bims-metlip Biomed News
on Methods and protocols in metabolomics and lipidomics
Issue of 2024‒08‒25
seventeen papers selected by
Sofia Costa, Matterworks
  1. Development and Validation of a Novel Isotope Dilution-Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry Method for Serum C-Peptide.
  2. Structural elucidation of tramadol, its derivatives, and metabolites using chemical derivatization and liquid chromatography-high-resolution tandem mass spectrometry.
  3. Analysis of human biological samples using porous graphitic carbon columns and liquid chromatography-mass spectrometry: a review.
  4. Signal interference between drugs and metabolites in LC-ESI-MS quantitative analysis and its evaluation strategy.
  5. An innovative UPLC-MS/MS method for the quantitation and pharmacokinetics of eupafolin in rat plasma.
  6. Native metabolomics for mass spectrometry-based siderophore discovery.
  7. Pharmacokinetics of two triterpenoid saponins and three flavonoids in Astragalus membranaceus leaves by UHPLC-MS/MS.
  8. Overcoming Challenges in Oligonucleotide Therapeutics Analysis: A Novel Nonion Pair Approach.
  9. Determination of doxorubicin in plasma and tissues of mice by UPLC-MS/MS and its application to pharmacokinetic study.
  10. Substantial benefits of an inert biphenyl column for the analysis of steroids and their phase II metabolites in biological samples.
  11. Addressing stability issues of vildagliptin: Method optimization and validation for accurate analysis in human plasma.
  12. LC-MS metabolomics and lipidomics in cerebrospinal fluid from viral and bacterial CNS infections: a review.
  13. Determination of Choline-Containing Compounds in Rice Bran Fermented with Aspergillus oryzae Using Liquid Chromatography/Tandem Mass Spectrometry.
  14. An end-to-end deep learning method for mass spectrometry data analysis to reveal disease-specific metabolic profiles.
  15. Targeted quantification of per- and polyfluoroalkyl substances (PFASs) in livestock serum by liquid chromatography-high-resolution mass spectrometry.
  16. Analytical methods for the determination of xylazine in pharmaceutical, clinical and forensic matrices - A review.
  17. Crown ether dopant to reduce ion suppression and improve detection in the liquid microjunction surface sampling probe.
  1. Ann Lab Med. 2024 Aug 23.
    Development and Validation of a Novel Isotope Dilution-Ultraperformance Liquid Chromatography-Tandem Mass Spectrometry Method for Serum C-Peptide.
    Sung-Eun Cho, Jungsun Han, Juyoung You, Jun Hyung Lee, Ahram Yi, Sang Gon Lee, Eun Hee Lee.
      Background: Mass spectrometry (MS) methods exhibit higher accuracy and comparability in measuring serum C-peptide concentrations than immunoassays. We developed and validated a novel isotope dilution-ultraperformance liquid chromatography-tandem MS (ID-UPLC-MS/MS) assay to measure serum C-peptide concentrations.Methods: Sample pretreatment involved solid-phase extraction, ion-exchange solid-phase extraction, and derivatization with 6-aminoquinolyl-N-hydroxysuccinimidylcarbamate (Cayman Chemical, Ann Arbor, Michigan, USA). We used an ExionLC UPLC system (Sciex, Framingham, MA, USA) and a Sciex Triple Quad 6500+ MS/MS system (Sciex) for electrospray ionization in positive-ion mode with multiple charge states of [M+3H]3+ and multiple reaction monitoring transitions. The total run time was 50 mins, and the flow rate was 0.20 mL/min. We evaluated the precision, trueness, linearity, lower limit of quantitation (LLOQ), carryover, and matrix effects. Method comparison with electrochemiluminescence immunoassay (ECLIA) was performed in 138 clinical specimens.
    Results: The intra- and inter-run precision coefficients of variation were <5% and the bias values for trueness were <4%, which were all acceptable. The verified linear interval was 0.050-15 ng/mL, and the LLOQ was 0.050 ng/mL. No significant carryover or matrix effects were observed. The correlation between this ID-UPLC-MS/MS method and ECLIA was good (R=0.995, slope=1.564); however, the ECLIA showed a positive bias (51.8%).
