bims-metlip Biomed News
on Methods and protocols in metabolomics and lipidomics
Issue of 2024‒04‒21
eighteen papers selected by
Sofia Costa, Matterworks
  1. Applications of chromatographic methods in metabolomics: A review.
  2. LipiDex 2 Integrates MSn Tree-Based Fragmentation Methods and Quality Control Modules to Improve Discovery Lipidomics.
  3. Interplatform comparison between three ion mobility techniques for human plasma lipid collision cross sections.
  4. Improved lipid analysis using a 2D-LC-MS system with a novel injection procedure.
  5. Extended similarity methods for efficient data mining in imaging mass spectrometry.
  6. Chiral analysis of amphetamine, methamphetamine, MDMA and MDA enantiomers in human hair samples.
  7. Chemoselectivity Strategy Based on B-Label Integrated with Tailored COF for Targeted Metabolomic Analysis of Short-Chain Fatty Acids by UHPLC-MS/MS.
  8. Ion Mobility Mass Spectrometry-based Disaccharide Analysis of Glycosaminoglycans.
  9. A dilute and shoot method for urinary free cortisol analysis by LC-MS/MS.
  10. Quantification of the aromatase inhibitor letrozole and its carbinol metabolite in mouse plasma by UHPLC-MS/MS.
  11. A comprehensive HRMS methodology using LC-(ESI)-/GC-(APCI)-QTOF MS complementary platforms for wide-scope target screening of >750 pesticides in olive oil.
  12. Simultaneous quantification and confirmation of oxycodone and its metabolites in equine urine using ultra-high performance liquid chromatography-tandem mass spectrometry.
  13. Derivatization-free determination of chiral plasma pharmacokinetics of MDMA and its enantiomers.
  14. Chemical derivatization strategies for enhancing the HPLC analytical performance of natural active triterpenoids.
  15. How Much Storage Precision Can Be Lost: Guidance for Near-Lossless Compression of Untargeted Metabolomics Mass Spectrometry Data.
  16. Phytosterols in human serum as measured using a liquid chromatography tandem mass spectrometry.
  17. Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry by Matrix-Assisted Laser Desorption Ionization.
  18. Analytical Methods for Brassinosteroid Analysis: Recent Advances and Applications.
  1. J Chromatogr B Analyt Technol Biomed Life Sci. 2024 Apr 16. pii: S1570-0232(24)00132-6. [Epub ahead of print]1239 124124
    Applications of chromatographic methods in metabolomics: A review.
    Susan T Ovbude, Sadia Sharmeen, Isaac Kyei, Harshana Olupathage, Jacob Jones, Richard J Bell, Robert Powers, David S Hage.
      Chromatography is a robust and reliable separation method that can use various stationary phases to separate complex mixtures commonly seen in metabolomics. This review examines the types of chromatography and stationary phases that have been used in targeted or untargeted metabolomics with methods such as mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. General considerations for sample pretreatment and separations in metabolomics are considered, along with the various supports and separation formats for chromatography that have been used in such work. The types of liquid chromatography (LC) that have been most extensively used in metabolomics will be examined, such as reversed-phase liquid chromatography and hydrophilic liquid interaction chromatography. In addition, other forms of LC that have been used in more limited applications for metabolomics (e.g., ion-exchange, size-exclusion, and affinity methods) will be discussed to illustrate how these techniques may be utilized for new and future research in this field. Multidimensional LC methods are also discussed, as well as the use of gas chromatography and supercritical fluid chromatography in metabolomics. In addition, the roles of chromatography in NMR- vs. MS-based metabolomics are considered. Applications are given within the field of metabolomics for each type of chromatography, along with potential advantages or limitations of these separation methods.
    Keywords:  Gas chromatography; Liquid chromatography; Mass spectrometry; Metabolomics; Nuclear magnetic resonance spectroscopy; Supercritical fluid chromatography
    DOI:  https://doi.org/10.1016/j.jchromb.2024.124124
  2. Anal Chem. 2024 Apr 19.
    LipiDex 2 Integrates MSn Tree-Based Fragmentation Methods and Quality Control Modules to Improve Discovery Lipidomics.
    Benton J Anderson, Dain R Brademan, Yuchen He, Katherine A Overmyer, Joshua J Coon.
