bims-metlip Biomed News
on Methods and protocols in metabolomics and lipidomics
Issue of 2026–07–12
forty-two papers selected by
Sofia Costa, Matterworks
  1. [Simultaneous determination of five common pyrethroid metabolites in urine using liquid-liquid extraction coupled with ultra performance liquid chromatography-tandem mass spectrometry].
  2. AI-assisted versus manual sustainability assessment of a high-throughput LC-MS/MS method for psychotropic and OTC drugs of abuse in human plasma.
  3. Overcoming Stability Challenge During the Quantification of SHR6508 in Human Plasma by LC-MS/MS.
  4. Development and application of a liquid chromatography-tandem mass spectrometry method for the analysis of Areca nut alkaloids in rat plasma for a toxicokinetic study.
  5. Orbitrap Collision Cross Section Measurements Enhance Isomer Annotations in Lipidomics.
  6. LC-MS-Based Metabolomics and Proteomics Sample Preparation of Urine: Methods and Multi-Omics Integration.
  7. [Determination of 29 per- and polyfluoroalkyl substances and 22 organophosphate esters and diester metabolites in human serum by high-throughput solid-phase extraction- ultra performance liquid chromatography- high resolution mass spectrometry].
  8. Method development and validation for determination of entinostat in human plasma and its application in breast cancer patients.
  9. Enhanced Sensitivity and Selectivity for the Quantification and Organ-Specific Distribution of Imidacloprid in Zebrafish Tissues via UHPLC-MS.
  10. Quantitative Profiling and Metabolic Study of Caffeoylquinic Acids and Their Metabolites by Liquid Chromatography-Tandem Mass Spectrometry in Rats and Laying Hens.
  11. Clinical validation of an automated extraction protocol and liquid chromatography single quadrupole mass spectrometry (LC-MS) method for plasma vitamins A and E analysis.
  12. Data-Independent Acquisition for Improved Compound Annotation in MALDI MS Imaging.
  13. Automated Pixel-Wise Recalibration for Improving Mass Accuracy and Peak Assignment in MALDI Mass Spectrometry Imaging.
  14. Development and validation of a green dispersive liquid-liquid microextraction-LC-MS/MS method for sotalol quantification in human plasma using central composite design optimization and pharmacokinetic application.
  15. Development and Validation of a UPLC-MS/MS for Determination of Loureirin D in Rat Plasma and Its Application to Pharmacokinetics.
  16. An Overview of Pterin Analysis in Biological Samples: From Occurrence and Properties to Sample Pretreatment Combined With Hyphenated Separation Techniques.
  17. Simultaneous Quantification of Ceramides and Sphingosine-1-Phosphate in Serum by LC-MS/MS with Application to Alcohol Intoxication Cases.
  18. Incorporation of Co-Cyromazine Complexes Onto Halloysite Nanotubes as a Spin-Tip Solid-Phase Extraction Sorbent for Determining Hydrophilic B Vitamins in Functional Foods.
  19. LC-MS FADE: Leveraging Untargeted Lipidomics Data for Fatty Acid Profiling.
  20. Analytical challenges in mapping the subcellular metabolome and lipidome.
  21. Development of a Tapping-Mode Scanning Probe Electrospray Ionization Platform for High-Sensitivity and Long-Term Stability in Single-Cell Mass Spectrometry Imaging of Tissue.
  22. Matrix Effects and Analytical Instability in Pharmaceutical Bioanalysis: Current Challenges and Future Directions.
  23. Beyond the Fixed Charge: A New On-Tissue Derivatisation Strategy Employing Photoionisable Chromophores for Mass Spectrometry Imaging of Amino-Containing Metabolites.
  24. Tandem column coupling in supercritical fluid chromatography-mass spectrometry for the multiresidue analysis of pesticides in complex Allium vegetables.
  25. HPLC-MS method for tracing multiclass PPCPs in soil and water: optimization of ionization and extraction strategies.
  26. Enhanced determination of 85 mycotoxins in challenging root and rhizome herbal medicines using online segmented multi-dimensional liquid chromatography-tandem mass spectrometry.
  27. An m/z- and Intensity-Based HRMS Clustering Algorithm Targeted toward Single-Cell Metabolomics.
  28. EXPRESS: Precursor/Fragment Ion Identification from Bulk Analysis of a Mixture through Two-Dimensional Correlation Mass Spectrometry.
  29. Development of an optimised method for the analysis of human blood plasma samples by atmospheric solids analysis probe mass spectrometry.
  30. Hybridization LC-MS/MS: An alternative platform to enable specific and sensitive quantification of Antibody-ASO conjugates.
  31. High-throughput multi-residue determination of 157 pesticides in wine using QuEChERS-UPLC-MS/MS for routine monitoring applications.
  32. Paper Spray Mass Spectrometry for Rapid Toxicology Targeted Screening of Emergency Department Samples: A Research Study.
  33. Determination of Pyrrolizidine Alkaloids and Their N‑Oxides in Bee Pollen by Accelerated Solvent Extraction Followed by Magnetic Covalent Organic Framework-Based Offline Purification and Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry.
  34. [Validation Study on a Rapid Method for Simultaneous Determination of Pesticide Residues in Livestock Products by LC-MS/MS].
  35. [Simultaneous determination of glycerol， acetic acid， and sodium bisulfite in compound amino acid injection （14AA） using ion exclusion chromatography].
  36. [Surveillance of the Levels of Naturally Derived Benzoic Acid in Fresh Foods ②Examination of Qualitative and Quantitative Improvements Using Citrus Fruits in the Dialysis Method].
  37. Comprehensive Isomer-Resolved Ganglioside Profiling by HILIC-nanoESI-MS/MS.
  38. Hybrid dissociation modes in a portable ion trap mass spectrometer for enhanced specificity in complex mixture analysis.
  39. Reverse Biotransformation-Guided Annotation of Untargeted MS/MS Features: A Computational Framework for Candidate Enzyme and Gene Hypothesis Generation.
  40. EXPRESS: Identification of Unknown Peaks in Mass Spectra Based on the Characteristic Isotopic Pattern via the Hilbert-Noda Matrix.