    Conclusions: The developed ID-UPLC-MS/MS assay shows acceptable performance in measuring serum C-peptide concentrations. This will be useful in situations requiring accurate measurement of serum C-peptide in clinical laboratories.
    Keywords:  C-peptide; Performance; Tandem mass spectrometry
    DOI:  https://doi.org/10.3343/alm.2024.0072
  2. Rapid Commun Mass Spectrom. 2024 Oct 30. 38(20): e9881
    Structural elucidation of tramadol, its derivatives, and metabolites using chemical derivatization and liquid chromatography-high-resolution tandem mass spectrometry.
    Tamar Shamai Yamin, Avital Shifrovitch, Moran Madmon, Hagit Prihed, Avi Weissberg.
      RATIONALE: Tramadol (T) is a strong painkiller drug that belongs to the opioid analgesic group. Several accidental intoxication cases after oral administration of T have been reported in the past decade. Tramadol, its derivatives, and metabolites present information-limited mass spectra with one prominent peak representing the amine-containing residue; therefore, their structural determination based on both electron impact mass spectrometry (EI-MS) and ESI-MS/MS spectra could be misleading.METHODS: A novel analytical method for the structural elucidation of tramadol, its four homologs, and its two main phase I metabolites (N-desmethyltramadol and O-desmethyltramadol) was developed using chemical modification and liquid chromatography-high-resolution tandem mass spectrometry (LC-HR-MS/MS) with Orbitrap technology.
    RESULTS: After chemical derivatization, each of the investigated T series exhibited informative mass spectra that enabled better exposition of their structures. The developed method was successfully implemented to explicitly identify the structures of tramadol and its N-desmethyltramadol metabolite in urine samples at low ng/mL levels.
    CONCLUSIONS: An efficient derivatization-aided strategy was developed for rapidly elucidating the structure of tramadol-like compounds. The method is intended to assist forensic chemists in better diagnosing T and its analogs and metabolites in clinical or forensic toxicology laboratories.
    DOI:  https://doi.org/10.1002/rcm.9881
  3. Anal Bioanal Chem. 2024 Aug 19.
    Analysis of human biological samples using porous graphitic carbon columns and liquid chromatography-mass spectrometry: a review.
    Taís Betoni Rodrigues, Ricardo Leal Cunha, Paulo Emílio Pereira Barci, Álvaro José Santos-Neto, Fernando Mauro Lanças.
      Liquid chromatography-mass spectrometry (LC-MS) has emerged as a powerful analytical technique for analyzing complex biological samples. Among various chromatographic stationary phases, porous graphitic carbon (PGC) columns have attracted significant attention due to their unique properties-such as the ability to separate both polar and non-polar compounds and their stability through all pH ranges and to high temperatures-besides the compatibility with LC-MS. This review discusses the applicability of PGC for SPE and separation in LC-MS-based analyses of human biological samples, highlighting the diverse applications of PGC-LC-MS in analyzing endogenous metabolites, pharmaceuticals, and biomarkers, such as glycans, proteins, oligosaccharides, sugar phosphates, and nucleotides. Additionally, the fundamental principles underlying PGC column chemistry and its advantages, challenges, and advances in method development are explored. This comprehensive review aims to provide researchers and practitioners with a valuable resource for understanding the capabilities and limitations of PGC columns in LC-MS-based analysis of human biological samples, thereby facilitating advancements in analytical methodologies and biomedical research.
    Keywords:  Bioanalysis; Human biological samples; LC–MS; Polar retention effect on graphite; Porous graphitic carbon columns
    DOI:  https://doi.org/10.1007/s00216-024-05458-8
  4. J Pharm Anal. 2024 Jul;14(7): 100954
    Signal interference between drugs and metabolites in LC-ESI-MS quantitative analysis and its evaluation strategy.
    Fulin Jiang, Jingyu Liu, Yagang Li, Zihan Lu, Qian Liu, Yunhui Xing, Janshon Zhu, Min Huang, Guoping Zhong.
      Liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS) is a widely utilized technique for in vivo pharmaceutical analysis. Ionization interference within electrospray ion source, occurring between drugs and metabolites, can lead to signal variations, potentially compromising quantitative accuracy. Currently, method validation often overlooks this type of signal interference, which may result in systematic errors in quantitative results without matrix-matched calibration. In this study, we conducted an investigation using ten different groups of drugs and their corresponding metabolites across three LC-ESI-MS systems to assess the prevalence of signal interference. Such interferences can potentially cause or enhance nonlinearity in the calibration curves of drugs and metabolites, thereby altering the relationship between analyte response and concentration for quantification. Finally, we established an evaluation scheme through a step-by-step dilution assay and employed three resolution methods: chromatographic separation, dilution, and stable labeled isotope internal standards correction. The above strategies were integrated into the method establishment process to improve quantitative accuracy.
    Keywords:  Drugs; Ionization interference; Liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS); Metabolites; Quantitative analysis
    DOI:  https://doi.org/10.1016/j.jpha.2024.02.008
  5. J Chromatogr B Analyt Technol Biomed Life Sci. 2024 Aug 06. pii: S1570-0232(24)00281-2. [Epub ahead of print]1245 124272
    An innovative UPLC-MS/MS method for the quantitation and pharmacokinetics of eupafolin in rat plasma.
    Mengming Xia, Shunjun Ma, Ying Wang, Dizhong Chen, Lai Jiang, Congcong Wen, Guangliang Wu, Xianqin Wang.
      In this experiment, a rapid and highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technology was established and validated for the quantitation and pharmacokinetic analysis of eupafolin in rat plasma, utilizing licochalcone B as internal standard (IS). After liquid-liquid extraction of the analyte samples by ethyl acetate, chromatographic separation was achieved using a UPLC HSS T3 column under gradient elution conditions, with the mobile phase consisting of acetonitrile and water (with 0.1 % formic acid). Eupafolin was quantified by multiple reaction monitoring (MRM) in electrospray positive-ion mode (ESI+), employing the mass transition m/z 315.2 → 300.3 for eupafolin and m/z 285.4 → 270.3 for IS. Eupafolin demonstrated excellent linear relationship (r > 0.99) over the concentration range of 1.25-1250 ng/mL, with the lower limit of quantification (LLOQ) of the UPLC-MS/MS assay determined as 1.25 ng/mL. Method validation followed the bioanalytical method validation criteria outlined by the FDA. The accuracy of eupafolin ranged from 86.7 % to 111.2 %, and the precision was less than 12 %. The matrix effect was observed at 92.8 %-98.6 %, while the recoveries exceeded 83.2 %. The established UPLC-MS/MS assay was successfully employed for the pharmacokinetic evaluation of eupafolin in rats. The half-lives (t1/2z) were determined to be 1.4 ± 0.4 h and 2.5 ± 1.4 h for intravenous and oral administration, respectively. Notably, the bioavailability of eupafolin was relatively low (8.3 %). The optimized UPLC-MS/MS technology showed highly sensitive, selective, and effective, rendering it suitable for the pharmacokinetics of eupafolin in preclinical practice.
    Keywords:  Bioavailability; Eupafolin; Pharmacokinetics; Rat; UPLC-MS/MS
    DOI:  https://doi.org/10.1016/j.jchromb.2024.124272
  6. Methods Enzymol. 2024 ;pii: S0076-6879(24)00327-6. [Epub ahead of print]702 317-352
    Native metabolomics for mass spectrometry-based siderophore discovery.
    Marquis T Yazzie, Zachary L Reitz, Robin Schmid, Daniel Petras, Allegra T Aron.
      Microorganisms, plants, and animals alike have specialized acquisition pathways for obtaining metals, with microorganisms and plants biosynthesizing and secreting small molecule natural products called siderophores and metallophores with high affinities and specificities for iron or other non-iron metals, respectively. This chapter details a novel approach to discovering metal-binding molecules, including siderophores and metallophores, from complex samples ranging from microbial supernatants to biological tissue to environmental samples. This approach, called Native Metabolomics, is a mass spectrometry method in which pH adjustment and metal infusion post-liquid chromatography are interfaced with ion identity molecular networking (IIMN). This rule-based data analysis workflow that enables the identification of metal-binding species based on defined mass (m/z) offsets with the same chromatographic profiles and retention times. Ion identity molecular networking connects compounds that are structurally similar by their fragmentation pattern and species that are ion adducts of the same compound by chromatographic shape correlations. This approach has previously revealed new insights into metal binding metabolites, including that yersiniabactin can act as a biological zincophore (in addition to its known role as a siderophore), that the recently elucidated lepotchelin natural products are cyanobacterial metallophores, and that antioxidants in traditional medicine bind iron. Native metabolomics can be conducted on any liquid chromatography-mass spectrometry system to explore the binding of any metal or multiple metals simultaneously, underscoring the potential for this method to become an essential strategy for elucidating biological metal-binding molecules.