      As lipidomics experiments increase in scale and complexity, data processing tools must support workflows for new liquid chromatography-mass spectrometry (LC-MS) methods while simultaneously supporting quality controls to maximize the confidence in lipid identifications. LipiDex 2 improves lipidomics data processing algorithms from LipiDex 1 and introduces new tools for spectral matching and peak annotation functions, with improvements in speed and user-friendliness. In silico spectral library generation now supports tandem mass spectral (MSn) tree-based fragmentation methods, and the LipiDex 2 workflow fully integrates the fragmentation logic into the data processing steps to enable lipid identification at the appropriate level of structural resolution. Finally, LipiDex 2 features new modules for automated quality control checks that also allow users to visualize data quality in a data dashboard user interface.
    DOI:  https://doi.org/10.1021/acs.analchem.4c00359
  3. Anal Chim Acta. 2024 May 22. pii: S0003-2670(24)00336-2. [Epub ahead of print]1304 342535
    Interplatform comparison between three ion mobility techniques for human plasma lipid collision cross sections.
    Anaïs C George, Isabelle Schmitz, Florent Rouvière, Sandra Alves, Benoit Colsch, Sabine Heinisch, Carlos Afonso, François Fenaille, Corinne Loutelier-Bourhis.
      The implementation of ion mobility spectrometry (IMS) in liquid chromatography-high-resolution mass spectrometry (LC-HRMS) workflows has become a valuable tool for improving compound annotation in metabolomics analyses by increasing peak capacity and by adding a new molecular descriptor, the collision cross section (CCS). Although some studies reported high repeatability and reproducibility of CCS determination and only few studies reported good interplatform agreement for small molecules, standardized protocols are still missing due to the lack of reference CCS values and reference materials. We present a comparison of CCS values of approximatively one hundred lipid species either commercially available or extracted from human plasma. We used three different commercial ion mobility technologies from different laboratories, drift tube IMS (DTIMS), travelling wave IMS (TWIMS) and trapped IMS (TIMS), to evaluate both instrument repeatability and interlaboratory reproducibility. We showed that CCS discrepancies of 0.3% (average) could occur depending on the data processing software tools. Moreover, eleven CCS calibrants were evaluated yielding mean RSD below 2% for eight calibrants, ESI Low concentration tuning mix (Tune Mix) showing the lowest RSD (< 0.5%) in both ion modes. Tune Mix calibrated CCS from the three different IMS instruments proved to be well correlated and highly reproducible (R2 > 0.995 and mean RSD ≤ 1%). More than 90% of the lipid CCS had deviations of less than 1%, demonstrating high comparability between techniques, and the possibility to use the CCS as molecular descriptor. We highlighted the need of standardized procedures for calibration, data acquisition, and data processing. This work demonstrates that using harmonized analytical conditions are required for interplatform reproducibility for CCS determination of human plasma lipids.
    Keywords:  Collision cross section; Drift tube ion mobility spectrometry; Inter-laboratory comparison; Lipidomics; Trapped ion mobility spectrometry; Travelling wave ion mobility spectrometry
    DOI:  https://doi.org/10.1016/j.aca.2024.342535
  4. J Chromatogr B Analyt Technol Biomed Life Sci. 2024 Apr 15. pii: S1570-0232(24)00137-5. [Epub ahead of print]1239 124129
    Improved lipid analysis using a 2D-LC-MS system with a novel injection procedure.
    József Pánczél, Vilmos Kertesz, Matthias Schiell.
      The aim of this study was to improve analysis of nonpolar lipidomics sample extracts using reversed phase (RP) chromatography. A 4/3/3 (v/v/v) mixture of methanol/methyl tert-butyl ether/chloroform (MeOH/MTBE/CHCl3, MMC) was chosen for sample extraction solvent based on its proven extraction capability for several lipid classes. To avoid carry over, loss of analytes and peak distortion the loops and all capillaries of the presented LC system were flushed and filled up with methanol until the analytical column. The choice of methanol was due to its weak elution strength and being infinitely miscible with MMC and several other nonpolar solvents. This allowed injection of a 100 μl sample that was 20 μl nonpolar extraction solvent diluted fivefold with methanol. All lipids of 25 lipid classes were transferred quantitatively to the column head where the online dilution of methanol was carried out with aqueous eluent for focusing the lipid analytes. The weak elution strength of methanol prevented peak distortions. The consecutive reversed phase elution resulted in remarkably narrow peaks (full width at half maximum was 0.07-0.08 min typically) and enhanced sensitivity (limit of detection usually in sub nM region) because of increased sample injection volume and narrow peaks. Calibration and quality control samples made by diluting commercial lipid standards 200-50000 times confirmed the applicability of this approach both for targeted lipid quantification and for untargeted quantitative comparison of lipids from different sources.
