targets. • Integration of advanced analytical and computational methods. • Insights into multi-component, multi-targets, and multi-pathway interactions. Weifuchun, a Chinese medicinal prescription made from herbs of natural origin including Hongshen (Ginseng Radix et Rhizoma Rubra), Xiangchacai (Rabdosia Amethystoides), and Zhiqiao (Aurantii Fructus), has attracted increasing attention for clinically treating chronic atrophic gastritis, which is characterized by the chronic inflammation of the gastric mucosa leading to progressive loss of gastric glandular cells. To investigate the active ingredients and potential mechanisms of WFC, it was analyzed using a novel multi-component, multi-target, and multi-pathway prediction method. High/ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC/UPLC-Q-TOF-MS) was employed to separate and profile the chemical constituents of WFC with high precision and efficiency. Network analysis and molecular docking were used to predict bioactive compounds and their interactions with biological targets. The results highlight 42 significant compounds potentially contributing to the therapeutic effects of WFC by effecting on several key pathways, including proved PI3K/Akt, NF-κB, and JAK/STAT signaling pathways. This study showcases the efficacy of combining advanced chromatographic techniques with computational methods to elucidate the pharmacological mechanisms of complex botanical drugs. [ABSTRACT FROM AUTHOR]

• Overcoming one-shot limitation of thermal desorption via sample re-collection. • Assessing recollection accuracy and precision. • Recollection and analyzing standards and breath samples using GC×GC-TOFMS. • Compounds' properties, sample moisture, and desorption parameters affect recollection. In this study, we aimed to assess the feasibility of re-collecting breath samples using the Centri® (Markes International, Bridgend, UK) followed by two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) analysis. The work was conducted in two main phases. In the first phase, we evaluated the re-collection performance by analyzing two sets of standards, including a Grob mix primary solution and a standard mixture of 20 selected volatile compounds (VCs) covering different classes of organic species commonly found in breath samples. The intra-day and inter-day precision (reported as relative standard deviation (RSD),%) for the re-collection of the Grob mix primary solution were in the range of 1 % to14 % and 3 % to12 %, respectively. The re-collection accuracy ranged from 78 % to 97 %. The intra-day RSD for the re-collection of the standard mixture of selected VCs was within 20 % for all compounds, except for acetone and nonane. The precision was within 25 % for all compounds, except for nonane, n -hexane, 1,4-dichlorobenzene, and decane, which exhibited less than 36 % RSD. The re-collection accuracy was in the range of 67 % to 129 %. In the second phase of the study, the re-collection performance in breath analysis was evaluated via five repetitive splitting and re-collection of six breath samples obtained from healthy adults, realizing a total of 30 breath analyses. Initially, we evaluated the re-collection performance by considering all features obtained from breath analysis and then focused on the 20 VCs commonly found in breath samples. The re-collection accuracy for total breath features ranged from 86 to 103 %, and the RSDs were in the range of 1.0 % to 10.4 %. For the selected VCs, the re-collection accuracy of all compounds, except for undecane and benzene, was in the range of 71 % to 132 %. [ABSTRACT FROM AUTHOR]

• A robust platform with two-step data mining strategy. • UPLC/Q-TOF-MS/MS analysis provided comprehensive structural information for the three original components of rhubarb. • 356 compounds were effectively discovered and identified, including 150 acylglucosides, 125 anthraquinone, 65 flavanols, and 15 other compounds. In this study, the collision induced dissociation tandem mass spectrometry (CID-MS/MS) fragmentation pathway of chemical components in rhubarb was wholly explored using 34 standards by UHPLC-QTOF-MS/MS in negative ion mode. In consequently, the diagnostic product ions for speedy screening and categorization of chemical components in rhubarb were ascertained based on their MS/MS splitting decomposition patterns and intensity analysis. According to these findings, a fresh two-step data mining strategy had set up. The initial key step involves the use of characteristic product ions and neutral loss to screen for different types of substituents and basic skeletons of compounds. The subsequent key step is to screen and classify different types of compounds based on their characteristic product ions. This method can be utilized for rapid research, classification, and identification of compounds in rhubarb. A total of 356 compounds were rapidly identified or tentatively characterized in three rhubarb species extracts, including 150 acylglucoside, 125 anthraquinone, 65 flavanols and 15 other compounds. This study manifests that the analytical strategy is feasible for the analysis of complex natural products in rhubarb. [ABSTRACT FROM AUTHOR]

• Two orthogonal characteristics of moisture damaged cacao beans were simultaneously analyzed. • Molding kinetics and geographical region of origin were found to be orthogonally related. • Tile-based Fisher-ratio analysis was orthogonally applied for comprehensive hit discovery of 591 hits. • Each analyte composite chemical fingerprint (CCF) captured kinetic and region characteristics. • A null distribution approach along with PCA provided insight into the 591 analyte CCFs. Herein, two "orthogonal" characteristics of moisture damaged cacao beans (temporally dependent molding kinetics versus the time-independent geographical region of origin) are simultaneously analyzed in a comprehensive two-dimensional (2D) gas chromatography time-of-flight mass spectrometry (GC×GC-TOFMS) dataset using tile-based Fisher ratio (F-ratio) analysis. Cacao beans from six geographical regions were analyzed once a day for six days following the initiation of moisture damage to trigger the molding process. Thus, there are two "extremes" to the experimental sample class design: six time points for the molding kinetics versus the six geographical regions of origin, resulting in a 6 × 6 element signal array referred to as a composite chemical fingerprint (CCF) for each analyte. Usually, this study would involve initial generation of two separate hit lists using F-ratio analysis, one hit list from inputting the data with the six time point classes, then another hit list from inputting the dataset from the perspective of geographic region of origin. However, analysis of two separate hit lists with the intent to distill them down to one hit list is extremely time-consuming and fraught with shortcomings due to the challenges associated with attempting to match analytes across two hit lists. To address this challenge, tile-based F-ratio analysis is "orthogonally applied" to each analyte CCF to simultaneously determine two F-ratios at the chromatographic 2D location (F-ratio kinetic and F-ratio region) for each hit, by ranking a single hit list using the higher of the two F-ratios resulting in the discovery of 591 analytes. Further, using a pseudo-null distribution approach, at the 99.9% threshold over 400 analytes were deemed suitable for PCA classification. Using a more stringent 99.999% threshold, over 100 analytes were explored more deeply using PARAFAC to provide a purified mass spectrum. [ABSTRACT FROM AUTHOR]

• A feasible multistage intelligent data annotation strategy (MIDA) was proposed. • The MIDA provided an accurate and efficient visually annotation of complex sample. • Molecular network improved the cluster advantage of diagnostic ions. • Totally 279 components were identified from Fufang Yinhua Jiedu granules (FYJG). • Novel structures of 12 indole alkaloids and 4 organic acids were speculated. Fufang Yinhua Jiedu granules (FYJG) is a Traditional Chinese Medicine (TCM) compound formulae preparation comprising ten herbal drugs, which has been widely used for the treatment of influenza with wind-heat type and upper respiratory tract infections. However, the phytochemical constituents of FYJG have rarely been reported, and its constituent composition still needs to be elucidated. The complexity of the natural ingredients of TCMs and the diversity of preparations are the major obstacles to fully characterizing their constituents. In this study, an innovative and intelligent analysis strategy was built to comprehensively characterize the constituents of FYJG and assign source attribution to all components. Firstly, a simple and highly efficient ultra-high-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MSE) method was established to analyze the FYJG and ten single herbs. High-accuracy MS/MS data were acquired under two collision energies using high-definition MSE in the negative and positive modes. Secondly, a multistage intelligent data annotation strategy was developed and used to rapidly screen out and identify the compounds of FYJG, which was integrated with various online software and data processing platforms. The in-house chemical library of 2949 compounds was created and operated in the UNIFI software to enable automatic peak annotation of the MSE data. Then, the acquired MS data were processed by MS-DIAL, and a feature-based molecular networking (FBMN) was constructed on the Global Natural Product Social Molecular Networking (GNPS) to infer potential compositions of FYJG by rapidly classifying and visualizing. It was simultaneously using the MZmine software to recognize the source attribution of ingredients. On this basis, the unique chemical categories and characteristics of herbaceous plant species are utilized further to verify the accuracy of the source attribution of multi-components. This comprehensive analysis successfully identified or tentatively characterized 279 compounds in FYJG, including flavonoids, phenolic acids, coumarins, saponins, alkaloids, lignans, and phenylethanoids. Notably, twelve indole alkaloids and four organic acids from Isatidis Folium were characterized in this formula for the first time. This study demonstrates a potential superiority to identify compounds in complex TCM formulas using high-definition MSE and computer software-assisted structural analysis tools, which can obtain high-quality MS/MS spectra, effectively distinguish isomers, and improve the coverage of trace components. This study elucidates the various components and sources of FYJG and provides a theoretical basis for its further clinical development and application. [ABSTRACT FROM AUTHOR]