    Keywords:  Direct infusion; Metallophore discovery; Native mass spectrometry; Native metabolomics; Natural product discovery; Siderophore discovery
    DOI:  https://doi.org/10.1016/bs.mie.2024.07.001
  7. J Pharm Biomed Anal. 2024 Aug 15. pii: S0731-7085(24)00459-X. [Epub ahead of print]251 116419
    Pharmacokinetics of two triterpenoid saponins and three flavonoids in Astragalus membranaceus leaves by UHPLC-MS/MS.
    Ruitong Du, Feng Xu, Deshu Wei, Yuxin Wei, Zhenyue Wang, Zhibin Wang.
      Astragalus membranaceus (A. membranaceus) leaves can be used both as a medicine and food material. Their main chemical components are flavonoids and triterpenoid saponins. The pharmacokinetics of A. membranaceus leaves are rarely reported in the literature. This study aimed to investigate the pharmacokinetics of five major bioactive components of A. membranaceus leaves [rhamnocitrin 3-glucoside (RCG), tiliroside (TIL), rhamnocitrin 3-neohesperidoside (RNH), huangqiyenin R (HuR), and huangqiyenin I (HuI)]. Simultaneously using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method. The extract of A. membranaceus leaves was administered orally to rats, and the rat plasma was subjected to a fast, sensitive, and specific UHPLC-MS/MS method. Butylparaben served as the internal standard. The plasma samples were pretreated using isopropanol/ethyl acetate (1:1, v/v) liquid-liquid extraction. Chromatographic separations were performed at a flow rate of 0.3 mL/min on a Waters ACQUITY HSS T3 Column (2.1 mm × 100 mm, 1.8 μm) using mobile phases of 0.1 % formic acid/water and 0.1 % formic acid/acetonitrile. Mass spectrometry detection was performed using an electrospray ionization ion source in the negative-ion mode and the multiple reaction monitoring mode. All analytes had an intraday and interday relative standard deviation of less than 14.10 %. The range of accuracy was -11.94-6.920 % and -15.22-5.800 %. The lower limits of quantification for RCG, TIL, RNH, HuR, HuI was 10.24, 10.27, 10.12, 5.137, and 5.841 ng/mL, respectively. The criteria were met by stability, matrix effects, and extraction recovery. The pharmacokinetic parameters of A. membranaceus leaf extract were ultimately obtained using this analytical method. The study provides a theoretical basis for future pharmacological research, clinical application, and development of healthy food from A. membranaceus leaves.
    Keywords:  Astragalus membranaceus leaves; Flavonoids; Pharmacokinetics; Rat plasma; Triterpenoid saponins; UHPLC-MS/MS
    DOI:  https://doi.org/10.1016/j.jpba.2024.116419
  8. J Am Soc Mass Spectrom. 2024 Aug 19.
    Overcoming Challenges in Oligonucleotide Therapeutics Analysis: A Novel Nonion Pair Approach.
    Yoshiharu Hayashi, Yuchen Sun.
      Oligonucleotide therapeutics (OT) have emerged as promising drug modality for various intractable diseases. Recently, liquid chromatography-mass spectrometry (LC-MS) has been commonly employed for characterizing and quantifying OT in biological samples. Traditionally, the ion pairing-reverse phase (IP-RP) LC-MS method has been utilized in OT bioanalyses; however, this approach is associated with several limitations, including the memory effect and ion suppression effect of IP reagents. Therefore, this study aimed to develop a new RP-LC-MS method that eliminates the need for IP reagents. Our investigation revealed that ammonium bicarbonate was essential for the successful implementation of this nonIP-RP-LC-MS-based bioanalysis of OT. Moreover, the developed method demonstrated high versatility, accommodating the analysis of various natural or chemically modified oligonucleotides. The sensitivity of the method was further assessed using reconstituted plasma samples (the lower limit of quantification in this experiment was 0.5-1 ng/mL). In summary, the developed nonIP-RP-LC-MS method offers an easy, reliable, and cost-effective approach to the bioanalysis of OT.