    Keywords:  Lipidomics; Mass spectrometry; Reversed phase (RP) chromatography; Signal enhancement
    DOI:  https://doi.org/10.1016/j.jchromb.2024.124129
  5. Digit Discov. 2024 Apr 17. 3(4): 805-817
    Extended similarity methods for efficient data mining in imaging mass spectrometry.
    Nicholas R Ellin, Yingchan Guo, Ramón Alain Miranda-Quintana, Boone M Prentice.
      Imaging mass spectrometry is a label-free imaging modality that allows for the spatial mapping of many compounds directly in tissues. In an imaging mass spectrometry experiment, a raster of the tissue surface produces a mass spectrum at each sampled x, y position, resulting in thousands of individual mass spectra, each comprising a pixel in the resulting ion images. However, efficient analysis of imaging mass spectrometry datasets can be challenging due to the hyperspectral characteristics of the data. Each spectrum contains several thousand unique compounds at discrete m/z values that result in unique ion images, which demands robust and efficient algorithms for searching, statistical analysis, and visualization. Some traditional post-processing techniques are fundamentally ill-equipped to dissect these types of data. For example, while principal component analysis (PCA) has long served as a useful tool for mining imaging mass spectrometry datasets to identify correlated analytes and biological regions of interest, the interpretation of the PCA scores and loadings can be non-trivial. The loadings often contain negative peaks in the PCA-derived pseudo-spectra, which are difficult to ascribe to underlying tissue biology. Herein, we have utilized extended similarity indices to streamline the interpretation of imaging mass spectrometry data. This novel workflow uses PCA as a pixel-selection method to parse out the most and least correlated pixels, which are then compared using the extended similarity indices. The extended similarity indices complement PCA by removing all non-physical artifacts and streamlining the interpretation of large volumes of imaging mass spectrometry spectra simultaneously. The linear complexity, O(N), of these indices suggests that large imaging mass spectrometry datasets can be analyzed in a 1 : 1 scale of time and space with respect to the size of the input data. The extended similarity indices algorithmic workflow is exemplified here by identifying discrete biological regions of mouse brain tissue.
    DOI:  https://doi.org/10.1039/d3dd00165b
  6. J Anal Toxicol. 2024 Mar 29. pii: bkae026. [Epub ahead of print]
    Chiral analysis of amphetamine, methamphetamine, MDMA and MDA enantiomers in human hair samples.
    Julian Bickel, Anne Szewczyk, Nadine Aboutara, Hilke Jungen, Alexander Müller, Benjamin Ondruschka, Stefanie Iwersen-Bergmann.
      A novel analytical method was developed for the simultaneous quantification of the R/S-enantiomers of amphetamine, methamphetamine, MDA and MDMA in hair samples using liquid chromatography-tandem mass spectrometry (LC-MS-MS). This method involved a straightforward derivatization step with dansyl chloride and the use of a chiral column, enabling the separation and quantification of all eight enantiomers in a single analysis. The method exhibited excellent linearity across a concentration range of 0.03-3.00 ng/mg for each enantiomer. Precision and accuracy were within acceptable limits, with bias and relative standard deviation (RSD) values consistently below 6% and 9%, respectively. Selectivity and specificity assessments confirmed the absence of any interference from contaminants or co-extracted drugs. The method demonstrated high sensitivity, with limits of detection (LOD) below 8 pg/mg and limits of quantification (LOQ) below 19 pg/mg for all analytes. Extraction recovery exceeded 79%, and matrix effects were minimal for all analytes. Processed sample stability evaluations revealed consistent results with deviations below 11% for all analytes. Application of the method to 32 authentic human hair samples provided valuable insights into amphetamine use patterns, allowing differentiation between medical amphetamine consumption and illicit use based on enantiomeric composition. Additionally, the method detected co-use of methamphetamine, MDA or MDMA in some samples, highlighting its applicability in drug monitoring and real-life case scenarios within a forensic institute. This innovative analytical approach offers a sensitive and selective method for enantiomeric differentiation of amphetamine, methamphetamine, MDA and MDMA in human hair samples, providing a valuable tool for forensic and clinical investigations.