  41. Green and Robust RP-HPLC for Simultaneous Quantification of Gallic, Ferulic, and Caffeic Acids in Human Plasma via Box-Behnken Design-Based Optimization.
  42. Evaluating Different C18 Columns for the LC Separation of Δ9-THC and Other Related Cannabinoids.
  1. Se Pu. 2026 Jul;44(7): 777-784
    [Simultaneous determination of five common pyrethroid metabolites in urine using liquid-liquid extraction coupled with ultra performance liquid chromatography-tandem mass spectrometry].
    Xiao-Mei Zhang, Xiang-Juan Meng, Yue Hu, Xiao-Dong Liu.
      Pyrethroids are extensively employed in agricultural pest management and household sanitation practices. However， their widespread use has raised concerns as they pose a multitude of health risks to humans. Consequently， the development of precise， highly sensitive， and efficient biomonitoring techniques for evaluating internal exposure levels of pyrethroids across different populations has emerged as a paramount goal in the field of environmental exposure and health effect research. This study developed a method using ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） for the simultaneous determination of five common pyrethroid metabolites in urine， with sample pretreatment involving hydrochloric acid hydrolysis and liquid-liquid extraction. The method was optimized for mass spectrometric acquisition parameters and liquid chromatography separation conditions. Chromatographic separation was successfully accomplished utilizing a BEH C18 column （100 mm×2.1 mm，1.7 μm）. Mass spectrometric data were acquired in negative ion mode under multiple reaction monitoring （MRM） conditions. Among the analytes， trans-3-（2，2-dichlorovinyl）-2，2-dimethylcyclopropanecarboxylic acid （trans-DCCA） and cis-3-（2，2-dichlorovinyl）-2，2-dimethylcyclopropanecarboxylic acid （cis-DCCA） are isomers， as are 2-phenoxybenzoic acid （2-PBA） and 3-phenoxybenzoic acid （3-PBA）， and they share identical MS acquisition parameters. Identification was based on reference standards and retention times. The mobile phase consisted of 0.1% acetic acid in water （A） and acetonitrile （B）. The gradient elution program was as follows： 0-0.5 min， 10%B； 0.5-4.5 min， 10%B-70%B； 4.5-5 min， 70%B-100%B； 5-7 min， 100%B； 7-8 min， 100%B-10%B； 8-10 min， 10%B. The optimization of urine sample pretreatment conditions was divided into two parts： hydrolysis and extraction. Using the recoveries of target analytes as the evaluation metric， parameters including the dosage of hydrolysis reagent， hydrolysis temperature and duration， as well as the type， dosage， and extraction time of the extraction solvent were systematically optimized. The optimized pretreatment protocol is delineated as follows： Initially， 40 µL of the 2-PBA internal standard working solution was precisely added to 1 mL of urine sample， followed by thorough mixing to ensure homogeneity. Subsequently， 150 µL of hydrochloric acid （2 mol/L） was introduced to facilitate hydrolysis， which was allowed to proceed at ambient room temperature for a duration of 30 min. Finally， extraction was carried out using 2 mL of ethyl acetate， accompanied by vigorous shaking for 30 min to maximize extraction efficiency. Following centrifugation， the organic phase was separated， evaporated to near dryness， and reconstituted with 1.0 mL of acetonitrile prior to instrumental analysis. The matrix effects were evaluated using pure solvent and matrix-matched standards. Among the five analytes， three exhibited a moderate matrix effect， while two showed a weak matrix effect. The recovery performance using 2-PBA as an internal standard was also assessed. Consequently， a combination of the working curve and the internal standard method was selected for the quantification of the target analytes. Based on this， the methodological parameters of the method were validated. The results indicate that the five pyrethroid metabolites exhibited good linearity， with correlation coefficients of the calibration curves all exceeding 0.995. The limits of detection （LODs） ranged from 0.13 ng/mL to 1.32 ng/mL， and the limits of quantification （LOQs） ranged from 0.44 ng/mL to 4.39 ng/mL. The average recoveries of the samples at three spiked levels of 20， 50， and 80 ng/mL ranged from 91.0% to 102.0%. The intra-batch precision was between 1.1% and 8.1%， while the inter-batch precision was between 1.1% and 4.6%. Sample stability was demonstrated for at least one week when stored at 4 ℃. The established method was applied to analyze 18 urine samples from the general population. Neither cis-DCCA nor 4-fluoro-3-phenoxybenzoic acid （4F-3PBA） was detected in any sample. The mass concentration of 3-PBA ranged from 0.69 ng/mL to 1.59 ng/mL， with a detection rate as high as 88.9%. These results are largely consistent with screening studies on human pyrethroid metabolite levels reported in domestic and international literature in terms of both the detection rate and mass concentration range of 3-PBA. The presence of 3-PBA may originate from household insecticide exposure or dietary sources. The method demonstrates simple and efficient sample pretreatment， strong cost-effectiveness， low LODs， and high accuracy and precision. It can therefore serve as a reliable technical reference for monitoring and exposure assessment in various populations， particularly sensitive groups such as the general population， pregnant women， and children.
    Keywords:  liquid-liquid extraction （LLE）; metabolites; pyrethroids （PYRs）; ultra performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS）; urine
    DOI:  https://doi.org/10.3724/SP.J.1123.2025.10017
  2. Sci Rep. 2026 Jul 06. pii: 20807. [Epub ahead of print]16(1):
    AI-assisted versus manual sustainability assessment of a high-throughput LC-MS/MS method for psychotropic and OTC drugs of abuse in human plasma.
    Hend Z Yamani, Khaled Hesham, Shereen M Tawakkol, Lobna A Hussein, Nesma M Fahmy.