    DOI:  https://doi.org/10.1021/jasms.4c00270
  9. Heliyon. 2024 Aug 15. 10(15): e35123
    Determination of doxorubicin in plasma and tissues of mice by UPLC-MS/MS and its application to pharmacokinetic study.
    Zhilin Jin, Xue Xiao, Lili Gui, Qiao Lu, Jicai Zhang.
      A rapid and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for the simultaneous determination of doxorubicin (DOX) in mouse plasma and tissues, including the heart, liver, spleen, lung, kidney and tumor, and to investigate the pharmacokinetics and distribution in mice. In this study, daunorubicin (DNR) was used as an internal standard, and the mobile phase consisted of ammonium formate 2 mM containing 0.1 % formic acid (A) and acetonitrile (B), the chromatographic column was ACQUITY UPLC BEHTM C18 with a gradient elution at a flow rate of 0.2 mL/min. Electrospray ionization (ESI) in positive ion pattern was utilized for the ion separation of DOX, with the ions used for quantitative analysis being DOX m/z 544.28 → 397.10 and DNR m/z 528.35 → 321.08, respectively. The results showed that a good linear relationship in the calibration curve range of 1-800 ng/mL in mouse plasma and 1-2500 ng/g in tissues (R2 > 0.99) with the limits of quantification of 1 ng/mL in plasma and tissues. The method exhibited good matrix effect and extraction recovery, with the intra-day and inter-day precision of plasma and tissue were less than 10.3 % and 15.4 %, and the relative error (RE) were both less than ±14.8 % and ±18.9 %, respectively. The stability results under different conditions were found to be accurate. It also revealed the distribution of DOX in various tissues of mice, with the concentration ranking as liver > heart > kidney > spleen > lung > tumor. This method was successfully used to the study for the pharmacokinetics in plasma and drug distribution in tissues of BALB/c mice.
    Keywords:  Doxorubicin; Drug distribution; Pharmacokinetics; UPLC-MS/MS
    DOI:  https://doi.org/10.1016/j.heliyon.2024.e35123
  10. J Sep Sci. 2024 Aug;47(16): e2400436
    Substantial benefits of an inert biphenyl column for the analysis of steroids and their phase II metabolites in biological samples.
    Mathieu Galmiche, Marie-Anaïs Monat, Diego A Lopez, Cyrille Lamboley, Paul Connolly, Sergey Girel, Davy Guillarme, Isabel Meister, Serge Rudaz.
      Steroids can be used as biomarkers in clinical metabolomics and other fields related to human toxicology. This chemical group is known for its complexity, considering its number of isobaric compounds and the wide variety of phases I and II metabolic pathways that parent compounds can undergo. For a successful analysis of steroids in biological samples, liquid chromatography separation must be finely tuned. It is especially challenging for glucuronidated and sulfated steroids derivatives that bear polar heads and can be affected by non-specific adsorption. The benefits of a biphenyl stationary phase chemistry for the selectivity of the separation of steroids and their phase II metabolites and the extent to which nonspecific adsorption phenomena could degrade chromatographic performance were investigated. Replacing a conventional hardware by a passivated hardware allowed to considerably reduce peaks width and asymmetry of sulfated species. The addition of weak ion pairing agents in the mobile phase could also help to reduce non-specific adsorption but are detrimental to mass spectrometry detection. As confirmed by the successful detection of 52 steroids in plasma, the use of a biphenyl stationary phase complemented by a passivated column hardware is of great help for a successful biomedical analysis of steroids and their phase II metabolites.
    Keywords:  glucuronides; liquid chromatography; non‐specific adsorption; steroids; sulfates
    DOI:  https://doi.org/10.1002/jssc.202400436
  11. Biomed Chromatogr. 2024 Aug 20. e5991
    Addressing stability issues of vildagliptin: Method optimization and validation for accurate analysis in human plasma.
    Santosh Tawari, Ujashkumar Shah.