    DOI:  https://doi.org/10.1093/jat/bkae026
  7. Anal Chem. 2024 Apr 18.
    Chemoselectivity Strategy Based on B-Label Integrated with Tailored COF for Targeted Metabolomic Analysis of Short-Chain Fatty Acids by UHPLC-MS/MS.
    Yue Yuan, Mengxin Ren, Chengze Zhu, Yanwei Lou, Qinghua Liang, Zhili Xiong.
      Chemoselective extraction strategy is an emerging and powerful means for targeted metabolomics analysis, which allows for the selective identification of biomarkers. Short-chain fatty acids (SCFAs) as functional metabolites for many diseases pose challenges in qualitative and quantitative analyses due to their high polarity and uneven abundance. In our study, we proposed the B-labeled method for the derivatization of SCFAs using easily available 3-aminobenzeneboronic acid as the derivatization reagent, which enables the introduction of recognition unit (boric acid groups). To analyze the B-labeled targeted metabolites accurately, cis-diol-based covalent organic framework (COF) was designed to specifically capture and release target compounds by pH-response borate affinity principle. The COF synthesized by the one-step Schiff base reaction possessed a large surface area (215.77 m2/g), excellent adsorption capacity (774.9 μmol/g), good selectivity, and strong regeneration ability (20 times). Combined with ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis, our results indicated that the detection sensitivities of SCFAs increased by 1.2-2500 folds compared with unlabeled method, and the retention time and isomer separation were improved. Using this strategy, we determined twenty-six SCFAs in the serum and urine of rats in four groups about osteoporosis and identified important biomarkers related to the tricarboxylic acid cycle and fatty acid metabolism pathways. In summary, UHPLC-MS/MS based on B-labeled derivatization with tailored COF strategy shows its high selectivity, excellent sensitivity, and good chromatographic behavior and has remarkable application prospect in targeted metabolomics study of biospecimens.
    DOI:  https://doi.org/10.1021/acs.analchem.3c05590
  8. Chemistry. 2024 Apr 17. e202400783
    Ion Mobility Mass Spectrometry-based Disaccharide Analysis of Glycosaminoglycans.
    Lukasz Polewski, Eunjin Moon, Andreas Zappe, Michael Götze, Gergő Péter Szekeres, Christian Roth, Kevin Pagel.
      Glycosaminoglycans (GAGs) are linear and acidic polysaccharides. They are ubiquitous molecules, which are involved in a wide range of biological processes. Despite being structurally simple at first glance, with a repeating backbone of alternating hexuronic acid and hexosamine dimers, GAGs display a highly complex structure, which predominantly results from their heterogeneous sulfation patterns. The commonly applied method for compositional analysis of all GAGs is "disaccharide analysis." In this process, GAGs are enzymatically depolymerized into disaccharides, derivatized with a fluorescent label, and then analysed through liquid chromatography. The limiting factor in the high throughput analysis of GAG disaccharides is the time-consuming liquid chromatography. To address this limitation, we here utilized trapped ion mobility-mass spectrometry (TIM-MS) for the separation of isomeric GAG disaccharides, which reduces the measurement time from hours to a few minutes. A full set of disaccharides comprises twelve structures, with eight possessing isomers. Most disaccharides cannot be differentiated by TIM-MS in underivatized form. Therefore, we developed chemical modifications to reduce sample complexity and enhance differentiability. Quantification is performed using stable isotope labelled standards, which are easily available due to the nature of the performed modifications.
    Keywords:  disaccharide analysis; glycosaminoglycans; heparin; quantification; trapped ion mobility spectrometry
    DOI:  https://doi.org/10.1002/chem.202400783
  9. J Chromatogr B Analyt Technol Biomed Life Sci. 2024 Apr 15. pii: S1570-0232(24)00135-1. [Epub ahead of print]1239 124127
    A dilute and shoot method for urinary free cortisol analysis by LC-MS/MS.