      A rapid, sensitive, and selective LC-MSMS method was developed and validated for the quantification of dextromethorphan (DXM), pseudoephedrine (PSE), olanzapine (OLA), and fluoxetine (FLU) in human plasma. Mixture 1 (DXM/PSE) and mixture 2 (OLA/FLU) are fixed-dose combinations commonly misused at high doses for their euphoric effects. The proposed method employed a simple protein precipitation technique for sample preparation, using a cost-effective cross-over internal standard strategy; OLA for mixture 1 and DXM for mixture 2. Chromatographic separation was achieved on a Hypersil GOLD column (100 × 3 mm, 1.9 µm) using an isocratic mobile phase consisting of acetonitrile and 0.1% formic acid (70:30, v/v) at a flow rate of 0.3 mL/min. The short runtime of 2.5 min enables high-throughput analysis. Detection was performed in positive ionization mode using multiple reaction monitoring (MRM). The method exhibited linearity over concentration ranges of 0.05-25.0 ng/mL for DXM, 2.0-1000.0 ng/mL for PSE, 0.2-20.0 ng/mL for OLA, and 0.5-50.0 ng/mL for FLU with lower limits of quantification (LLOQs) of 0.05, 2.0, 0.2, and 0.5 ng/mL, respectively. The method was successfully validated in accordance with FDA and ICH bioanalytical method validation guidelines, demonstrating satisfactory selectivity, accuracy, and precision. The validated method demonstrated high extraction recovery (> 90%), limited, reproducible matrix effects (IS-normalized matrix factor CV ≤ 15%). This study represents a novel application of artificial intelligence (AI)-assisted evaluation, utilizing a universally accessible model to assess the greenness and whiteness of the proposed LC-MS/MS method through the Auto-AGREE and Auto-RGB 12 frameworks. The AI-generated assessments demonstrated high agreement with traditional metrics, highlighting the potential of AI tools to provide rapid and objective holistic sustainability evaluations for the global analytical community.
    Keywords:  AI-assisted; Dextromethorphan; Fluoxetine; LC–MS/MS; Olanzapine; Pseudoephedrine
    DOI:  https://doi.org/10.1038/s41598-026-59794-z
  3. Biomed Chromatogr. 2026 Aug;40(8): e70555
    Overcoming Stability Challenge During the Quantification of SHR6508 in Human Plasma by LC-MS/MS.
    Yuan Wu, Tao Chen, Kan Zhong, Laiyou Wang.
      SHR6508, a novel calcimimetic agent, is currently being developed for treating secondary hyperparathyroidism in chronic kidney disease (CKD) patients requiring maintenance hemodialysis. For the purpose of quantifying SHR6508 in human plasma, a sensitive and reliable LC-MS/MS method was first developed and successfully validated. Since SHR6508 is a disulfide bond-containing peptide, ascorbic acid was supplemented into blood samples during collection to prevent thiol-disulfide exchange reactions. Plasma matrix samples were processed by protein precipitation with a water-acetonitrile solution (1:4, v/v) containing 0.05% formic acid. Chromatographic separation was conducted on an XBridge Peptide BEH C18 column (4.6 × 100 mm, 5.0 μm) under gradient elution with water and methanol, each containing 0.1% trifluoroacetic acid. SHR6508 was quantified by tandem mass spectrometry in positive electrospray ionization using multiple reaction monitoring with transitions of m/z 532.0 → 455.5 for SHR6508 and m/z 537.0 → 456.5 for SHR180296 (isotope-labelled internal standard). The quantification linear range was 1.00-1000 ng/mL. All validation parameters including selectivity, carryover, precision, accuracy, recovery, and matrix effect fell within the predefined acceptance criteria. The stabilization strategy developed in this work may also offer valuable insights for the collection and analysis of other disulfide bond-containing peptide drugs.
    Keywords:  LC–MS/MS; SHR6508; peptide; stability
    DOI:  https://doi.org/10.1002/bmc.70555
  4. J Chromatogr B Analyt Technol Biomed Life Sci. 2026 Jun 30. pii: S1570-0232(26)00287-4. [Epub ahead of print]1281 125198
    Development and application of a liquid chromatography-tandem mass spectrometry method for the analysis of Areca nut alkaloids in rat plasma for a toxicokinetic study.
    Su-Kyung Moon, Jung Eun Min, Hyun-Deok Cho, Seung Eui Min, Ji-Min Park, Sang-Jin Park, Hyung Min Kim, Kang-Hyun Han, Han Young Eom.
      Areca nut (Areca catechu L., Arecaceae) contains bioactive alkaloids, including arecoline, arecaidine, and guvacoline, which are associated with pharmacological and toxicological effects. A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for simultaneous quantification of these alkaloids in rat plasma and was applied to a toxicokinetic study. Chromatographic separation was achieved on a reversed-phase C18 column using gradient elution with aqueous and organic mobile phases containing a volatile acid modifier. Detection was performed by electrospray ionization in the positive ion mode with multiple reaction monitoring, and plasma samples were prepared by protein precipitation. The method was validated according to the current bioanalytical guidelines. The calibration curves showed good linearity (r > 0.99) over the tested ranges, the within- and between-run accuracy and precision were within ±15% (±20% at lower limit of quantification (LLOQ)), and the selectivity, carry-over, recovery, matrix effect, dilution integrity, and stability were acceptable. The LLOQs were 10 ng/mL for arecoline and guvacoline, and 100 ng/mL for arecaidine. The validated method was successfully applied for a toxicokinetic study in rats, and plasma concentration-time profiles of all analytes were characterized. These results show that the developed method is suitable for the quantitative determination of arecoline, arecaidine, and guvacoline in plasma and can be used in toxicokinetic and pharmacokinetic studies.
    Keywords:  Areca nut alkaloids; Arecaidine; Arecoline; Guvacoline; LC–MS/MS; Method validation; Rat plasma; Toxicokinetics
    DOI:  https://doi.org/10.1016/j.jchromb.2026.125198
  5. bioRxiv. 2026 Jul 03. pii: 2026.07.03.735735. [Epub ahead of print]
    Orbitrap Collision Cross Section Measurements Enhance Isomer Annotations in Lipidomics.
    Ziqin Ni, Konstantin Ayzikov, Alexander Makarov, Samuel Moore, David A Gaul, Kyle L Fort, Facundo M Fernández.