      This research paper introduces novel strategies to address the stability issues arising with vildagliptin, marking the first attempt to tackle this challenge comprehensively. The study incorporates malic acid into the human plasma, a crucial step in stabilizing vildagliptin and preventing its degradation. Additionally, optimization of the elution process on a C18 Asentis Express column, fine-tuned with a combination of acetonitrile and ammonium trifluoroacetate 5mM, ensures optimal chromatographic conditions. For detection and quantification, electrospray ionization (ESI) is employed, monitoring multiple reactions for vildagliptin (304.2 → 154.2) and vildagliptin D7 (311.1 → 161.2). Meticulous validation of the method demonstrates high accuracy (97.30%-104.15%) and precision [(0.32%-3.09% coefficient of variance (CV)] for vildagliptin calibration curve standards (CC STD), establishing its sensitivity and reliability in measuring vildagliptin levels. This refined methodology offers numerous advantages, including the elimination of stability concerns, reduced human plasma sample volume (100 μL), exceptional reproducibility, shortened run time (~2.2 min), and a wide concentration range (1.00 to 851.81 ng/mL). These attributes make it exceptionally well-suited for diverse research applications, spanning from extensive sampling in therapeutic drug monitoring units to bioequivalence and bioavailability studies, as well as pharmacokinetic investigations of vildagliptin.
    Keywords:  K2EDTA human plasma; LC–MS/MS; bioanalytical method; malic acid; vildagliptin
    DOI:  https://doi.org/10.1002/bmc.5991
  12. Front Neurol. 2024 ;15 1403312
    LC-MS metabolomics and lipidomics in cerebrospinal fluid from viral and bacterial CNS infections: a review.
    Ontefetse Neo Plaatjie, A Marceline Tutu van Furth, Martijn van der Kuip, Shayne Mason.
      There is compelling evidence that a dysregulated immune inflammatory response in neuroinfectious diseases results in modifications in metabolic processes and altered metabolites, directly or indirectly influencing lipid metabolism within the central nervous system (CNS). The challenges in differential diagnosis and the provision of effective treatment in many neuroinfectious diseases are, in part, due to limited understanding of the pathophysiology underlying the disease. Although there are numerous metabolomics studies, there remains a deficit in neurolipidomics research to provide a comprehensive understanding of the connection between altered metabolites and changes in lipid metabolism. The brain is an inherently high-lipid organ; hence, understanding neurolipidomics is the key to future breakthroughs. This review aims to provide an integrative summary of altered cerebrospinal fluid (CSF) metabolites associated with neurolipid metabolism in bacterial and viral CNS infections, with a particular focus on studies that used liquid chromatography-mass spectrometry (LC-MS). Lipid components (phospholipids) and metabolites (carnitine and tryptophan) appear to be the most significant indicators in both bacterial and viral infections. On the basis of our analysis of the literature, we recommend employing neurolipidomics in conjunction with existing neurometabolomics data as a prospective method to enhance our understanding of the cross link between dysregulated metabolites and lipid metabolism in neuroinfectious diseases.
    Keywords:  central nervous system; cerebrospinal fluid; encephalitis; lipidomics; liquid chromatography mass spectrometer; meningitis; metabolomics; neuroinflammation
    DOI:  https://doi.org/10.3389/fneur.2024.1403312
  13. Mass Spectrom (Tokyo). 2024 ;13(1): A0151
    Determination of Choline-Containing Compounds in Rice Bran Fermented with Aspergillus oryzae Using Liquid Chromatography/Tandem Mass Spectrometry.
    Masamitsu Maekawa, Anna Iwahori, Masaki Kumondai, Yu Sato, Toshihiro Sato, Nariyasu Mano.