    Ying Shen, Xia Luo, Qing Guan, Liming Cheng.
      24-hour urinary free cortisol (UFC) is considered as the first-line test for screening and diagnosis of Cushing's syndrome. Although 24-hour UFC assay has been extensively studied by liquid chromatography-tandem mass spectrometry (LC-MS/MS), an accurate assay coupled with a reliable sample preparation procedure and a method-specific reference interval would be very important for reasonable diagnosis. In this study, a simple dilute and shoot method has been proposed for UFC determination by LC-MS/MS. Namely, 50 µL of urine sample was mixed with 200 µL of a 50 % methanol/water solution containing the internal standard cortisol-13C3. The mixture was centrifuged and the supernatant was used for direct analysis by LC-MS/MS. This method was validated with wide linear range from 0.625 to 500 ng/ml with coefficients of variation (CVs) ≤ 3.64 %, excellent precision (intra-day CVs ≤ 5.70 % and inter-day CVs ≤ 5.33 %) and good recovery in the range of 93.3-109 %. The preservatives were further evaluated for urine storage. It was recommended that no preservatives could be used in collection of 24-hour urine for good detecting peaks. The investigation of reference interval and diagnostic performance finally confirmed the potential usage of this LC-MS/MS assay in routing clinical testing.
    Keywords:  24-hour urine; Cortisol; Cushing’s syndrome; LC-MS/MS; Preservative
    DOI:  https://doi.org/10.1016/j.jchromb.2024.124127
  10. J Chromatogr B Analyt Technol Biomed Life Sci. 2024 Apr 02. pii: S1570-0232(24)00114-4. [Epub ahead of print]1238 124106
    Quantification of the aromatase inhibitor letrozole and its carbinol metabolite in mouse plasma by UHPLC-MS/MS.
    Hanieh Taheri, Yan Jin, Eman Ahmed, Peng Hu, Yang Li, Alex Sparreboom, Shuiying Hu.
      A liquid chromatography - electrospray ionization-mass spectrometry (LC-ESI-MS) method was developed for the quantification of letrozole, a third-generation aromatase inhibitor, and its main carbinol metabolite (CM) in support of murine pharmacokinetic studies. Using polarity switching, simultaneous ESI-MS measurement of letrozole and CM was achieved in positive and negative mode, respectively. The assay procedure involved a one-step protein precipitation and extraction of all analytes from mouse plasma requiring only 5 μL of sample. Separation was optimized on an Accucore aQ column with gradient elution at a flow rate of 0.4 mL/min in 5 min. Two calibration curves per day over four consecutive measurement days showed satisfactory linear responses (r2 > 0.99) over concentration ranges of 5-1000 ng/mL and 20-2000 ng/mL for letrozole and CM, respectively. No matrix effect was found, and the mean extraction recoveries were 103-108 % for letrozole and 99.8-107 % for CM. Precision and accuracy within a single run and over four consecutive measurement days were verified to be within acceptable limits. Application of the developed method to preclinical pharmacokinetic studies in mice receiving oral letrozole at a dose 1 or 10 mg/kg revealed that the systemic exposure to letrozole was dose-, formulation-, and strain-dependent. These findings may inform the future design of preclinical studies aimed at refining the pharmacological profile of this clinically important drug.
    Keywords:  Aromatase inhibitors; Letrozole; Mouse plasma; Pharmacokinetics; UHPLC-MS/MS
    DOI:  https://doi.org/10.1016/j.jchromb.2024.124106
  11. Anal Methods. 2024 Apr 16.
    A comprehensive HRMS methodology using LC-(ESI)-/GC-(APCI)-QTOF MS complementary platforms for wide-scope target screening of >750 pesticides in olive oil.
    Sofia K Drakopoulou, Stefanos E Kokolakis, Apostolos L Karagiannidis, Marilena E Dasenaki, Niki C Maragou, Nikolaos S Thomaidis.