      Despite advances in high-resolution mass spectrometry (HRMS), confident lipid annotation remains challenging due to the extensive chemical diversity of the lipidome and the prevalence of isomeric species. Ion mobility collision cross section (CCS) measurements provide structural information that complements HRMS; however, not all HRMS platforms can perform these measurements, necessitating a trade-off among mass resolution, accuracy, and robustness. Here, we introduce a method to infer lipid CCS values directly from liquid chromatography (LC)-Orbitrap MS experiments ( Orbi CCS ). We show that Orbitrap mass analyzer pressure readings, and therefore CCS values, are influenced by the LC gradient solvent composition, requiring correction using isotopically labeled internal standards injected post-column. We also show that hundreds of lipid features can be assigned Orbi CCS values in a single LC run, with average precision better than 1% and an accuracy of 1-2% relative to reference DT CCS and TIMS CCS values. This excellent CCS accuracy not only enables more reliable annotation of lipid species in complex mixtures by matching Orbi CCS values to reference databases but also accelerates lipid structural elucidation based on the unknown's position in Orbi CCS -retention time- m/z space.
    DOI:  https://doi.org/10.64898/2026.07.03.735735
  6. Adv Exp Med Biol. 2026 ;1510 1-20
    LC-MS-Based Metabolomics and Proteomics Sample Preparation of Urine: Methods and Multi-Omics Integration.
    Muath Khairi Mousa, Nelson C Soares, Hugo M Santos.
      Urine is an ideal biological fluid due to the highly metabolomic and proteomic information it provides and its easy collection in large amounts. Urinary biomarkers reported for different types of diseases included the urological tract and systemic diseases. Although the most common approach in omics is single-omics studies, combining multi-omics biomarkers such as metabolomics, proteomics, transcriptomics, and genomics can improve diagnostic accuracy and provide deeper insights into disease mechanisms than single biomarkers. The gold standard technique for bioanalysis is liquid chromatography coupled to mass spectrometry (LC-MS/MS) due to its high sensitivity, specificity, and selectivity for the analysis of metabolites and proteins in complex biological samples. One of the most important aspects in metabolomics and proteomics is sample extraction and preparation before the analysis. Different types of metabolites and protein extraction methods can be used effectively for urine samples, including protein precipitation, liquid-liquid extraction, and solid-phase extraction. However, in the multi-omics approach integrating metabolomics and proteomics, sample preparation could be either individual for each or simultaneous for both from a single sample. In this chapter, we discuss aspects of LC-MS-based metabolomics and proteomics sample preparation, as well as their integration for a multi-omics approach. In clinical practice, the reported sample preparation methods for bladder cancer metabolomics and proteomics were also discussed.
    Keywords:  Bladder cancer; LC-MS; Metabolomics; Multi-omics; Proteomics; Sample preparation; Urinary biomarkers
    DOI:  https://doi.org/10.1007/978-3-032-21638-0_1
  7. Se Pu. 2026 Jul;44(7): 764-776
    [Determination of 29 per- and polyfluoroalkyl substances and 22 organophosphate esters and diester metabolites in human serum by high-throughput solid-phase extraction- ultra performance liquid chromatography- high resolution mass spectrometry].
    Shi-Qi Zhao, Hao Ding, Xu-Wenqi Zhang, Min-Min Hou, Ting-Ting Zhou, Ya-Li Shi, Ya-Qi Cai.
      Monitoring pollutants in human blood is a crucial basis for assessing human exposure levels and health risks. Per- and polyfluoroalkyl substances （PFAS）， organophosphate esters （OPEs）， and their diester metabolites （di-OPEs） are widespread environmental co-contaminants with significant toxic effects， making it crucial to monitor their internal human exposure levels. However， existing studies have predominantly investigated these substances in isolation， lacking comprehensive research that simultaneously quantifies PFAS， OPEs， and di-OPEs in human serum. Based on the pretreatment method of 96-well solid phase extraction columns， this study compared three extraction columns and optimized the pretreatment steps to establish an ultra performance liquid chromatography-high resolution mass spectrometry （UPLC-HRMS） method for 29 PFAS， 17 OPEs， and 5 di-OPEs in human serum samples. Phree PLR 96-Wellplate was used as a cleanup plate. 300 µL of 1% formic acid in acetonitrile， 100 µL of the serum sample， and internal standards were added to the cleanup device in sequence. After standing for 5 minutes， the 96-well plate positive pressure device was used to press the mixture into the 96-well collection plate. Finally， the sample was eluted with 100 µL of 1% formic acid in acetonitrile. The eluate was collected and concentrated for the detection of PFAS， OPEs， and di-OPEs by UPLC-HRMS. PFAS and OPEs were detected using an Acclaim RSLC 120 C18 column， while di-OPEs were detected using an Acquity UPLC BEH C18 column. Both were subjected to gradient elution with methanol and 5 mmol/L ammonium acetate in water as the mobile phases. Sample ionization was performed using a heated electrospray ionization source （H-ESI）. PFAS and di-OPEs were analyzed in negative ion mode， while OPEs were analyzed in positive ion mode. Data acquisition was conducted in full-scan/data-dependent tandem mass spectrometry （Full MS/ddMS2） mode. Quantification was achieved using the internal standard calibration method to ensure measurement accuracy. The results showed that under the optimized conditions， the target compounds had good linear relationships in the range of 0.05-50 ng/mL （R2 > 0.99）， and the method detection limits （MDLs） of 29 PFAS， 17 OPEs and 5 di-OPEs were 0.000 120-0.274 ng/mL， 0.011 0-0.250 ng/mL， and 0.012 0-0.220 ng/mL， respectively， and the spiked recoveries were between 45.9% and 147.8%. The relative standard deviations （RSDs） were 1.2%-29.0%. Most PFAS and di-OPEs had matrix enhancement effects， and most OPEs had matrix inhibition effects. Among them， hexafluoropropylene oxide dimer acid （GenX） （196.5%） and trimethylphenyl phosphate （TMPP） （54.6%） had significant matrix enhancement and inhibition effects， respectively， which could be corrected with appropriate internal standards. The recoveries of these two substances after correction were 127.3% and 78.7%， respectively， which met the analysis requirements. The proposed approach offers significant practical benefits， combining straightforward operation with shortened extraction time and enhanced throughput， which was validated through analysis of 15 human serum samples collected in Jinan in 2024. The total contents of 29 PFAS were 6.71-379 ng/mL， with a median value of 22.9 ng/mL. Eight PFAS were detected with a detection frequency of 100.0%， with median contents of perfluorooctanoic acid （PFOA） and perfluorooctane sulfonate （PFOS） reaching 8.96 ng/mL and 4.07 ng/mL， respectively. The total contents of 17 OPEs were 0.015 0-10.5 ng/mL， with a median value of 2.81 ng/mL. The most frequently detected OPEs， with detection frequencies exceeding 60.0%， were triethyl phosphate （TEP）， tri-n-butyl phosphate （TnBP）， and triphenyl phosphate （TPHP）. The total contents of 5 di-OPEs were <MDL-0.443 ng/mL， with a median value of 0.015 0 ng/mL. Therefore， the combined exposure to these pollutants in human blood and its potential health risks demand serious attention.