• A novel dual-channel GC × GC–TOFMS instrument equipped with an online water sample pretreatment platform for online monitoring of both VOCs and SVOCs in water was fabricated for the first time. • The pretreatment methods of headspace and liquid–liquid extraction, for VOCs and SVOCs, respectively, were integrated into a single pretreatment platform and conducted automatically and online. • 159 types of target VOCs and SVOCs were quantitatively analyzed, with a satisfying result. Screening of nontarget pollutants is conducted simultaneously. The monitoring of organic compounds in aquatic matrices poses challenges due to its complexity and time-intensive nature. To address these challenges, we introduce a novel approach utilizing a dual-channel mono (1D) and comprehensive two-dimensional (2D) gas chromatography coupled with time-of-flight mass spectrometry (GC × GC–TOFMS) system, integrated with a robotic pretreatment platform, for online monitoring of both volatile organic compounds (VOCs) and semivolatile organic compounds (SVOCs) in water matrices. Employing the robotic platform, we establish a suite of online liquid–liquid extraction (LLE) pretreatment processes for water samples, marking the first instance of such procedures. Leveraging the automatic headspace (HS) module, dual robotic preparations of HS and LLE are sequentially executed to extract VOCs and SVOCs from water matrices. The GC × GC–TOFMS system is distinguished by its dual-channel analytical column configuration, facilitating sequential analysis of VOCs in GC–TOFMS mode and SVOCs in GC × GC–TOFMS mode. Quantitative detection of 55 target VOCs and 104 SVOCs is achieved in a water sample using the instrument system. Our method demonstrates excellent correlation coefficients ranging from 0.990 to 1.000, method detection limits ranging from 0.08 to 4.78 μg L–1, relative standard deviations below 19.3 %, and recovery rates ranging from 50.0 % to 124.0 %. To validate the online monitoring capabilities of our system, we assess target SVOCs at three different concentration levels over a 3-day period. Most compounds exhibit recovery rates ranging from 70.0 % to 130.0 %. Furthermore, we apply our method to analyze a real water sample, successfully identifying over 100 target and nontarget VOCs/SVOCs, including alcohols, aldehydes, ketones, acids, esters, and phenols. These results highlight the efficacy of the proposed analysis system, capable of conducting two distinct analyses in automatic sequence, thereby enhancing the efficiency and accuracy of organic compound analysis in water matrices. [ABSTRACT FROM AUTHOR]

• Analysis of the monomer composition HPMC by LC × LC-MS. • Separation of the monomers based on the number and position of the substituents. • Identification of constitutional isomers through LC × LC-MS/MS. • Comparison of the two industrial samples with the same average substitution. Hydroxypropyl methyl cellulose (HPMC) is a type of cellulose derivative with properties that render it useful in e.g. food, cosmetics, and pharmaceutical industry. The substitution degree and composition of the β-glucose subunits of HPMC affect its physical and functional properties, but HPMC characterization is challenging due to its high structural heterogeneity, including many isomers. In this study, comprehensive two-dimensional liquid chromatography-mass spectrometry was used to examine substituted glucose monomers originating from complete acid hydrolysis of HPMC. Resolution between the different monomers was achieved using a C18 and cyano column in the first and second LC dimension, respectively. The data analysis process was structured to obtain fingerprints of the monomers of interest. The results revealed that isomers of the respective monomers could be selectively separated based on the position of substituents. The examination of two industrial HPMC products revealed differences in overall monomer composition. While both products contained monomers with a similar degree of substitution, they exhibited distinct regioselectivity. [ABSTRACT FROM AUTHOR]

• Heteroatoms are in fuel at low levels, but can significantly affect fuel properties. • Hydrophilic interaction liquid chromatography is a powerful separation technique. • Hydrophilic interaction liquid chromatography can identify heteroatoms in jet fuel. • Chromatographic conditions and nature of the injection sample have significant effect. Aviation turbine fuel is a complex mixture of thousands of compounds. An analytical method using hydrophilic interaction liquid chromatography (HILIC) coupled with electrospray ionization and quadrupole time-of-flight mass spectrometry (ESI-QTOF) was developed for the identification of heteroatomic, polar compounds in aviation turbine fuel. Although compounds containing oxygen, nitrogen, and sulfur functional groups are each found at low levels (<0.1 % by mass) in fuels, their presence can generate significant effects on fuel properties. The HILIC-ESI-QTOF method is a combined separation and detection technique that possesses many advantages including a fast and simple sample preparation—requiring no extraction step therefore ensuring no loss of compounds of interest—and the ability to acquire high-fidelity compound data for chemometric analysis of heteroatomic species in aviation turbine fuel. In the development of the method, it was found that the chromatographic conditions and nature of the injection sample had a significant effect on separation efficiency and repeatability. For a sample dataset optimized using a singular aviation turbine fuel, retention time shift was able to be reduced from 0.4 min to 2.0 % relative standard deviation (RSD) to approximately 0.1 min with RSD of 0.4 % using the newly developed method. In addition, a high number of untargeted molecular features (944) and targeted amines (121) were able to be identified when utilizing optimal method conditions. The specific benefits and limitations of utilizing HILIC techniques with HPLC-ESI-QTOF are also discussed herein. This new method is currently being expanded to include analysis of all heteroatoms and is being applied to real fuel sets. The results of these studies are forthcoming. [ABSTRACT FROM AUTHOR]

• We report an integral strategy for exploring the mechanism of PLE in the treatment of MI. • A total of 77 components were characterized from PLE using UPLC-Q-TOF–MS. • PLE improves arginine metabolism and intestinal flora disorder thereby ameliorating MI. • Metabolites and intestinal microbiota were identified and characterized. The extraction methods for traditional Chinese medicine (TCM) may have varying therapeutic effects on diseases. Currently, Pueraria lobata (PL) is mostly extracted with ethanol, but decoction, as a TCM extraction method, is not widely adopted. In this study, we present a strategy that integrates targeted metabolomics, 16 s rDNA sequencing technology and metagenomics for exploring the potential mechanism of the water extract of PL (PLE) in treating myocardial infarction (MI). Using advanced analytical techniques like ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), we comprehensively characterized PLE's chemical composition. Further, we tested its efficacy in a rat model of MI induced by ligation of the left anterior descending branch of the coronary artery (LAD). We assessed cardiac enzyme levels and conducted echocardiograms. UPLC-MS/MS was used to compare amino acid differences in serum. Furthermore, we investigated fecal samples using 16S rDNA sequencing and metagenomic sequencing to study intestinal flora diversity and function. This study demonstrated PLE's effectiveness in reducing cardiac injury in LAD-ligated rats. Amino acid metabolomics revealed significant improvements in serum levels of arginine, citrulline, proline, ornithine, creatine, creatinine, and sarcosine in MI rats, which are key compounds in the arginine metabolism pathway. Enzyme-linked immunosorbent assay (ELISA) results showed that PLE significantly improved arginase (Arg), nitric oxide synthase (NOS), and creatine kinase (CK) contents in the liver tissue of MI rats. 16 s rDNA and metagenome sequencing revealed that PLE significantly improved intestinal flora imbalance in MI rats, particularly in taxa such as Tuzzerella, Desulfovibrio, Fournierella, Oscillibater, Harryflintia, and Holdemania. PLE also improved the arginine metabolic pathway in the intestinal microorganisms of MI rats. The findings indicate that PLE effectively modulates MI-induced arginine levels and restores intestinal flora balance. This study, the first to explore the mechanism of action of PLE in MI treatment considering amino acid metabolism and intestinal flora, expands our understanding of the potential of PL in MI treatment. It offers fresh insights into the mechanisms of PL, guiding further research and development of PL-based medicines. [ABSTRACT FROM AUTHOR]

• This review highlights the recent advances of nanomaterial-based matrices for matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). • Then, it addresses the potential applications, advantages and disadvantages of various matrix. • Finally, it gives the perspectives on future exploration in nano-matrix. Matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a novel soft ionization bio-mass spectrometry technology emerging in the 1980s, which can realize rapid detection of non-volatile, highly polar, and thermally unstable macromolecules. However, the analysis of small molecular compounds has been a major problem for MALDI-TOF MS all the time. In the MALDI analysis process based on traditional matrices, large numbers of interference peaks in the low molecular weight area and "sweet spots" phenomenon are produced, so the detection method needs to be further optimized. The promotion of matrix means the improvement of MALDI performance. In recent years, many new nanomaterial-based matrices have been successfully applied to the analysis of small molecular compounds, which makes MALDI applicable to a wider range of detection and useful in more fields such as pharmacy and environmental science. In this paper, the newly developed MALDI matrix categories in recent years are reviewed initially. Meanwhile, the potential applications, advantages and disadvantages of various matrices are analyzed. Finally, the future development prospects of nanomaterial-based matrices are also prospected. [ABSTRACT FROM AUTHOR]

• Characterisation of PP aerosol of heated tobacco product by TD-GC × GC-TOFMS/FID. • Reliable peak finding procedure for non-targeted analysis of GC × GC chromatograms. • Comparison of PP of heated tobacco product (THP1.0) and a combustible product. • Semi-quantification of compounds identified in PP. An analytical methodology based on thermal desorption and comprehensive two-dimensional gas chromatography with dual time-of-flight mass spectrometry and flame ionization detection (TD-GC × GC-TOFMS/FID) has been developed for non-target analysis of volatile organic compounds (VOCs). The technique was optimised for the measurement of the VOC content of the particulate phase (PP) fraction of aerosols produced by a tobacco heating product (THP1.0) and 3R4F mainstream tobacco smoke (MTS). The method involves sampling the PP fraction on quartz wool packed in a sorbent tube directly connected to machine-puffing, followed by a dilution through a TD recollection procedure over Tenax/Sulficarb sorbent before TD-GC × GC-TOFMS/FID analysis. The comparison of the VOC content of the PP fraction of aerosols produced by THP1.0 and MTS highlighted the compositional difference between tobacco combustion (592 peaks) and tobacco heating process (160 peaks). Mass spectrometric signals were used for qualitative analyses based on linear retention indices, mass spectral matches, and GC × GC structured chromatograms, which collectively identified up to 90% of analytes detected in PP samples. FID signals were used for semi-quantitative analyses based on a chemical class external calibration method. The global chemical composition of PP samples showed that hydrocarbons, oxygenated, and nitrogen-containing compounds were fewer in number and much less abundant in THP1.0 PP. Overall, 93 compounds were common to the two sample types. Excepted for a few highly volatile compounds (mainly furan family) as well as glycerine and its acetate, analyte concentrations were higher in MTS PP. [ABSTRACT FROM AUTHOR]