      This study presents the development and validation of a comprehensive high-resolution mass spectrometry (HRMS) methodology for the detection of 771 pesticides in olive oil, using liquid chromatography with electrospray ionization, operating in positive and negative mode, and gas chromatography with atmospheric-pressure chemical ionization in positive mode, both coupled to quadrupole-time-of-flight mass spectrometry (LC-(ESI)-/GC-(APCI)-QTOF MS). Special reference is made to the post-acquisition evaluation step, in which all LC/GC-HRMS analytical evidence (i.e. mass accuracy, retention time, isotopic pattern, MS/MS fragmentation) is taken into account in order to successfully identify the compounds. The sample preparation of the method involves a QuEChERS-based protocol, common for both techniques, differentiated only on the reconstitution step, making the method highly applicable in routine analysis. A smart evaluation of method's performance was carried out, with 65 representative analytes comprising the validation set. The method was validated in terms of linearity, accuracy, matrix effect and precision, while the limits of detection and quantification of the method were estimated. Finally, twenty Greek olive oil samples were analysed in both analytical platforms and the findings included the pesticides lambda-cyhalothrin, chlorpyrifos, phosphamidon, pirimiphos-methyl and esprocarb at low ng g-1 level.
    DOI:  https://doi.org/10.1039/d4ay00181h
  12. J Chromatogr B Analyt Technol Biomed Life Sci. 2024 Apr 12. pii: S1570-0232(24)00133-8. [Epub ahead of print]1238 124125
    Simultaneous quantification and confirmation of oxycodone and its metabolites in equine urine using ultra-high performance liquid chromatography-tandem mass spectrometry.
    Youwen You, Jaclyn R Missanelli, Rachel M Proctor, Joanne Haughan, Mary A Robinson.
      Oxycodone, an opioid commonly used to treat pain in humans, has the potential to be abused in racehorses to enhance their performance. To understand the pharmacokinetics of oxycodone and its metabolites in horses, as well as to detect the illegal use of oxycodone in racehorses, a method for quantification and confirmation of oxycodone and its metabolites is needed. In this study, we developed and validated an ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method that can simultaneously quantify and confirm oxycodone and eight metabolites in equine urine. Samples were subjected to enzymatic hydrolysis and then liquid-liquid extraction using ethyl acetate. The analyte separation was achieved on a Hypersil Gold C18 sub-2 µm column and analytes were detected on a triple quadrupole mass spectrometer. The limit of detection (LOD) and lower limit of quantification (LLOQ) were 25-50 pg/mL and 100 pg/mL, respectively. Excellent linearity of the calibration curves was observed over a range of 100-10000 pg/mL for all nine analytes. Retention time, signal-to-noise ratio, and product ion ratios were utilized as confirmation criteria, with the limits of confirmation (LOC) ranging from 100 to 250 pg/mL. The data from a pilot pharmacokinetic (PK) study suggested that oxycodone metabolites have longer detection periods in equine urine compared to oxycodone itself; thus, the detection of metabolites in equine urine extends the ability to detect oxycodone exposure in racehorses.
    Keywords:  Confirmation; Equine urine; LC-MS/MS; Metabolites; Oxycodone; Quantification
    DOI:  https://doi.org/10.1016/j.jchromb.2024.124125
  13. J Chromatogr B Analyt Technol Biomed Life Sci. 2024 Apr 09. pii: S1570-0232(24)00131-4. [Epub ahead of print]1238 124123
    Derivatization-free determination of chiral plasma pharmacokinetics of MDMA and its enantiomers.
    Dino Luethi, Deborah Rudin, Isabelle Straumann, Jan Thomann, Isidora Avedisian, Matthias E Liechti, Urs Duthaler.