    Keywords:  96-wellplate; organophosphate esters （OPEs）; per- and polyfluoroalkyl substances （PFAS）; serum; ultra performance liquid chromatography-high resolution mass spectrometry （UPLC-HRMS）
    DOI:  https://doi.org/10.3724/SP.J.1123.2025.07008
  8. RSC Adv. 2026 Jul 09.
    Method development and validation for determination of entinostat in human plasma and its application in breast cancer patients.
    Shuo Li, Yuxiang Xu, Jiameng Dong, Yushuo Qiu, Zhixuan Yang, Xiaonan Gao, Jinglin Gao, Zhangying Feng, Caixue Wang, Mingxia Wang.
      Entinostat is an oral histone deacetylase (HDAC) inhibitor used in HR+ breast cancer therapy, for which reliable plasma concentration monitoring is essential for dose optimization and toxicity management. This article described an ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the quantitative analysis of entinostat in human plasma. Samples were concentrated under vacuum after methanol precipitation and separated on a Kinetex C18 column (100 mm × 2.1 mm, 2.6 µm). The mobile phase consisted of acetonitrile and an aqueous solution containing 10 mM ammonium acetate and 0.01% formic acid. The quantitative ion pair for entinostat was m/z 377.2 → 104.0, and for carbamazepine it was m/z 237.1 → 194.1, used as an internal standard (IS). The calibration curves showed good linearity (r 2 > 0.99) across plasma concentrations ranging from 0.2 to 200 ng mL-1. Precision (RSD%) was within the range of 1.22-6.36%, accuracy ranged from 97.58% to 110.67%, the matrix effect ranged from 85% to 115%, and analyte recoveries ranged from 85% to 115%, meeting acceptable standards. This validated UPLC-MS/MS method was successfully applied to determine plasma concentration in seven breast cancer patients receiving 3 mg weekly doses of entinostat, providing a powerful tool for clinical pharmacokinetic studies and therapeutic drug monitoring.
    DOI:  https://doi.org/10.1039/d6ra03621j
  9. J Mass Spectrom. 2026 Aug;61(8): e70082
    Enhanced Sensitivity and Selectivity for the Quantification and Organ-Specific Distribution of Imidacloprid in Zebrafish Tissues via UHPLC-MS.
    Jiarui Zhang, Sijia Tong, Hongjie Ju, Hui Miao, Yujuan Gong, Meiyun Shi, Lei Yin.
      Neonicotinoid insecticides, such as imidacloprid, pose significant risks to aquatic ecosystems due to their widespread use and potential for accumulation. In this study, a sensitive and robust analytical strategy based on ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS3) was developed and validated for the determination of imidacloprid in multiple complex zebrafish biological matrices, including the muscle, liver, intestine, heart, brain, and gills. By harnessing the unique selectivity of the MS3 acquisition mode, the method effectively eliminated endogenous matrix interferences and achieved a 243-fold enhancement in signal intensity compared to the conventional multiple reaction monitoring (MRM) mode. The sample pretreatment utilized a streamlined protein precipitation approach with methanol, ensuring high extraction efficiency and reproducibility across all tissues. The method was fully validated according to FDA guidelines, demonstrating excellent linearity, accuracy, and precision. Furthermore, the practical application of this assay in a tissue distribution study revealed a non-uniform accumulation pattern of imidacloprid, with the highest concentrations observed in the muscle and intestine, and the lowest in the heart. These findings provide a powerful tool and essential empirical data for further biodistribution investigations and environmental risk assessments of trace-level contaminants in micro-gram level biological samples.
    Keywords:  UHPLC–MS3; imidacloprid; tissue accumulation; tissue distribution; zebrafish
    DOI:  https://doi.org/10.1002/jms.70082
  10. J Sep Sci. 2026 Jul;49(7): e70485
    Quantitative Profiling and Metabolic Study of Caffeoylquinic Acids and Their Metabolites by Liquid Chromatography-Tandem Mass Spectrometry in Rats and Laying Hens.
    Sichao Wang, Wenjie Tian, Xiaohui Feng, Huiyan Zhang, Youyou Yang, Junmin Zhang.
      Caffeoylquinic acids are natural polyphenolic compounds with notable antioxidant and anti-inflammatory activities. This study developed and validated a sensitive high-performance liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of isochlorogenic acid A (ICQA) and 22 metabolites in serum. The method exhibited excellent sensitivity with limits of quantification of 0.625-1.25 µg/L (signal-to-noise ratio = 10), inter/intra-day precision below 15%, and comprehensive coverage of phase I/II and microbial metabolites. Application of the method in rats and laying hens demonstrated its robustness for pharmacokinetic profiling and cross-species validation, revealing a triphasic metabolic pattern of ICQA, the consistent metabolic endpoints of the accumulation of microbial metabolites, and a critical role of gut microbiota in ICQA metabolism. The developed platform provides a reliable analytical tool for comprehensive metabolism studies of phenolic compounds, with high throughput and reproducibility.
    Keywords:  caffeoylquinic acid; isochlorogenic acid A; liquid chromatography‐tandem mass spectrometry; metabolism; quantification
    DOI:  https://doi.org/10.1002/jssc.70485
  11. Clin Chem Lab Med. 2026 Jul 10.
    Clinical validation of an automated extraction protocol and liquid chromatography single quadrupole mass spectrometry (LC-MS) method for plasma vitamins A and E analysis.