• 2D LC/UHPSFC-Q-TOF-MS system was established for characterization. • GNPS was applied for dereplication with high efficiency and accuracy. • A mass of isomers were separated and exposed. • Two subclasses compounds were found for the first time. • Two new bufadienolides were identified to verify the strategy. Comprehensive analysis and identification of chemical components are very important to evaluate the efficacy and safety of traditional Chinese medicine (TCM). Meanwhile, the discovery of new natural compounds is of great significance for drug exploitation and development. Although two-dimensional liquid chromatography (2D LC) systems expand the peak capacity and improve selectivity and resolution, interpreting the post-processing data is tedious and time-consuming. In this study, an off-line two-dimensional liquid chromatography/ultra-high performance supercritical fluid chromatography tandem quadrupole time-of-flight mass spectrometry (2D LC/UHPSFC-Q-TOF/MS) system was established for systematic chromatographic separation and identification of bufadienolides. Subsequently, the Global Natural Product Social Molecular Networking (GNPS) was applied for dereplication of chemical components of adjacent fractions with high efficiency and accuracy. The key parameters which affected separation and detection with respect to chromatographic conditions and mass spectrometry conditions were optimized. The extract of Venenum Bufonis was fractionated into forty fractions by first-dimensional reversed phase high-performance liquid chromatography (HPLC), which were further analyzed by the second-dimensional UHPSFC-Q-TOF/MS in positive ion mode. The data of forty fractions was imported into GNPS and processed automatically within about five hours. Furthermore, the chemical components with similar featured fragments were classified into the same cluster, which was helpful for components identification. A total of 229 bufadienolides were characterized and two subclasses of compounds (bufogenins conjugated with carboxylic acid and N -heterocyclic bufogenins) were found in Venenum Bufonis for the first time. In addition, UHPSFC exhibited powerful separation ability of isomers in Venenum Bufonis. In this analysis, two new compounds were isolated and fully characterized by NMR verifying the feasibility of this combined analytical strategy. This integrated strategy can improve the efficiency in the detection of new compounds and offer greater observation of isomers from medicinal herbs and other natural sources. [ABSTRACT FROM AUTHOR]

• PRE enhanced MS strategy was established to identify the constituents of DHI. • The integrated strategy helped systematical and rapid identification. • Precursor ion scans after fragmentation study improved detection ability of MS. • 90 constituents were tentatively identified in DHI. Danhong injection (DHI) is a Chinese Material Medical standardized traditional Chinese medicine injection (TCMI) used for the treatment of coronary heart disease and cerebral ischemia. The present study aims to describe and exemplify an UPLC-QTrap based integrated strategy enhanced by precursor ion (PRE) scan, to systematically and rapidly identify the chemical constituents of DHI. After untargeted EMS-IDA-EPI scan, fragmentation study of representative components and focused PRE scans, 90 compounds were tentatively identified. Compared with the single full scan, the presented strategy provided high sensitivity to phenolic compounds with the help of PRE scan mode and QqQ instrument. Considering the abundant phenolic contents in DHI, the established strategy was designed to give sensitive and systematic characterization of phenolic constituents. The results may provide more information to help illustrate the relationship between the complicated constituents and the therapeutic effects of DHI. This strategy may also be applied in researches on other traditional Chinese medicine products. [ABSTRACT FROM AUTHOR]

• MSPD coupled with UHPLC-Q-TOF/MS was used to determine organic acids in fruit. • Calix[8]arene was used as an efficient sorbent in MSPD procedure. • The ionic liquids were applied as extraction solvents. • The proposed method was rapid, simple, low cost and high sensitivity. A rapid and effective method was successfully established for the extraction and determination of chlorogenic acid, protocatechuic acid, malic acid, caffeic acid and gallic acid in fruit (chaenomeles speciosa) via matrix solid-phase dispersion (MSPD) microextraction combined with ultra-high performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF/MS). Several major extraction parameters were investigated and optimized, such as the type of sorbent, the amount of sorbent, the grinding time, the type and concentration of the eluting solvent. The optimal extraction conditions were obtained by using 20 mg of calix[8]arene as dispersing adsorbent, selecting 60 s as the appropriate grinding time and applying 250 mM of 1-dodecyl-3-methylimidazolium bromide as eluent solvent. Moreover, the calibration curves of the analytes were in the range of 0.01–500 μg/mL with the determination coefficients (r2) higher than 0.9995. The limits of detection and limits of quantification were in the range of 0.202–1.056 ng/mL and 0.674–3.521 ng/mL, respectively. The recoveries of the target compounds at two spiked levels were between 82.19 and 113.36%. Furthermore, this method had acceptable reproducibility (RSD ≤ 3.84%). The proposed approach combined the advantages of MSPD microextraction with UHPLC-Q-TOF/MS, and could be applicable for the analysis organic acids in fruit. [ABSTRACT FROM AUTHOR]

• A structure-diagnostic ions-oriented network was proposed for the identification of constituents. • Comprehensive chemical analysis of YDXNT was carried out based on LC–MS and GC–MS. • A total of 124 constituents were identified, and 67 constituents were quantified. • 16 compounds was identified as the effective combinational components of YDXNT in vitro. Discovering effective combinational components (ECCs) and quality control markers of TCMs is still facing challenges because the holistic healing system comprises hundreds of compounds. Here, taking Yindan Xinnaotong soft capsule (YDXNT), a TCMs preparation composed by 8 herbs, as a case, a strategy that integrated multiple chromatographic analysis and bioactivity assay was proposed for potential ECCs of neuroprotection discovery. Firstly, ultra-high performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF MS) and gas chromatography-mass spectrometry (GC–MS) were applied for comprehensive profiling of the chemical constituents in YDXNT. Given the fact that the complex matrix interference makes it more difficult to identify potentially active compounds, we proposed a structure-diagnostic ions-oriented strategy to remove interference ions from the raw UHPLC-MS data. The proposed strategy consisted of different filtering methods, including diagnostic fragment ions filtering (DFIF), mass defect filtering (MDF) and neutral loss (NL). Using this strategy, a total of 124 compounds were rapidly identified. Among them, 62 non-volatile and 5 volatile constituents in 30 batches of YDXNT were quantified by UHPLC tandem triple quadrupole mass spectrometry (QQQ-MS) and GC–MS methods, respectively. In order to facilitate the quality control of YDXNT, candidate ECCs were selected based on the threshold setting of absolute -contents, and their neuroprotective effects were examined. Finally, a combination of 16 compounds, accounts for 2.80% (w/w) of original YDXNT, was identified as its potential ECCs, which could be considered for the improvement of quality standardization of YDXNT. [ABSTRACT FROM AUTHOR]

• The analytical method is evaluated using the statistical model of overlap. • Analyte discovery depends on chromatogram saturation and mass spectral similarity. • A minimum chromatographic resolution of 0.05 for analyte discovery was observed. • Chemometric deconvolution is assisted by the analytical method. Evaluation of a recently developed data reduction method for gas chromatography time-of-flight mass spectrometry (GC-TOFMS) is presented in the context of the statistical model of overlap (SMO) using simulated chromatographic data. The two-dimensional mass cluster plot method (2D m / z cluster plot method) significantly improves separation visualization by measuring the retention time, t R , and peak width-at-base, w b , of each analyte peak on a per mass channel, m / z , basis and plotting w b versus t R as a single point for each peak. Additional selectivity is provided by the peak width dimension, allowing for the differentiation of "pure" or selective m / z and shared or overlapped m / z. Analyte clusters in the 2D mass cluster plot are defined based on clustering of individual points, representing the selective m / z for those analytes, and encompassed by a box of user-specified size. The method is applied to simulated chromatographic data with a random, independent distribution of analyte peaks and constant peak w b. Two levels of chromatographic saturation factor, α , and two sets of analyte mass spectra with varying spectral similarity are studied to assess method performance. The percentage of analyte clusters found relative to the number of analytes simulated in the chromatogram increases as the box size (analogous to chromatographic resolution, R s) is decreased, resulting in an R s limit of 0.05 for the method. Additionally, the percentage of analyte clusters discovered also increases with lower α and greater dissimilarity between analyte mass spectra, demonstrating the immense benefit of improving the chromatographic separation and chemical selectivity in analyte discovery, identification, and quantification. [ABSTRACT FROM AUTHOR]

• 21 volatile NIAS were determined in a novel starch-base biopolymer. • Migration assays of prototype samples were performed. • Two different mass spectrometry ionization techniques were used. • Atmospheric Pressure Gas Chromatography was found complementary to Electron Ionization. • Recent advances in ionization pathways were applied to structural elucidation. The rapid growth of polymer technology in the field of food contact materials (FCMs) needs to be supported by continuous improvement in material testing, in order to ensure the safety of foodstuff. In this work, a range of different starch-based biopolymer samples, in the shape of pellets and retail samples (cups and dishes) were studied. The optimized extraction process was performed on three different pellet shapes: pellets with no modification (spherical), pellets shattered under high pressure (lentils), and pellets cryogenically ground (powder). The analysis of unknown volatile and semi-volatile compounds was carried out by gas chromatography-mass spectrometry, using both electron ionization with a single quadrupole mass analyzer (GC-EI-MS), and atmospheric pressure gas chromatography with a quadrupole/time of flight mass analyzer (APGC-Q/ToF). The identification process was implemented using the latest advances in the understanding of APGC ionization pathways. Chemical migration was also assessed on prototype samples using the food simulants: ethanol 10% v/v, acetic acid 3% w/V, ethanol 95% v/v, isooctane, and vegetable oil. Each migration test was performed three consecutive times, as recommended for materials intended for repeated use. [ABSTRACT FROM AUTHOR]