      3,4-Methylenedioxymethamphetamine (MDMA) is an entactogen with therapeutic potential. The two enantiomers of MDMA differ regarding their pharmacokinetics and pharmacodynamics but the chiral pharmacology of MDMA needs further study in clinical trials. Here, an achiral and an enantioselective high performance liquid chromatography-tandem mass spectrometry method for the quantification of MDMA and its psychoactive phase I metabolite 3,4-methylenedioxyamphetamine (MDA) in human plasma were developed and validated. The analytes were detected by positive electrospray ionization followed by multiple reaction monitoring. The calibration range was 0.5-500 ng/mL for the achiral analysis of both analytes, 0.5-1,000 ng/mL for chiral MDMA analysis, and 1-1,000 ng/mL for chiral MDA analysis. Accuracy, precision, selectivity, and sensitivity of both bioanalytical methods were in accordance with regulatory guidelines. Furthermore, accuracy and precision of the enantioselective method were maintained when racemic calibrations were used to measure quality control samples containing only one of the enantiomers. Likewise, enantiomeric calibrations could be used to reliably quantify enantiomers in racemic samples. The achiral and enantioselective methods were employed to assess pharmacokinetic parameters in clinical study participants treated with racemic MDMA or one of its enantiomers. The pharmacokinetic parameters assessed with both bioanalytical methods were comparable. In conclusion, the enantioselective method is useful for the simultaneous quantification of both enantiomers in subjects treated with racemic MDMA. However, as MDMA and MDA do not undergo chiral inversion, enantioselective separation is not necessary in subjects treated with only one of the enantiomers.
    Keywords:  Bioanalysis; Enantiomer; Enantioselective; MDMA; Pharmacokinetics
    DOI:  https://doi.org/10.1016/j.jchromb.2024.124123
  14. J Pharm Anal. 2024 Mar;14(3): 295-307
    Chemical derivatization strategies for enhancing the HPLC analytical performance of natural active triterpenoids.
    Xiao-Feng Huang, Ying Xue, Li Yong, Tian-Tian Wang, Pei Luo, Lin-Sen Qing.
      Triterpenoids widely exist in nature, displaying a variety of pharmacological activities. Determining triterpenoids in different matrices, especially in biological samples holds great significance. High-performance liquid chromatography (HPLC) has become the predominant method for triterpenoids analysis due to its exceptional analytical performance. However, due to the structural similarities among botanical samples, achieving effective separation of each triterpenoid proves challenging, necessitating significant improvements in analytical methods. Additionally, triterpenoids are characterized by a lack of ultraviolet (UV) absorption groups and chromophores, along with low ionization efficiency in mass spectrometry. Consequently, routine HPLC analysis suffers from poor sensitivity. Chemical derivatization emerges as an indispensable technique in HPLC analysis to enhance its performance. Considering the structural characteristics of triterpenoids, various derivatization reagents such as acid chlorides, rhodamines, isocyanates, sulfonic esters, and amines have been employed for the derivatization analysis of triterpenoids. This review comprehensively summarized the research progress made in derivatization strategies for HPLC detection of triterpenoids. Moreover, the limitations and challenges encountered in previous studies are discussed, and future research directions are proposed to develop more effective derivatization methods.
    Keywords:  Derivatization; HPLC; Quantification; Triterpenoid
    DOI:  https://doi.org/10.1016/j.jpha.2023.07.004
  15. J Proteome Res. 2024 Apr 19.
    How Much Storage Precision Can Be Lost: Guidance for Near-Lossless Compression of Untargeted Metabolomics Mass Spectrometry Data.
    Junjie Tong, Miaoshan Lu, Ruimin Wang, Shaowei An, Jinyin Wang, Tong Wang, Cong Xie, Changbin Yu.
      Several lossy compressors have achieved superior compression rates for mass spectrometry (MS) data at the cost of storage precision. Currently, the impacts of precision losses on MS data processing have not been thoroughly evaluated, which is critical for the future development of lossy compressors. We first evaluated different storage precision (32 bit and 64 bit) in lossless mzML files. We then applied 10 truncation transformations to generate precision-lossy files: five relative errors for intensities and five absolute errors for m/z values. MZmine3 and XCMS were used for feature detection and GNPS for compound annotation. Lastly, we compared Precision, Recall, F1 - score, and file sizes between lossy files and lossless files under different conditions. Overall, we revealed that the discrepancy between 32 and 64 bit precision was under 1%. We proposed an absolute m/z error of 10-4 and a relative intensity error of 2 × 10-2, adhering to a 5% error threshold (F1 - scores above 95%). For a stricter 1% error threshold (F1 - scores above 99%), an absolute m/z error of 2 × 10-5 and a relative intensity error of 2 × 10-3 were advised. This guidance aims to help researchers improve lossy compression algorithms and minimize the negative effects of precision losses on downstream data processing.