    Rowan Hellier, Lesley Heirene, Stuart J Moat.
       OBJECTIVES: Quantitation of plasma vitamins A and E is essential for assessing nutritional status. Traditional methods typically involve liquid-liquid extraction followed by high-performance liquid chromatography with UV detection (HPLC-UV). In this study, we evaluated an automated sample extraction-method paired with liquid chromatography-single quadrupole mass spectrometry (LC-MS) as an alternative analytical approach.
    METHODS: Plasma samples were extracted using Oasis PRiME HLB µElution Plates automated on a Tecan Liquid-Handling Platform and analysed using LC-MS. Injection-to-injection time was 5-min. Method performance was assessed by comparison with the Chromsystems™ Vitamin A and E HPLC-UV Kit, using patient specimens (n=70), ClinChek® Controls, and external quality assessment (EQA) materials.
    RESULTS: The developed method demonstrated acceptable inter-assay imprecision (CV≤5 %). The bias compared to the HPLC-UV method for vitamin A was 5.67 % and -0.15 % for vitamin E. Good agreement was observed for both vitamins (concordance correlation coefficients (CCC) >0.950). The assay was linear up to 12 μmol/L for vitamin A and 125 μmol/L for vitamin E. Using EQA materials, the mean bias for both analytes was <4 %. The lower limit of quantification (LLOQ) was 0.16 μmol/L for vitamin A and 0.47 μmol/L for vitamin E. Extracts stored at 4 °C and -20 °C were stable for 5 and 14 days, respectively. The analytical column demonstrated good retention time stability (<3.0 % change for both analytes) and was suitable for >1,500 injections.
    CONCLUSIONS: This method demonstrated robust analytical performance and good agreement with HPLC-UV. Our approach confers practical advantages over a manual based extraction and HPLC-UV analysis including analytical selectivity and workflow time efficiency.
    Keywords:  automation; liquid chromatography; mass spectrometry; vitamins A and E
    DOI:  https://doi.org/10.1515/cclm-2026-0108
  12. J Am Soc Mass Spectrom. 2026 Jul 10.
    Data-Independent Acquisition for Improved Compound Annotation in MALDI MS Imaging.
    Carmen Paschke, Kerstin Strupat, Carolin M Morawietz, Karl-Christian Schaefer, Christoph Henrich, Bernhard Spengler.
      Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) enables spatial mapping of biomolecules within biological tissues, where conventional MS1-based workflows often result in ambiguous compound annotations. Data-dependent acquisition (DDA) can improve annotation specificity but is biased toward high-abundant ions and lacks reproducibility. Here, we present a novel MALDI MSI workflow integrating data-independent acquisition (DIA) to obtain both spatial and fragmentation information. In this approach, MS1 and DIA MS2 spectra are acquired alternately across the sample without prior knowledge of compound localization. Each image pixel consists of one MS1 and several DIA MS2 subpixels, providing both high spatial resolution for MS1 data and broad m/z coverage. Using small, randomized m/z isolation windows reduces spectral overlap and improves fragment-ion specificity. Data were processed using an extended Compound Discoverer, integrating mzCloud and LipidSearch for compound annotation. Applied to tissue of the parasitic worm Fasciola hepatica, this workflow produced detailed lipid maps and improved annotation confidence by combining precursor-mass, DIA MS2, and spatial-correlation information. Our results demonstrate that DIA offers a flexible strategy to integrate fragmentation information into MALDI MSI, expanding its capabilities for spatial metabolomics.
    DOI:  https://doi.org/10.1021/jasms.6c00128
  13. J Am Soc Mass Spectrom. 2026 Jul 04.
    Automated Pixel-Wise Recalibration for Improving Mass Accuracy and Peak Assignment in MALDI Mass Spectrometry Imaging.
    Yuhao Fang, Kai Wu, Sujun Yan, Zilong Chen, Xinhai Zhu.
      Mass misalignment remains a major limitation in axial MALDI-TOF mass spectrometry imaging (MSI), leading to degraded mass accuracy, peak broadening, and reduced reliability of spatial molecular interpretation. Here, we present a fully automated pixel-level postacquisition recalibration framework that improves mass alignment while preserving single-pixel spectral fidelity. The method employs a "one-pixel, one-model" strategy using high-confidence endogenous calibration reference features, combined with dynamic peak matching and RANSAC (random sample consensus)-based robust regression, to correct both systematic and spatially heterogeneous mass drift. Applied to a mouse brain MSI data set (N = 33,903 pixels), the approach reduced the median absolute mass error from 28.1 to 5.6 ppm and restored spectral compactness in averaged spectra without introducing detectable peak-shape distortion. The improved mass alignment enabled the use of narrower extraction windows, resulting in enhanced spatial contrast and more reliable visualization of both high- and low-abundance lipid species. Notably, the method facilitated the resolution of overlapping spectral features and revealed biologically distinct lipid distributions that were obscured in uncalibrated data. These gains translated into improved consistency with reference-assisted annotation under stringent mass tolerances and enhanced interpretability in unsupervised multivariate analyses by reducing instrument-driven variance. The robustness and transferability of the framework were further demonstrated across independent data sets acquired under different matrix systems (DHB and NEDC), ion modes, and biological models (mouse brain and zebrafish), including data affected by substantial instrumental instability. In all cases, recalibration consistently reduced mass-error dispersion, improved spectral quality, and enhanced spatial signal extraction under fixed narrow-window conditions. Application of the strategy to different MALDI-MSI platforms also demonstrated its broad applicability and effectiveness in reducing mass errors. Overall, this pixel-level recalibration strategy provides a practical and broadly applicable postprocessing solution for improving mass accuracy, spectral fidelity, and spatial interpretability in MALDI-TOF MSI, thereby enabling more reliable molecular annotation and spatial analyses on widely accessible instrumentation.