      Choline-containing compounds are essential nutrients for human activity, as they are involved in many biological processes, including cell membrane organization, methyl group donation, neurotransmission, signal transduction, lipid transport, and metabolism. These compounds are normally obtained from food. Fermented brown rice and rice bran with Aspergillus oryzae (FBRA) is a fermented food product derived from rice and rice ingredients. FBRA exhibits a multitude of functional properties with respect to the health sciences. This study has a particular focus on choline-containing compounds. We first developed a simultaneous liquid chromatography/tandem mass spectrometry (LC/MS/MS) analysis method for seven choline-containing compounds. The method was subsequently applied to FBRA and its ingredients. Hydrophilic interaction chromatography (HILIC) and selected reaction monitoring were employed for the simultaneous analysis of seven choline-containing compounds. MS ion source conditions were optimized in positive ion mode, and the product ions derived from the choline group were obtained through MS/MS optimization. Under optimized HILIC conditions, the peaks exhibited good shape without peak tailing. Calibration curves demonstrated high linearity across a 300- to 10,000-fold concentration range. The application of the method to FBRA and other ingredients revealed significant differences between food with and without fermentation. In particular, betaine and α-glycerophosphocholine were found to be highest in FBRA and brown rice malt, respectively. The results indicated that the fermentation processing of rice ingredients results in alterations to the choline-containing compounds present in foods. The developed HILIC/MS/MS method proved to be a valuable tool for elucidating the composition of choline-containing compounds in foods.
    Keywords:  HILIC/MS/MS; choline-containing compounds; fermented brown rice and rice bran with Aspergillus oryzae; simultaneous analysis
    DOI:  https://doi.org/10.5702/massspectrometry.A0151
  14. Nat Commun. 2024 Aug 20. 15(1): 7136
    An end-to-end deep learning method for mass spectrometry data analysis to reveal disease-specific metabolic profiles.
    Yongjie Deng, Yao Yao, Yanni Wang, Tiantian Yu, Wenhao Cai, Dingli Zhou, Feng Yin, Wanli Liu, Yuying Liu, Chuanbo Xie, Jian Guan, Yumin Hu, Peng Huang, Weizhong Li.
      Untargeted metabolomic analysis using mass spectrometry provides comprehensive metabolic profiling, but its medical application faces challenges of complex data processing, high inter-batch variability, and unidentified metabolites. Here, we present DeepMSProfiler, an explainable deep-learning-based method, enabling end-to-end analysis on raw metabolic signals with output of high accuracy and reliability. Using cross-hospital 859 human serum samples from lung adenocarcinoma, benign lung nodules, and healthy individuals, DeepMSProfiler successfully differentiates the metabolomic profiles of different groups (AUC 0.99) and detects early-stage lung adenocarcinoma (accuracy 0.961). Model flow and ablation experiments demonstrate that DeepMSProfiler overcomes inter-hospital variability and effects of unknown metabolites signals. Our ensemble strategy removes background-category phenomena in multi-classification deep-learning models, and the novel interpretability enables direct access to disease-related metabolite-protein networks. Further applying to lipid metabolomic data unveils correlations of important metabolites and proteins. Overall, DeepMSProfiler offers a straightforward and reliable method for disease diagnosis and mechanism discovery, enhancing its broad applicability.
    DOI:  https://doi.org/10.1038/s41467-024-51433-3
  15. J Vet Diagn Invest. 2024 Aug 17. 10406387241268224
    Targeted quantification of per- and polyfluoroalkyl substances (PFASs) in livestock serum by liquid chromatography-high-resolution mass spectrometry.
    Xin Xu, Lisa A Murphy.
      Per- and polyfluoroalkyl substances (PFASs) have attracted increasing attention due to their persistence in the environment and potential adverse effects on human and animal health. The detection and quantification of PFASs in livestock could substantially contribute to monitoring their presence within the food chain. We developed a targeted quantification method for 34 PFASs in livestock serum by liquid chromatography-high-resolution mass spectrometry (LC-HRMS). We used protein precipitation for serum sample extraction and accurate mass measurement of targeted PFAS compounds for quantification. We validated the method with various analytical parameters, achieving accuracy of 70-120% and precision of <20%. The method also demonstrated good analytical sensitivity, with a limit of detection of <0.051 ng/mL and a limit of quantification of <0.175 ng/mL. When applying the developed method to actual serum samples from a variety of livestock, we successfully identified and quantified various PFASs in different livestock species. Our method has the potential to be a valuable tool for veterinary laboratory analysis of PFAS contamination in livestock.