    Keywords:  GNPS; MZmine3; XCMS; compound annotation; feature detection; lossy compressors; mass spectrometry; precision losses; truncation transformations; untargeted metabolomics
    DOI:  https://doi.org/10.1021/acs.jproteome.3c00851
  16. J Steroid Biochem Mol Biol. 2024 Apr 11. pii: S0960-0760(24)00067-0. [Epub ahead of print] 106519
    Phytosterols in human serum as measured using a liquid chromatography tandem mass spectrometry.
    Yu Chun Teng, Marie Claire Gielen, Nina M De Gruijter, Coziana Ciurtin, Elizabeth C Rosser, Kersti Karu.
      Phytosterols are lipophilic compounds found in plants with structural similarity to mammalian cholesterol. They cannot be endogenously produced by mammals and therefore always originate from diet. There has been increased interest in dietary phytosterols over the last few decades due to their association with a variety of beneficial health effects including low-density lipoprotein cholesterol lowering, anti-inflammatory and anti-cancerous effects. They are proposed as potential moderators for diseases associated with the central nervous system where cholesterol homeostasis is found to be imperative (multiple sclerosis, dementia, etc.) due to their ability to reach the brain. Here we utilised an enzyme-assisted derivatisation for sterol analysis (EADSA) in combination with a liquid chromatography tandem mass spectrometry (LC-MSn) to characterise phytosterol content in human serum. As little as 100 fg of plant sterol was injected on a reversed phase LC column. The method allows semi-quantitative measurements of phytosterols and their derivatives simultaneously with measurement of cholesterol metabolites. The identification of phytosterols in human serum was based on comparison of their LC retention times and MS2, MS3 spectra with a library of authentic standards. Free campesterol serum concentration was in the range from 0.30 - 4.10µg/mL, β-sitosterol 0.16 - 3.37µg/mL and fucosterol was at lowest concentration range from 0.05 - 0.38µg/mL in ten individuals. This analytical methodology could be applied to the analysis of other biological fluids and tissues.
    DOI:  https://doi.org/10.1016/j.jsbmb.2024.106519
  17. Anal Chem. 2024 Apr 15.
    Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry by Matrix-Assisted Laser Desorption Ionization.
    Richard J Bell, David S Hage, Eric D Dodds.
      Two-dimensional Fourier transform ion cyclotron resonance (2D FTICR) mass spectrometry is a developing form of data-independent acquisition that allows for the simultaneous fragmentation and correlation of fragment ions to their precursors across a range of m/z values. The modern usage of 2D FTICR is performed using electrospray ionization (ESI) as the dried droplet preparation for matrix-assisted laser desorption ionization (MALDI) does not produce a consistent packet of ions over a number of scans. This work uses pneumatic spray techniques from mass spectrometry imaging to create a homogeneous surface for use with MALDI as an ionization source for 2D FTICR. A mixture of peptides and matrix was deposited onto a glass slide using an HTX pneumatic sprayer. MALDI was then used to ionize the peptide mixture for use with a standard 2D FTICR pulse sequence. The generated 2D spectrum reveals comparable structural information to spectra collected in a 1D experiment. Artifacts observed in the collected 2D MALDI spectra do not significantly differ from those expected from 2D ESI spectra.
    DOI:  https://doi.org/10.1021/acs.analchem.3c05601
  18. Plant Cell Physiol. 2024 Apr 15. pii: pcae038. [Epub ahead of print]
    Analytical Methods for Brassinosteroid Analysis: Recent Advances and Applications.
    Jana Oklestkova, Miroslav Kvasnica, Miroslav Strnad.
      Brassinosteroids (BRs) are plant steroidal hormones that play crucial roles in plant growth and development. Accurate quantification of BRs in plant tissues is essential for understanding their biological functions. This study presents a comprehensive overview of the latest methods used for the quantification of BRs in plants. We discuss the principles, advantages, and limitations of various analytical techniques, including immunoassays, gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS) that are used for the detection and quantification of BRs from complex plant matrices. We also explore the use of isotopically labeled internal standards to improve the accuracy and reliability of BR quantification.
    Keywords:  Brassinosteroids; chemical synthesis; chromatography; immunoassays; mass spectrometry; quantification
    DOI:  https://doi.org/10.1093/pcp/pcae038
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