    Keywords:  MALDI mass spectrometry imaging; mass accuracy; mass drift; peak assignment; pixel-level recalibration
    DOI:  https://doi.org/10.1021/jasms.6c00113
  14. Sci Rep. 2026 07 05. pii: 20570. [Epub ahead of print]16(1):
    Development and validation of a green dispersive liquid-liquid microextraction-LC-MS/MS method for sotalol quantification in human plasma using central composite design optimization and pharmacokinetic application.
    Ahmed Serag, Maram H Abduljabbar, Manal E Alosaimi, Alaa O Baryyan, Reem M Alnemari, Fotoon F Redwan, Atiah H Almalki.
      An LC-MS/MS method coupled with central composite design (CCD)-optimized dispersive liquid-liquid microextraction (DLLME) was developed and validated for sotalol quantification in human plasma according to ICH M10 guidelines. CCD with response surface methodology systematically evaluated four DLLME parameters - disperser solvent volume, extraction solvent volume, sample pH, and centrifugation time - identifying extraction solvent volume, pH, and disperser volume as dominant factors governing extraction efficiency. Optimal conditions of disperser volume 1200 µL, extraction solvent 300 µL, pH 10.0, and centrifugation time 3 min yielded predicted recovery of 95.29%, experimentally confirmed at 99-103%, with organic solvent consumption of 1.5 mL per sample representing a reduction compared to conventional SPE and LLE approaches. Chromatographic separation was achieved on a Poroshell 120 EC-C18 column (100 × 2.1 mm, 2.7 μm) with 4-min isocratic elution, and quantification employed MRM transitions m/z 273.1→255.1 for sotalol and m/z 267.2→145.1 for atenolol internal standard in positive ESI mode. The method demonstrated excellent linearity (1-1200 ng/mL, r² = 0.9994), sensitivity (LLOQ 1 ng/mL), acceptable accuracy and precision, and comprehensive stability under multiple storage conditions, in full compliance with ICH M10 acceptance criteria. Preliminary pharmacokinetic application in healthy volunteers following single oral 80 mg sotalol administration yielded Cmax 701 ± 53.8 ng/mL, t½ 10.1 ± 1.0 h, and AUC0→∞ 11,713 ± 1,345 ng·h/mL, broadly consistent with published literature values, supporting method applicability for therapeutic drug monitoring. Multi-metric sustainability assessment encompassing AGSA-prep (64/100), AGSA (65.28/100), CaFRI (69/100), BAGI (75.0/100), CACI (69/100), AMRI (71/100), and WECA (81%) demonstrated improved environmental performance relative to conventional extraction approaches, providing comprehensive sustainability characterization of the developed method.
    Keywords:  Central composite design; Dispersive liquid-liquid microextraction; Green analytical chemistry; LC-MS/MS; Sotalol
    DOI:  https://doi.org/10.1038/s41598-026-59711-4
  15. Biomed Chromatogr. 2026 Aug;40(8): e70547
    Development and Validation of a UPLC-MS/MS for Determination of Loureirin D in Rat Plasma and Its Application to Pharmacokinetics.
    Yi Zhou, Yuxin Wu, Chenyao Xu, Chenbin Zhang, Congcong Wen, Xianqin Wang, Jianbo Li.
      Loureirin D is a bioactive dihydrochalcone isolated from Dracaena resin with very high therapeutic value. A sensitive and high-throughput ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) method was developed for the quantitative analysis of loureirin D in rat plasma with only 50 μL of sample per assay. Sample extraction was protein precipitation using acetonitrile, and isoscoparin was used as internal standard (IS). Separation was achieved on the BEH C18 column with a gradient mobile phase of 0.1% (v/v) aqueous formic acid and acetonitrile. Detection was achieved with negative-ion electrospray ionization (ESI) detector in the multiple reaction monitoring (MRM) mode. The method was validated and proved to be linear in the concentration range of 2-2400 ng/mL (r ≥ 0.995), intraday and interday precision (RSD) was < 15%, and accuracy was 93.3%-110.1%. The extraction recovery was 88.7%-94.4%, and the matrix effects were 87.3%-92.9%. UPLC-MS/MS was used in pharmacokinetics in the rats after administration of loureirin D. The AUC(0-t) after intravenous administration (1 mg/kg) was 2074.7 ± 180.3 ng · h/mL, and AUC(0-t) after oral administration (5 mg/kg) was 563.4 ± 61.4 ng · h/mL; the absolute oral bioavailability was 5.4%. Pharmacokinetics showed rapid absorption, large Vz/F (52.7 ± 10.7 L/kg), high CLz/F (8.8 ± 0.9 L/h/kg), and extensive first-pass metabolism.
    Keywords:  UPLC‐MS/MS; loureirin D; oral bioavailability; pharmacokinetics
    DOI:  https://doi.org/10.1002/bmc.70547
  16. J Sep Sci. 2026 Jul;49(7): e70483
    An Overview of Pterin Analysis in Biological Samples: From Occurrence and Properties to Sample Pretreatment Combined With Hyphenated Separation Techniques.
    Jindřich Brejcha, Zuzana Bosakova.
      Pterins are a structurally diverse group of biologically active compounds within the pteridine family, with key roles in pigmentation, redox metabolism, light sensing, and cellular signaling across a wide range of organisms. Their quantification in biological samples is analytically demanding due to their high polarity, chemical instability, and the presence of multiple oxidation states. This review presents an integrated overview of pterin occurrence, structure, and physicochemical properties, followed by a detailed discussion of sample preparation strategies designed to ensure compound stability and analytical accuracy. Methods such as chemical oxidation, photochemical derivatization, and antioxidant stabilization are evaluated in the context of various biological matrices. We further examine state-of-the-art analytical techniques that combine separation with detection, including capillary electrophoresis, gas and liquid chromatography coupled with fluorescence, UV, electrochemical, or mass spectrometric detection. Particular attention is given to recent advances in LC-MS techniques, including both tandem mass spectrometry (LC-MS/MS) and high-resolution approaches (e.g., HPLC-Q/TOF-MS), which have greatly improved the sensitivity, selectivity, and throughput of pterin analysis, especially in combination with HILIC separation mode. These developments support the growing use of pterins as biomarkers in clinical diagnostics and physiological research, and underscore the importance of robust, matrix-appropriate analytical protocols tailored to the specific challenges posed by this compound class.