• A new discriminating metabolite isomerism strategy was developed. • Metabolome of L. japonicus and L. cardiaca were elucidated. • 257 compounds and 67 pairs of isomers were characterized and identified. • 56 characteristic markers were discovered to discriminate these two species. The isomer structural discrimination is a significant challenge in metabolome analysis based on ultrahigh performance liquid chromatography tandem high-resolution mass spectrometry (UHPLC-HRMS). In this study, a new discriminating metabolite isomerism strategy is proposed to elucidate the metabolome, especially the isomers, of Leonurus japonicus and Leonurus cardiaca. This strategy consists of three steps. First, the metabolite biosynthesis pathways are constructed based on a home-built compound database to rapidly profile the compounds of interest using the multiple diagnostic product ions (DPIs) screening analysis and binary comparison based on SUMPRODUCT function. Second, the fragmentation patterns (e.g. the high-resolution DPIs, DPI ratios) and chromatographic elution order are defined based on scattered reference chromatographic and mass spectrometry data, calculated lipophilicity parameters, molecular hydrogen bond analysis, and chemical reference standards. Finally, all discovered isomerisms are mapped with the defined applicable rules and the isomers are identified conveniently. Using this strategy, a total of 257 compounds were tentatively characterized, including 212 potential novel compounds and 67 pairs of cis -, trans -, and positional isomers of flavonoids, phenylethanoid glycosides, glucaric acids, novel quinic acids, and esters of fatty acids. Moreover, 56 characteristic markers were identified to discriminate these two herbal medicines. This strategy may significantly improve the efficiency and reliability of identifying isomers found in metabolite biosynthesis pathways. [ABSTRACT FROM AUTHOR]

• Unassisted stoichiometric degradation of DOSS to monooctyl sulfosuccinate 2 (MOSS). • LC/QToF method for DOSS and MOSS as dual tracers for oil spill dispersant. • Dispersant plus dilbit in seawater microcosm study of DOSS conversion to MOSS. • Extension of environmental seawater sample collection time. A high resolution mass spectrometry method was developed for the environmental impact monitoring of oil spill dispersants. Previously reported instability of dioctyl sulfosuccinate (DOSS) dispersant tracer was addressed by the new procedure. The method monitors both DOSS and its degradation product, monooctyl sulfosuccinate (MOSS), by liquid chromatography time-of-flight mass spectrometry. The related isomer, 4-(2-ethylhexyl) 2-sulfobutanedioate, was chromatographically resolved from MOSS but was not a product of DOSS degradation. Using this direct injection method (10 μL), the practical lower limit of quantitation was 0.5 nM for each analyte, a concentration equivalent to 0.22 ng mL−1, or 0.30 ng mL−1 including initial dilution factor with acetonitrile. The method was shown applicable to analysis of the dispersants Corexit® EC9500 A, Finasol OSR 52, Slickgone NS, and Slickgone EW for which DOSS is an active ingredient. A marine microcosm study of Corexit EC9500A, together with diluted bitumen (dilbit), at 15 ± 1 °C, provided evidence of the stoichiometric conversion of DOSS to MOSS under conditions reflecting a western Canadian marine environment. The advantage of the developed method is in its ability to extend environmental seawater sample collection time from 4 days for DOSS alone, to 14 days when both DOSS and MOSS are simultaneously analysed and results combined. The collection time is likely extended beyond the 14 day period with cooler temperatures. Preservation of collected seawater samples using sodium hydroxide, converting DOSS into MOSS in situ , was rejected due to stability issues. Addition of disodium ethylenediaminetetraacetic acid did not improve hold times, thus eliminating the theory of cation induced micelle effects causing DOSS loss. [ABSTRACT FROM AUTHOR]

• New routine capabilities to speciate complex gas-phase organic mixtures in air. • Dual MS setup combines hard electron ionization and soft chemical ionization. • High-resolution MS coupled to our integrated sampling-to-analysis system. • Characterizes complex mixtures of both primary and functionalized compounds. • Tandem mass spectrometry (MS/MS) enables isomer structural characterization. Complex airborne mixtures of organic compounds can contain 10,000′s of diverse compounds at trace concentrations. Here, we incorporate high-resolution mass spectrometry into our integrated offline sampling-to-analysis measurement system for routine molecular-level speciation of complex mixtures in gas- or particle-phase samples with detection limits of 2–20 pg L−1 (i.e. 0.2–1.9 ppt in 6 L samples). Analytes desorbed from custom adsorbent tubes (or filter extracts) were separated via gas chromatography (GC) and simultaneously analyzed by an electron ionization quadrupole mass spectrometer (EI-MS), and by atmospheric pressure chemical ionization (APCI) combined with a high-resolution quadrupole time-of-flight mass spectrometer (Q-TOF) with a resolution of 25,000–40,000 M/ΔM in HR-TOF and MS/MS modes. We demonstrated our system with simple standards, a Macondo crude oil standard as a reference for complex mixtures of common airborne compounds, and ambient samples using GC-TOF and GC–MS/MS. We speciated complex mixtures at mass accuracy error (i.e. mass tolerance) down to 8 ± 2 ppm (e.g. resolving analytes of mass 270.000 u with 0.003 u accuracy) using a targeted approach with 3000 molecular formulas, including hydrocarbons and functionalized analytes containing oxygen, sulfur, nitrogen, or phosphorous. This extended from compounds with 10 to 32 carbon atoms and up to 16 hydrocarbon formulas per carbon number, and a similar range for functionalized compound classes. We also demonstrated our MS/MS capabilities to differentiate structural isomers and determine the presence of specific functional groups; and our direct-TOF capability, which bypasses high-temperature chromatographic separation to preserve functionalized analytes. [ABSTRACT FROM AUTHOR]

• GC×GC-TOFMS-Tandem Ionization provides accurate fingerprints of cocoa volatiles. • Tandem Ionization provides complementary information for identity confirmation. • Tandem Ionization extends the information potential of GCxGC fingerprinting. • Effective UT fingerprinting on fused data streams from tandem ionization signals. • Adding extra-dimensions to detection improves fingerprinting accuracy. The capture of volatile patterns from food is a fingerprinting that opens access to a high level of information related to functional variables (origin, processing, shelf-life etc.) and their impact on sample composition and quality. When the focus is on food volatilome, comprehensive two-dimensional gas chromatography combined with time-of-flight mass spectrometry (GC×GC-TOF MS) is undoubtedly the most effective technique to obtain a highly representative fingerprinting. A recently patented ion source, featuring variable-energy EI, when operated at low energies (10 eV, 12 eV, 14 eV), claims enhanced intensity of structure-indicating ions while minimizing the inherent loss of sensitivity due to low EI energies. The spectral acquisition is done by multiplexing between two ionization energies and generates tandem data streams in a single run. This study explores the potentials of combined untargeted/targeted (UT) fingerprinting with tandem signals to study the complex volatile metabolome of high quality cocoa. The quality of the spectra at 70 eV is confirmed by similarity match factors above a fixed threshold (950) while spectral differences between hard (70 eV) and soft (12 eV, 14 eV) ionization are computed in terms of spectral similarity and signal-to-noise ratio (SNR). Tandem signals are then processed independently and after fusion in a single stream (summed signal) by the UT fingerprinting work-flow; signal characteristics (SNR, detectable 2D peaks, spectral peak intensities) are then computed and adopted to define the best strategy to discriminate and classify samples. Classification performance, on processed cocoa from four different origins, is validated by cross-comparing results between single ionization channels and fused data streams and considering both targeted and untargeted features. Classification results indicate the potential for superior performances of UT fingerprinting with fused data streams (summed signals), while signal characteristics at low ionization energies not only offer additional elements to better discriminate and/or identify isomeric analytes but also to achieve wider dynamic range of exploration. [ABSTRACT FROM AUTHOR]

• A series of separation techniques guided by sensory evaluation were used. • Two peptides with umami taste were identified in Volvariella volvacea. • Taste characteristics and dose-response relationships of peptides were studied. Mushroom peptides produced by high-pressure cooking from Volvariella volvacea were found to retain and enhance the umami taste. Three tasty peptides were identified as Ala-Ser-Asn-Met-Ser-Asp-Leu (ASNMSDL), Tyr-Tyr-Gly-Ser-Asn-Ser-Ala (YYGSNSA) and Leu-Gln-Pro-Leu-Asn-Ala-His (LQPLNAH) by UPLC-Q-TOF-MS, after a series of separation methods of ultrafiltration, gel filtration chromatography and reverse phase high-performance liquid chromatography. Each fractionation step is based on the results of sensory evaluation. ASNMSDL and LQPLNAH have umami taste with threshold values of 10.19 and 12.63 mmol/L, respectively. In addition, these two peptides also showed umami-enhancing properties with a threshold estimated at 13.58 and 18.95 mmol/L, respectively. Furthermore, the peptides showed better sensory taste than mixtures of their constituent amino acids. After separation and purification, the content of taste peptides in Volvariella volvacea is about 1.4%. [ABSTRACT FROM AUTHOR]