    Keywords:  PFAS; liquid chromatography–high-resolution mass spectrometry; livestock; serum
    DOI:  https://doi.org/10.1177/10406387241268224
  16. Med Sci Law. 2024 Aug 23. 258024241275899
    Analytical methods for the determination of xylazine in pharmaceutical, clinical and forensic matrices - A review.
    Sachil Kumar, Hemi Gayakwad, Tulsidas R Baggi.
      Xylazine, a non-opioid veterinary anaesthetic tranquillizer that is not licensed for human use, has been linked to an increase in overdose fatalities worldwide. The study delves into the forensic aspects of xylazine usage, emphasizing on chemical, clinical and toxicological analyses of drug seizures, bodily fluids and tissues. It advocates for validated analytical methods for determining xylazine. This study provides supporting material to pave the path for the usage and development of relevant and verified alternative screening and confirmation methods for laboratories. Google Scholar, Scopus, Science Direct and PubMed were searched for relevant articles and case reports in relation to xylazine misuse and established analytical methods for forensic investigation until April 2023. A total of 79 articles were evaluated, and 40 publications met the inclusion criteria. The most prevalent xylazine exposures recorded were incidental and intentional misuse/abuse. Common symptoms upon presentation were hypotension, bradycardia, drowsiness and lethargy, although mortality was less prevalent. Solid-phase extraction and liquid-liquid extraction are two extensively used sample preparation techniques. These techniques are used to extract desired analytes from complex matrices. Several analytical techniques have been stated, including GC-MS, LC-MS/MS, HPLC-DAD and others. The analytical procedures used are determined by the matrices involved, the amount of xylazine present, interfering compounds, the degree of precision required and the laboratory infrastructure. In the present context, the LC-MS/MS methods are preferred as the gold standard. In the near future, many analytical techniques such as capillary electrophoresis, PSI-MS, immuno-analytical techniques and SERRS may show significant potential.
    Keywords:  Xylazine; analytical methods; drug of abuse; human; veterinary anesthetic; veterinary tranquillizer
    DOI:  https://doi.org/10.1177/00258024241275899
  17. Rapid Commun Mass Spectrom. 2024 Oct 30. 38(20): e9889
    Crown ether dopant to reduce ion suppression and improve detection in the liquid microjunction surface sampling probe.
    Haidy Metwally, Jian Yu, Rachel Theriault, Jennifer L Kolwich, Randy Ellis, Avena C Ross, Richard D Oleschuk.
      RATIONALE: Sodium and potassium are required in agar media for the growth of some microorganisms (e.g., marine bacteria). However, alkali cations are a significant source of contamination for mass spectrometry causing ion suppression and adduct formation. Conventionally, salts can be removed before mass spectrometric analysis with appropriate and often lengthy sample preparation. The direct mass spectrometric sampling of bacterial colonies grown on agar media seeks to minimize or eliminate sample preparation to improve workflow. However, this may exacerbate ion suppression and contamination since these metal cations will degrade spectral quality and limit the rapid profiling of microbial metabolites. Different approaches are needed to sequester sodium and potassium ions to minimize unwanted background interferences. Herein, we use crown ethers (CEs) in combination with a liquid microjunction surface sampling probe (LMJ-SSP) to directly sample the surface of the bacterial colonies from two marine bacteria species (Pseudoalteromonas rubra DSM6842 and Pseudoalteromonas tunicata DSM 14096). CEs (e.g., 18-crown-6 or 15-crown-5) are added to the carrier solvent of the LMJ-SSP, the chemical noise is reduced, and spectra are easier to interpret.METHODS: The liquid microjunction formed at the tip of LMJ-SSP was used to directly touch bacterial colonies on agar. The carrier solvent was either methanol (100%) or methanol: H2O (50:49.9%) with or without 0.01% CEs. Information-theoretic measures are employed to investigate qualitative changes between spectra before and after adding CEs.
    RESULTS: Our work demonstrates the capability of CEs to reduce background interferences within the direct profiling of bacterial colonies from agar plates. The data obtained from both P. rubra DSM6842 and P. tunicata DSM 14096 show that CEs can be used to mitigate the salty background and improve compound detection.
    CONCLUSION: Our approach can be implemented in natural product discovery using LMJ-SSP to allow fast and accurate detection of interesting/novel compounds.
    DOI:  https://doi.org/10.1002/rcm.9889
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