• SWATH is able to provide MS/MS of more compounds than IDA. • The quality of the MS/MS spectra is lower in SWATH than in IDA. • No significant differences between FSWATH and VSWATH were appreciated. • Several pharmaceuticals were detected in mussel samples. • Several pesticides, pharmaceuticals and PCPs were detected in sediment samples. The aquatic ecosystems are dynamic environments often affected directly or indirectly by a myriad of anthropogenic contaminants that need to be properly identified. In this study, liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QqTOF-MS) suspected-screening was applied to mussels and riverine sediment both, non-spiked and spiked with a mixture of 32 pharmaceuticals. Three data acquisition methods sequential window acquisition of all theoretical fragment-ion spectra (SWATH), in fix (FSWATH) and variable (VSWATH) window modes and Information Dependent Acquisition (IDA) were compared to determine the most suitable acquisition technique. The results obtained in the spiked samples showed that the two SWATH modes enable to obtain the MS/MS spectrum of a higher number of compounds (up to 27 with FSWATH and 25 with VSWATH) than IDA (up to 19) in sediment and mussel. The different data acquisition modes were also tested in non-spiked samples to verify the results obtained in the spiked ones. Importantly, all the methods are able to detect the MS/MS spectrum of several contaminants in the samples when analysed against a database of >600 compounds. Up to 7 contaminants were tentatively detected with IDA, 15 with FSWATH and 17 with VSWATH. Most pollutants were pesticides and pharmaceuticals, being of particular interest the presence of ibuprofen and acetaminophen in mussels. [ABSTRACT FROM AUTHOR]

• Powerful analytical strategy for food by-products valorization. • Green PLE procedure in two steps to recover lipidic and phenolic fractions. • Metabolites profiling of obtained PLE fractions by LC/GC-q-TOF-MS(/MS). • HRMS data-mining approaches for systematic detection of secondary metabolites. An integrated analytical methodology based on pressurized-liquid extraction (PLE) in two steps, followed by in vitro assays and liquid chromatography/gas chromatography coupled to high-resolution mass spectrometry (HRMS), was developed and applied for the isolation and characterization of potential bioactive metabolites from Passiflora mollissima seeds. PLE was proposed in two sequential steps: 1) recovery of the lipidic fraction using nonpolar solvents, and 2) recovery of the phenolic fraction from the defatted seeds' residue using polar solvents. Cyclohexane was selected as the most suitable extraction solvent for the seeds defatting process (20 min, 100 °C and 100 bar). PLE optimization by response surface methodology was carried out to obtain phenolics-rich extracts with the highest antioxidant activity. Optimal extraction yield (6.58%), total phenolic content (29.99 mg g−1), total flavonoids content (0.94 mg g−1) and antioxidant activity (6.94 mM trolox g-1 and EC 50 of 2.66 μg mL−1) were obtained operating at 150 °C with EtOH (100%) as solvent. Untargeted and semi-targeted MS and MS/MS data-mining strategies were successfully implemented for the rapid and comprehensive profiling of the polar and lipidic PLE fractions analysed by UHPLC and GC, respectively, coupled to quadrupole time-of-flight mass spectrometry (q-TOF-MS/MS). Polyphenols-rich extracts from P. mollisima seeds were characterized for the first time applying this approach, showing a broad variety of flavonoids, genuine flavanols (e.g. (epi)fisetinidol) and abundant proanthocyanidins. This application can be considered a successful demonstration of the great potential of the proposed methodology to effectively obtain and characterize complex natural extracts with potential bioactivity, by making use of powerful integrated identification strategies to facilitate the challenging post-acquisition data processing of huge datasets generated by HRMS analysis. [ABSTRACT FROM AUTHOR]

Highlights • Ability and reliability of six methods to recover lipids from artery were evaluated. • A dichloromethane-based extraction method was the most efficient one. • Lipids were separated by class, identified and quantified by UHPSFC/QTOF-MS/MS. • The extraction method affects fragmentation of monoacylglycerols in the ion source. Abstract Pulmonary artery grafts are needed as cardiovascular bioprosthetics. For successful tissue recellularization after transplantation, lipids have to be removed from the donor artery. Developing a selective process to remove lipids without damaging the extracellular matrix greatly depends on knowing the amount and type of lipid compounds in the specific tissue. Here we present an efficient methodology for the study of lipids present in porcine pulmonary arteries. The performance of six extraction methods to recover lipids from artery was evaluated. For this purpose, a supercritical fluid chromatography method coupled to quadrupole time-of-flight mass spectrometry detection (UHPSFC/QTOF-MS) was adapted. The method enabled separation of lipids of a wide range of polarity according to lipid class in less than 7 min. One dichloromethane-based extraction method was shown to be the most efficient one for the recovery of lipids from pulmonary artery. However, one MTBE-based extraction method was able to show the highest fatty acid extraction yields (to the expense of longer extraction times). Lipids were relative quantified according to class, and the major species within each class were identified. Triacylglycerols and glycerophospholipids were the most abundant classes, followed by sphingomyelins, monoacylglycerols and fatty acyls. The matrix effect exerted no interference on the analytical method, except for some few combinations of extraction method and lipid class. These results are of relevance for lipidomic studies from solid tissue, in particular for studies on pulmonary and cardiovascular diseases. Finally, our work sets the basis for the further development of a selective processes to remove lipids from pulmonary artery without damaging the tissue prior to transplantation. [ABSTRACT FROM AUTHOR]

Highlights • Cress was grown hydroponically in water contaminated (spiked) with three statins. • More than 45 drug related compounds could be detected in plant extracts. • Combining chromatographic and spectrometric information, structures were proposed. • Metabolite concentration, distribution and metabolite persistence were investigated. • Metabolites can be detected in plants treated with drugs at very low concentrations. Abstract This work describes the metabolization of three different statins (lipid-lowering drugs) namely Atorvastatin, Fluvastatin and Simvastatin in the model plant cress (Lepidium sativum) after uptake from the growing medium. Analyzing plant extracts with HPLC hyphenated with a drift-tube ion-mobility quadrupole time-of-flight / mass spectrometer allowed the identity confirmation of more than 45 metabolites, resulting from oxidation/dehydrogenation, dehydration or hydroxylation of the parent drug or conjugation with amino acids and sugars. Metabolites were characterized by their retention times, m/z ratios, fragmentation patterns in MS/MS experiments, and their collision cross sections. Furthermore, a targeted analysis method for the trace-level analysis of the parent drugs as well as their metabolites in plant extracts was implemented by using HPLC coupled to triple quadrupole mass spectrometry in the multiple reaction monitoring mode. This approach was applied to study the metabolite distribution within the plant and to detect relative changes in metabolite concentrations as a function of growth time. Using a modified QuEChERS approach for extraction more than 50% of the metabolites could be still detected, if plants were exposed to only 1–10 μg L−1 of each statin. [ABSTRACT FROM AUTHOR]

Highlights • MAO-A was immobilized on MBs for the first time. • The MAO-A-MBs based screening method was successfully applied to screen inhibitors. • Seven ligands with MAO-A binding affinities were fished out from Corydalis Rhizome. Abstract Monoamine oxidase-A (MAO-A) is considered an important therapeutic target in depression. In order to rapidly screen and identify novel MAO-A inhibitors from natural products, a magnetic bead (MB) based drug discovery tool was developed in this study. MAO-A was first immobilized onto the surface of MBs, and the resulting MAO-A-immobilized MBs (MAO-A-MBs) were then applied to ligand fishing by combining them with high-performance liquid chromatography (HPLC) coupled with quadrupole time-of-flight tandem mass spectrometry (Q-TOF-MS/MS). The inherent catalytic activity and kinetic parameters of the immobilized-MAO-A were determined by measuring the peak area of the oxidation product. The immobilized MAO-A activity was found to remain over 80% after storage at 4 °C for about 7 days. Seven compounds (tetrahydrocolumbamine, protopine, jatrorrhizine, glaucine, tetrahydropalmatine, palmatine, dehydrocorydaline) with high binding affinity to MAO-A were fished out from the ethyl acetate fraction extract of Corydalis Rhizome. Their MAO-A inhibitory activity was further verified by enzymatic inhibition assay. These results show that the developed approach using MAO-A-MBs combined with HPLC-Q-TOF-MS/MS is suitable for the fast screening and identification of MAO-A inhibitors in complex mixtures. [ABSTRACT FROM AUTHOR]

Highlights • Combination of a thermogravimetry with a Thermal-Desorption-GC–MS. • New coupling enables high sample throughput through automated measurements. • Complex decomposition gases can be analyzed in detail by fractionated analysis. • Fast and easy determination of polymer contents in blends. • Fast analysis of microplastics in environmental samples within 2–3 h. Abstract The TED-GC–MS analysis is a two-step method. A sample is first decomposed in a thermogravimetric analyzer (TGA) and the gaseous decomposition products are then trapped on a solid-phase adsorber. Subsequently, the solid-phase adsorber is analyzed with thermal desorption gas chromatography mass spectrometry (TDU-GC–MS). This method is ideally suited for the analysis of polymers and their degradation processes. Here, a new entirely automated system is introduced which enables high sample throughput and reproducible automated fractioned collection of decomposition products. The fractionated collection together with low temperatures reduces the risk of contamination, improves instrumental stability and minimizes maintenance efforts. Through variation of the two main parameters (purge gas flow and heating rate) it is shown how the extraction process can be optimized. By measuring the decomposition products of polyethylene it is demonstrated that compounds with masses of up to 434 Da can be detected. This is achieved despite the low temperature (˜40 °C) of the solid-phase adsorber and the low thermal desorption temperature of 200 °C in the TDU unit. It is now shown that automated TED-GC–MS represents a new flexible multi-functional method for comprehensive polymer analyses. Comparable polymer characterization was previously only achievable through a combination of multiple independent analytical methods. This is demonstrated by three examples focused on practical challenges in materials analysis and identification: The first one is the analysis of wood plastic composites for which the decomposition processes of the polymer and the bio polymer (wood) could be clearly distinguished by fractionated collection using sequential adsorbers. Secondly, a fast quantitative application is shown by determining the weight concentrations of an unknown polyolefin blend through comparison with a reference material. Additionally, the determination of microplastic concentrations in environmental samples is becoming an increasingly important analytical necessity. It is demonstrated that with TED-GC–MS calibration curves showing good linearity for the most important precursors for microplastic, even complex matrix materials (suspended particulate matter) can be successfully analyzed. [ABSTRACT FROM AUTHOR]

Highlights • Off-line multi-hyphenated methods to screen iNOS inhibitors were developed. • Two types of ingredients in Radix Ophiopogonis were obtained as iNOS ligands. • Three Ophiopogonins were confirmed with obvious iNOS inhibitory activities. Abstract Off-line multi-hyphenated methods including affinity-ultrafiltration mass spectrometry, molecular docking, and reverse-phase high-performance liquid chromatography-fluorescence detection (RP-HPLC-FD) were used to rapidly screen and identify natural inducible nitric oxide synthase (iNOS) inhibitors isolated from Ophiopogon japonicus (Thunb.) Ker-Gawl. Ultrafiltration high-performance liquid chromatography quadrupole time-of-flight mass spectrometry was used to screen and identify the potential ligands with high binding affinity to iNOS. Seven compounds (three saponins and four flavonoids) were found in Radix Ophiopogonis. Molecular docking identified the binding sites and found that the binding affinity of the three ophiopogonis ligands was higher than that of the four homoisoflavonoids. Pre-column derivatization of l -citrulline and RP-HPLC-FD verified that the in vitro inhibition activity of the three ophiopogonis compounds was stronger than that of the four homoisoflavonoids, which was similar to the screened results. In conclusion, combining an in vitro iNOS inhibition assay and affinity-ultrafiltration mass spectrometry with molecular docking was a powerful tool for rapid screening and identification of iNOS inhibitors isolated from this traditional Chinese medicine. [ABSTRACT FROM AUTHOR]

Highlights • SWATH acquisition increases the analytical performance in identification/quantitation. • Narrower isolation mass windows facilitate the analysis of complex matrices. • 10 mass isolation windows were enough for a correct identification of 141 compounds. • The ion ratio stability with 10 windows allows its use for identification purposes. Abstract The introduction of sequential mass isolation window acquisition mode in high-resolution quadrupole time-of-flight analysers undoubtedly represents an important improvement in the MS/MS spectra obtained when working in non-target analysis. However, the advantages and limitations of this approach have not been sufficiently defined and evaluated. The present work seeks to fill this gap by considering its application in non-target multiresidue pesticide analysis. This work focuses on the called SWATH® method, which combines both MS and MS/MS acquisition, dividing the entire mass range into smaller segments for the MS/MS mode. The effect of the number of mass isolation windows, the total cycle-time lapsed, the sensitivity obtained, the MS/MS spectra quality, the ion ratio stability as well as the identification and quantification capabilities has been evaluated. The use of ten mass isolation windows for data acquisition was selected as a compromise between the required points per chromatographic peak and the reduction in interferences achieved. An identification study was carried out on 141 pesticides in 20 vegetable matrices to check the false positives and false identifications found automatically, in accordance with the criteria set out in Document No. SANTE/11945/2015. Furthermore, special attention was given to certain issues that can make correct identification difficult, such as low fragment abundance due using of a generic collision energy, the matrix influence on the collision cell, the effect of the concentration level as well as deconvolution failure and mass window width. Finally, to verify the efficiency of the optimum parameters proposed, two proficiency samples were analysed, obtaining good results. This proved the benefits in terms of identification and quantification purposes. [ABSTRACT FROM AUTHOR]

Highlights • GC × GC with TOFMS detection and a 50 ms modulation period is demonstrated. • Pulse flow valve modulation produces data with vacancy chromatography and frontal analysis principles. • Chemometric deconvolution facilitates conversion of the raw data into a traditional GC × GC format. • Excellent quantitative analysis and mass spectral identification of severely overlapped peaks is obtained. Abstract An ultrafast flow modulation period, P M of 50 ms, for comprehensive two-dimensional (2D) gas chromatography (GC × GC) with time-of-flight mass spectrometry (TOFMS) detection is demonstrated, producing narrow peak widths, 2 W (4σ width-at-base on the 2D dimension), demonstrating the potential for ultrafast (2D) separations with high peak capacity. The modulator is a pulse flow valve that injects a narrow pulse of carrier gas at a user defined P M , at the union between the 1D and 2D columns. The raw data produced combines the properties of vacancy chromatography and frontal analysis. Deconvolution of the raw data using unconstrained multivariate curve resolution alternating least squares (MCR-ALS) analysis facilitates identification and quantification for overlapped analyte peaks. The peak profile loadings obtained from MCR-ALS are converted into traditional appearing GC × GC data through a process commonly used with frontal analysis. An 18-component test mixture at seven different injected mass levels was studied. The 2D peaks generated ranged from an 2 W of 16 to 36 ms with an average of 26 ms. At an on-column injected mass of 14 ng per analyte, an average mass spectral match value, MV, of 822 was achieved using in-house collected spectra for comparison, with an average match value RSD of 7.1%. Calibration of overlapped test analytes was evaluated using the areas of the MCR-ALS loadings, with excellent quantification demonstrated. The advancement demonstrated in modulation performance for GC × GC represents a significant decrease in P M as most commercial modulators have a minimum P M of 1 s, while maintaining the benefits of a duty cycle of essentially 1.0, which promises to enable new chemical analyzer designs, compatible with the vacuum requirements of the TOFMS detector. [ABSTRACT FROM AUTHOR]

Highlights • A 2D GC coupled to HR/TOF-MS method was developed for the analysis of PACs. • Method was used to quantify un - and substituted PACs in environmental samples. • Shortcomings of 1D relative to 2D GC separation and quantification was highlighted. • Mass spectral fragmentation patterns was used to different classes of PAC isomers. Abstract Polycyclic aromatic compounds (PACs) consists of multiple compounds and the number of theoretically possible isomers can reach into the thousands. Currently each PAC group is quantified collectively as a single group of compounds. However, individual PACs can reveal important information on how the PACs were formed and this information may be used to determine sources of PACs in environmental samples, It is hypothesized that many of the limitations with characterizing alkylated PACs with one dimensional gas-chromatography (1D GC) can be circumvented using GC × GC (two dimensional gas chromatography). Here we apply comprehensive GCxGC coupled to high-resolution time of flight mass spectrometry (GC × GC-HFTOF-MS) to aid in the separation, identification and quantitation of APACs in three environmental matrices: mussel tissue (Mytilus edulis), lubricating oil and coal. In the absence of authentic analytical standards, differences in the mass spectral fragmentation pattern of isomers were used to confirm the identity of isomers within a PAC group. The method was validated according to the EURACHEM guidelines and used to quantify a biological standard reference material (SRM 2974a). The method met all the standard method performance requirements such as trueness, precision and measurement of uncertainty and is fit for quantifying these compounds in biota. Furthermore, the method was used to identify and quantify additional PAC compounds in the SRM 2974a material which to date have not been certified. With appropriate statistical analytical tools, the described GC × GC method can be used as a tool for more robust source fingerprinting and source apportionment of PACs in the environment. [ABSTRACT FROM AUTHOR]

Highlights • Thermal desorption is a robust sample introduction tool for GC × GC-TOFMS analysis. • Thermal desorption is efficient and repeatable for the analysis of shale cores. • Data obtained by thermal desorption are comparable to Soxhlet extracted data. • Marcellus and Utica shale cores exhibit differences in hydrocarbon chemistry. Abstract Development of shale gas resources through the use of hydraulic fracturing has raised a multitude of environmental concerns and motivated research towards the understanding of shale gas systems. Previous research has demonstrated the potential of utilizing hydrocarbon distributions towards the fingerprinting of a potential environmental contamination event arising from shale gas operations. However, to apply hydrocarbon distributions from shale gas wells towards point-source identification and apportionment, a better understanding of hydrocarbon origins must be achieved. Here we present an efficient and repeatable thermal desorption method, as a sample introduction methodology for GC × GC analysis of shale rock samples that results in comparable chromatograms to those produced by solvent extraction. This novel and robust characterization technique of shale cores from Marcellus and Utica formations by thermal desorption followed by GC × GC enables the understanding of hydrocarbon speciation within the native rock with minimal sample preparation time and solvent use. The detailed shale chemistry gives insight into utilizing hydrocarbon differences towards point-source identification methodologies of environmental contamination events associated with unconventional gas development. Additionally, this analytical technique may provide a more detailed analysis of hydrocarbons than what is currently implemented in the industry to pinpoint the most advantageous areas to exploit by hydraulic fracturing, yet avoiding undesirable areas such as those with a high abundance of sulfur containing compounds. [ABSTRACT FROM AUTHOR]

• MOF-808 was successfully grown in situ on glass fabric. • The adsorbent showed good adsorption capacity for phospholipids (3.31–6.54 mg/g). • A method was developed to extract, enrich and quantify phospholipids. • A total of 206 phospholipids were detected and identified in human milk. Phospholipids (PLs) are important and complex trace lipids in milk, which have positive effects on the infants' nervous and immune system development. Herein, a new method for selective extraction of PLs using glass fabric @ MOF-808 was proposed. Based on Lewis acid-base interaction, MOF-808 containing abundant Zr-OH groups was selected as the adsorption body, and glass fabric was used as a substrate to make the adsorbent easy to remove and reuse. The influencing factors such as loading solution, extraction time, eluent and elution time were further investigated. The adsorbent showed high adsorption capacity (3.31–6.54 mg/g for PLs) and good reusability (reused at least five times). The method showed low detection limits (1.61 μg/L - 10.24 μg/L) and quantification limits (5.24 μg/L–51.21 μg/L) for eight classes of PLs. The analysis of PLs in human milk at different lactation stages by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry could obtain up to 206 PLs, indicating that the method has extremely high extraction and anti-interference capabilities. This work is the first time to introduce MOF materials to selectively extract PLs and use glass fabric as a substrate for MOF-808, which has the advantages of easy recovery and high sensitivity. It provides technical support for the discovery of more PL species and has potential applications in phospholipidomics. [ABSTRACT FROM AUTHOR]

• Establishment of intelligent chemical profiling of Chinese herbal medicine. • Full scan-preferred parent ions capture-exclusion for data acquisition. • Deep-learning reinforced mass defect filter process applied in data processing. • 276 compounds with different chemical category in naoxintong identified. A comprehensive strategy for effective identification of total constituents in Chinese patent medicine has been advanced applying full scan-preferred parent ions capture-static and active exclusion (FS-PIC-SAE) acquisition coupled with intelligent deep-learning supported mass defect filter (MDF) process, with Naoxintong capsule (NXT) as a case. Online comprehensive two-dimensional liquid chromatography (2DLC) coupled with Q-TOF-MS/MS system was established for obtaining the excellent separation and detection performance of total components, which could exhibit excellent peak capacity with 1052 and orthogonality with 0.69. In addition, a total of 901 unknown compounds could be classified into nine chemical classes rapidly and effectively, based on the intelligent deep-learning algorithm supported MDF model with 96.4% accuracy. Consequently, 276 compounds were successfully identified from NXT, especially including 44 flavonoids, 27 phenolic acids, 25 fatty acids, 17 saponins, 21 phthalocyanines, 20 triterpenes, 10 monoterpenes, 13 diterpenoid ketones, 14 amino acids, and others. It is concluded that the proposed program is an effective and practical strategy enabling the in-depth chemical profiling of complex herbal and biological samples. [ABSTRACT FROM AUTHOR]

• An efficient strategy to illustrate the chemical mechanism of HRA processed from RA. • An integrated strategy of diagnostic ions, molecular network and chemometrics. • A total of identified 226 compounds. • Linear regression analysis to compare the chemical changes due to the individual batch differences. • Potential chemical reaction mechanisms revealed by the color changes of molecular network nodes and the change of the chemical compositions. Radix Astragali (RA) is one of the most frequently used traditional Chinese medicine (TCM) in China, and honey-processed RA (HRA) is its common processing product. Thus far, their comprehensive chemical differences are not well understood. In this work, an integrated approach using Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) combined with diagnostic ions, molecular network (MN) and chemometrics was established to profile their chemical characterizations and illustrate the chemical mechanism of RA processed with honey. A total of 226 compounds were tentatively identified including 50 flavonoid glycosides, 26 flavonoid aglycone, 56 saponins, 30 organic acids, 18 amino acids, 3 coumarins and 43 other compounds, of which 33 compounds were characterized according to MN. Their chemical differences were further investigated by integrating of multivariate statistical analysis, student's t -test analysis, linear regression analysis and MN. Consequently, multivariate statistical analysis showed that the raw and processed RA were different form each other. Besides, 33 different compounds were found to be significantly altered by student's t -test analysis. Apart from this, linear regression analysis indicated 42 and 120 compounds underwent the significant varieties. The potential chemical reactions induced by honey-processing, such as possible hydrolysis reactions and isomerization reactions, were speculated based on these variations coupled the areas changes of the nodes in MN. This study provided an efficient strategy to illustrate the chemical mechanism of TCM processing. [ABSTRACT FROM AUTHOR]

• First application of cuboid-based F-ratio analysis on GC3-TOFMS data is reported. • GC3-TOFMS data shows higher analyte discoverability compared to GC × GC-TOFMS data. • Increased analyte discoverability is due to gains in peak capacity and selectivity. Comprehensive three-dimensional (3D) gas chromatography with time-of-flight mass spectrometry (GC3-TOFMS) is a promising instrumental platform for the separation of volatiles and semi-volatiles due to its increased peak capacity and selectivity relative to comprehensive two-dimensional gas chromatography with TOFMS (GC×GC-TOFMS). Given the recent advances in GC3-TOFMS instrumentation, new data analysis methods are now required to analyze its complex data structure efficiently and effectively. This report highlights the development of a cuboid-based Fisher ratio (F-ratio) analysis for supervised, non-targeted studies. This approach builds upon the previously reported tile-based F-ratio software for GC×GC-TOFMS data. Cuboid-based F-ratio analysis is enabled by constructing 3D cuboids within the GC3-TOFMS chromatogram and calculating F-ratios for every cuboid on a per-mass channel basis. This methodology is evaluated using a GC3-TOFMS data set of jet fuel spiked with both non-native and native components. The neat and spiked jet fuels were collected on a total-transfer (100 % duty cycle) GC3-TOFMS instrument, employing thermal modulation between the first (1D) and second dimension (2D) columns and dynamic pressure gradient modulation between the 2D and third dimension (3D) columns. In total, cuboid-based F-ratio analysis discovered 32 spiked analytes in the top 50 hits at concentration ratios as low as 1.1. In contrast, tile-based F-ratio analysis of the corresponding GC×GC-TOFMS data only discovered 28 of the spiked analytes total, with only 25 of them in the top 50 hits. Along with discovering more analytes, cuboid-based F-ratio analysis of GC3-TOFMS data resulted in fewer false positives. The increased discoverability is due to the added peak capacity and selectivity provided by the 3D column with GC3-TOFMS resulting in improved chromatographic resolution. [ABSTRACT FROM AUTHOR]

• A strategy for more reliable identification of herbal components was proposed. • Offline 2D-LC/IM-QTOF-MS, HDDDA-EL, and QSRR prediction of t R were included. • Enhanced exposure and characterization of minor ginsenosides from PQF was achieved. • Prediction of t R could reduce candidate identifications for isomeric ginsenosides. • 421 saponins got characterized from PQF, involving 284 new for the Panax genus. To accurately identify the metabolites is crucial in a number of research fields, and discovery of new compounds from the natural products can benefit the development of new drugs. However, the preferable phytochemistry or liquid chromatography/mass spectrometry approach is time-/labor-extensive or receives unconvincing identifications. Herein, we presented a strategy, by integrating offline two-dimensional liquid chromatography/ion mobility-quadrupole time-of-flight mass spectrometry (2D-LC/IM-QTOF-MS), exclusion list-containing high-definition data-dependent acquisition (HDDDA-EL), and quantitative structure-retention relationship (QSRR) prediction of the retention time (t R), to facilitate the in-depth and more reliable identification of herbal components and thus to discover new compounds more efficiently. Using the saponins in Panax quinquefolius flower (PQF) as a case, high orthogonality (0.79) in separating ginsenosides was enabled by configuring the XBridge Amide and CSH C18 columns. HDDDA-EL could improve the coverage in MS2 acquisition by 2.26 folds compared with HDDDA (2933 VS 1298). Utilizing 106 reference compounds, an accurate QSRR prediction model (R2 = 0.9985 for the training set and R2 = 0.88 for the validation set) was developed based on Gradient Boosting Machine (GBM), by which the predicted t R matching could significantly reduce the isomeric candidates identification for unknown ginsenosides. Isolation and establishment of the structures of two malonylginsenosides by NMR partially verified the practicability of the integral strategy. By these efforts, 421 ginsenosides were identified or tentatively characterized, and 284 thereof were not ever reported from the Panax species. The current strategy is thus powerful in the comprehensive metabolites characterization and rapid discovery of new compounds from the natural products. [ABSTRACT FROM AUTHOR]

Highlights • A specific LC-QTOF-MS method for screening of dental materials was developed. • Ammonium fluoride improves LC–MS sensitivity for dental resin ingredients. • BPA ethoxylated methacrylates (BisEMA) standards contain a variety of oligomers. • Most identified compounds were not stated on the material safety data sheets. Abstract Since 2011, the World Health Organization has encouraged a global phase-down of the use of dental amalgam and actively supported the use of alternative, resin-based dental materials. The resins consist of (meth)acrylate monomers derived from Bisphenol A (BPA), such as Bisphenol A glycidyl methacrylate (BisGMA) and Bisphenol A ethoxylate methacrylate (BisEMA) or triethylene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA) which lack the BPA backbone. Besides monomers, other compounds such as photoinitiators and stabilizing agents can be present in the dental resin matrices. The current study consists in the development of an analytical method for the separation and identification of dental material components using LC-QTOF-MS. The developed method was applied on several dental material ingredients, unpolymerized composite resins, and a common dental sealant. The acquired high resolution accurate-mass data was analyzed using suspect screening with an in-house developed library. Next to the main components, various isomers and impurities related to the production of the main component have been detected and identified in the dental material ingredients. In total, 39 chemicals have been identified in the analyzed dental materials. On average 15 chemicals have been identified. Major components, such as BisEMA, BisGMA and TEGDMA were identified although they were not always stated in the material safety data sheets. Minor components included photoinitiators, such as ethyl 4-dimethyl aminobenzoate (EDMAB) and (meth)acrylates impurities originating from production of main ingredients. [ABSTRACT FROM AUTHOR]

Highlights • A multi-residue LC-TOF-MS method is proposed in muscle tissue of European sea bass. • Confirmation of antibiotics was achieved by the QTOF-MSE approach for the first time. • The new method was fully validated according to 2002/657/EC guideline. Abstract A UPLC-QTOF-MS method for the simultaneous determination of 20 veterinary drug residues and metabolites (tetracyclines, quinolones, sulfonamides and diaminopyrimidines) in edible muscle plus skin tissue of European sea bass (Dicentrarchus Labrax) was developed. For the identification of analytes a positive electrospray ionization quadropole time-of flight mass spectrometer operating in MSE mode (UPLC-QTOF-MSE) was used. MSE mode provides high chromatographic resolution and accurate mass measurements in both MS and MS/MS modes simultaneously in a single run. Separation was achieved on a UPLC BEH C18 (50 mm × 2.1 mm, 1.7 μm) column in a gradient elution program of 10 min. Examined antibiotics were isolated easily after a simple solid-liquid extraction procedure with acidic acetonitrile (0.1% v/v formic acid) and Na 2 EDTA 0.1 M. Recovery rates from muscle plus skin tissue ranged from 93.8% to 107.5% for all targeted compounds. The detection limits and the limits of quantification ranged from 2.22 to 15.00 μg/kg, and from 6.67 to 45.46 μg/kg, respectively. The developed method was validated in terms of selectivity, matrix effect, linearity, accuracy, precision, stability and sensitivity, CCα and CCβ according to European Union Decision 2002/657/EC. The proposed method was applied for the analysis of contaminated fish samples after in feed administration of danofloxacin mesylate. [ABSTRACT FROM AUTHOR]

Highlights • The capabilities of UPLC/TWIM-TOF-MS to separate NAs isomers were investigated. • CCS values for NAs allowed identification of some alicyclic species in NAs mixture. • It is not possible to resolve all NA isomers at this current IM resolving power. • IM provides useful information about the size range of isomers in the NAs mixture. Abstract The separation of isomeric naphthenic acids (NAs) is of high importance to obtain more detailed and therefore useful information to understand their fate, transport, toxicity and potential removal treatment methodologies. In the current study, the capabilities of the ultrahigh pressure liquid chromatography/traveling wave ion mobility-time of flight mass spectrometry (UPLC/TWIM-TOF-MS) to separate and study different isomeric structures of NAs were investigated. Fifty seven standard compounds belonging to different chemical families of classical NAs were analyzed to obtain their experimental drift times in addition to chromatographic retention time and mass-to-charge information (m / z). These acyclic and cyclic molecules yielded ions with collision cross section (CCS) values ranging from 110 to 210 Å2. The feasibility of the UPLC/TWIM-TOF-MS method to provide a higher degree of confidence in the identification of isomeric structures was evaluated by analyzing the commercial (Sigma-Aldrich) NAs mixture. Identification and structure confirmation of several alicyclic compounds of similar m / z in the NAs mixture were possible by this method. For instance, the presence of previously tentatively identified compounds by the ultrahigh pressure liquid chromatography/quadrupole time of flight mass spectrometry (UPLC/QTOF-MS), such as 4- tert -butylcyclohexanoic acid, 4-dicyclohexylacetic acid or 3,5-dimethyladamantane-1-carboxylic acid, was confirmed. Combining ion mobility separation with UPLC/TOF-MS gives a higher level of selectivity to the overall method by selective interrogation of specific retention time, mass-to-charge and mobility regions. However, there are cases where it is not possible to resolve many similar molecules such as acyclic isomeric compounds in commercial NAs mixture by this technique. This was likely due to the very small CCS area differences among the structural isomeric species. Considerable improvements in the ion mobility resolution and separation will be required for this technique to be able to resolve isomeric species with slight differences in physicochemical properties (e.g., size and structure). [ABSTRACT FROM AUTHOR]

A method for the trace analysis of polar micropollutants (MPs) by direct injection of surface water and groundwater was validated with ultrahigh-performance liquid chromatography using a core-shell biphenyl stationary phase coupled to time-of-flight high-resolution mass spectrometry. The validation was successfully conducted with 33 polar MPs representative for several classes of emerging contaminants. Identification and quantification were achieved by semi-automated processing of full-scan and data-independent acquisition MS/MS spectra. In most cases good linearity (R 2 ≥ 0.99), recovery (75% to 125%) and intra-day (RSD < 20%) and inter-day precision (RSD < 10%) values were observed. Detection limits of 9 to 83 ng/L and 9 to 93 ng/L could be achieved in riverbank filtrate and surface water, respectively. A solid-phase extraction was additionally validated to screen samples from full-scale reverse osmosis drinking water treatment at sub-ng/L levels and overall satisfactory analytical performance parameters were observed for RBF and reverse osmosis permeate. Applicability of the direct injection method is shown for surface water and riverbank filtrate samples from an actual drinking water source. Several targets linkable to incomplete removal in wastewater treatment and farming activities were detected and quantified in concentrations between 28 ng/L for saccharine in riverbank filtrate and up to 1 μg/L for acesulfame in surface water. The solid phase extraction method applied to samples from full-scale reverse osmosis drinking water treatment plant led to quantification of 8 targets between 6 and 57 ng/L in the feed water, whereas only diglyme was detected and quantified in reverse osmosis permeate. Our study shows that combining the chromatographic resolution of biphenyl stationary phase with the performance of time-of-flight high-resolution tandem mass spectrometry resulted in a fast, accurate and robust method to monitor polar MPs in source waters by direct injection with high efficiency. [ABSTRACT FROM AUTHOR]

Low molecular weight heparins (LMWHs), derived from unfractionated heparin (UFH) by chemical or enzymatic degradation, have lower side effects than that of heparin. Enoxaparin, nadroparin, and dalteparin are the most widely used LMWHs. Nadroparin and dalteparin are prepared through nitrous acid degradation followed by a subsequent reduction process, in which specific residue, 2,5-anhydro- d -mannitol (An-Man), is formed at the reducing terminals of generated sugar chains. However, few practicable analytical method was available to analyze An-Man qualitatively and quantitatively. In this work, a HPAEC-PAD-MS method was developed to analyze monosaccharides in heparin and LMWHs, especially An-Man. An ion suppressor is set up between HPAEC and MS to remove the nonvolatile salts from HPAEC and make the elute compatible to MS. Various monosaccharides were separated well with HPAEC. Online MS and MS/MS confirmed all sugar residues in the hydrolysates of heparin samples. The specific residue, An-Man, was only observed in the hydrolysates of LMWHs prepared with nitrous acid degradation and reduction. In addition, major glucosamine and minor arabinose/galactose were observed in all heparin samples. The amounts of these sugar residues were quantitated with PAD, simultaneously. The ratio of glucosamine to An-Man could be used to calculate the molecular weight of LMWHs. The calculated values are comparable to the value measured with size-exclusion chromatography-multiple angle laser scattering detection. Higher the ratio of glucosamine to An-Man higher the molecular weight. The HPAEC-PAD-MS platform is an accurate, precise and efficient way to identify LMWHs by determination of An-Man. It is also an alternative method to detect the MWs of LMWHs having An-Man for quality control purposes. [ABSTRACT FROM AUTHOR]

Efficient targeted identification of chemical constituents from traditional Chinese medicine is still a major challenge. In this study, we used a characteristic ion filtering strategy to characterize compounds of Eucommia ulmoides Oliv. by ultra-high performance liquid chromatography quadrupole time of flight tandem mass spectrometry (UHPLC-ESI-Q-TOF-MS/MS). By using the ion filtering approach, target constituents of Eucommia ulmoides Oliv. were easily tentatively identified from the enormous LC/MS data set. The strategy consisted of the following three steps: 1) To establishing a characteristic ion database by diagnostic product ions or neutral loss fragments; 2) To evaluate the structural information of the compounds by high-resolution diagnostic characteristic ion filtering; 3) To confirm the different classes by chemical profiling according to their MS/MS spectra. In this study, characteristic ions are summarized as five major groups of compounds in Eucommia ulmoides Oliv. In total, 113 compounds were tentatively identified, including 23 potentially novel compounds. The results form a foundation for the quality control and chemical basis of Eucommia ulmoides Oliv. [ABSTRACT FROM AUTHOR]

The performance of seven sub-2-μm particle packed columns (2-picolylamine, 2-PIC; charged surface hybrid fluoro-phenyl, CSH-FP; high strength silica C18 SB, HSS-C 18 ; diethylamine, DEA; 1-aminoanthracene, 1-AA; high density diol and ethylene bridged hybrid; BEH) was examined for lipid separation in ultra-high performance supercritical fluid chromatography (UHPSFC) coupled to quadrupole time-of-flight mass spectrometry. Based on the results of the column screening a method for profiling of multiple lipid species from the major lipid classes was developed. Stationary phases containing β-hydroxy amines, i.e. 1-AA, DEA and 2-PIC, yielded strong retention and poor peak shapes of zwitterionic lipids with primary amine groups, such as phosphatidylserines, phosphatidylethanolamines and its lyso forms. The BEH and HSS-C 18 columns showed strong retention of polar and nonpolar lipids, respectively. The Diol column retained the majority of major lipid classes and also produced symmetric peaks. In addition, this column also produced the highest resolution within and between major lipid classes. An injection solvent composed of methanol:chloroform (1:2, v:v) and the addition of 20 mM ammonium formate in the mobile phase improved chromatographic separation and mass spectrometry detection in comparison to ammonium acetate or absence of additive. Finally, chromatographic and mass spectrometric parameters were optimized for the Diol column using a design of experiments approach. The separation mechanism on the Diol column depended on the lipid functionality and the length and degree of unsaturation of the acyl groups. The developed method could resolve 18 lipid classes and multiple lipids within each class, from blood serum and brain tissue in 11 min. [ABSTRACT FROM AUTHOR]