    Keywords:  biological samples; pretreatment; pterins; separation techniques
    DOI:  https://doi.org/10.1002/jssc.70483
  17. J Anal Toxicol. 2026 Jul 09. pii: bkag061. [Epub ahead of print]
    Simultaneous Quantification of Ceramides and Sphingosine-1-Phosphate in Serum by LC-MS/MS with Application to Alcohol Intoxication Cases.
    Yaqin Niu, Jingjing Cui, Lingjie Mo, Nianchang Zheng, Jiaxin Zhu, Junyi Lin, Yan Jiang.
      Ceramides and sphingosine-1-phosphate (S1P) are bioactive sphingolipids critically involved in the regulation of cell survival and death, whose homeostasis is disrupted by alcohol exposure. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous quantification of nine ceramide species and S1P in serum. Following protein precipitation, analytes were separated on a CSH C18 column within an 11-min chromatographic run. Calibration curves were linear over 5 to 500 ng/mL with R2 greater than 0.99 for all analytes. Intra- and inter-day accuracy and precision met acceptance criteria across all quality control levels. Extraction recoveries ranged from 79.51% to 109.23%, matrix effects were adequately compensated by stable isotope-labeled internal standards, and dilution integrity was confirmed across factors of 1:5, 1:10, and 1:20. The method was applied to a large cohort of serum samples from suspected alcohol-impaired driving cases stratified by blood alcohol concentration (BAC) into negative control, mild, moderate, and severe intoxication groups. Very long-chain ceramides including Cer 22:0, Cer 24:0, and Cer 24:1, as well as S1P, were consistently elevated in alcohol-exposed groups relative to the negative control. These findings indicate that circulating sphingolipid profiles reflect lipid metabolism alterations induced by ethanol exposure and may provide complementary information to blood alcohol concentration in the assessment of alcohol-associated cases.
    Keywords:  Alcohol intoxication; Ceramides; LC-MS/MS; Lipid metabolism; Sphingosine-1-phosphate
    DOI:  https://doi.org/10.1093/jat/bkag061
  18. J Sep Sci. 2026 Jul;49(7): e70489
    Incorporation of Co-Cyromazine Complexes Onto Halloysite Nanotubes as a Spin-Tip Solid-Phase Extraction Sorbent for Determining Hydrophilic B Vitamins in Functional Foods.
    Jiaheng Yan, Yifan Xu, Yihui Chen, Zhicheng Bai, Jianfeng He, Meikang Lei, Xiaoqiang Qiao, Tingting Wang.
      Quantifying hydrophilic B vitamins (B1 [(thiamine], B2 [riboflavin], and B3 [nicotinic acid]) in complex functional food matrices presents a significant challenge. Conventional sorbents, such as C18, often exhibit poor retention and low recoveries (50%-60%) due to weak hydrophilic interactions. To efficiently extract these target analytes from functional foods, a new sorbent with tailored hydrophilic affinity has been developed by incorporating Co-cyromazine complexes onto halloysite nanotubes. This composite was employed as the sorbent for a spin-tip solid-phase extraction method, which was coupled with liquid chromatography-tandem mass spectrometry analysis. Following comprehensive optimization and validation, the method demonstrates simplicity, accuracy, sensitivity, and cost-effectiveness. It requires only 10 mg (or 10 µL) of functional food sample, while delivering high recoveries (81.3%-107.8%) with good precision (relative standard deviations ≤10.7%). The limits of detection ranged from 0.4 to 2.5 ng/mL in liquid matrices and from 0.7 to 8.7 ng/g in solid matrices. Practical applicability was confirmed through the successful quantification of vitamins B1, B2, and B3 in various commercial functional foods. Consequently, the developed method provides a reliable and promising analytical tool for the determination of B vitamins, with the potential for extension to other hydrophilic analytes in biological and food matrices.
    Keywords:  B vitamins; cyromazine; hydrophilic interaction; liquid chromatography‐tandem mass spectrometry
    DOI:  https://doi.org/10.1002/jssc.70489
  19. Anal Chem. 2026 Jul 09.
    LC-MS FADE: Leveraging Untargeted Lipidomics Data for Fatty Acid Profiling.
    Jocelyn A Menard, Joshua A Roberts, Jacob H Clarke, Karlye E A Rudd, Christian A Rosales, Jeffrey C Smith.
      Fatty acid (FA) profiling has historically been accomplished via gas chromatography-mass spectrometry (GC-MS) and can be used in tandem with liquid chromatography-mass spectrometry (LC-MS) untargeted lipidomics workflows to comprehensively investigate global FA and lipid dynamics. This approach requires both GC-MS and LC-MS platforms, adding expense, acquisition time, and sample consumption, yet lacks the ability to directly correlate fatty acid profiles to intact lipid molecules. To address this issue, we present a workflow to determine FA profiles from lipidomics data sets termed LC-MS fatty acid data extraction (LC-MS FADE). FA data were extrapolated from intact lipid peak areas and expressed as percent fractions. A total of eight disparate lipid extracts, including fetal bovine serum, nutritional yeast, beef liver, canola oil, Viral Producing Cells 1.0, Arabidopsis thaliana, Acheta domesticus, and Escherichia coli K12 were analyzed to assess the accuracy of this strategy. By comparing the LC-MS FADE profile to the GC-MS FAME profile, an average R2 value of 0.89 was obtained, demonstrating that LC-MS FADE can successfully and accurately extract FA profiles. LC-MS FADE data sets displayed improved detectivity by identifying more FAs with improved reproducibility compared to GC-MS FAME data. Significantly, lipid class-specific FA insights were obtained using LC-MS FADE that were not accessible with traditional GC-MS methods. LC-MS FADE can also be applied retrospectively to existing lipidomics data sets, enabling extraction of FA profiles from data not originally intended for FA analysis. This method provides additional insight into FA dynamics in complex untargeted lipidomics data sets and can be readily implemented into lipidomic workflows.
    DOI:  https://doi.org/10.1021/acs.analchem.6c01325
  20. Analyst. 2026 Jul 07.
    Analytical challenges in mapping the subcellular metabolome and lipidome.
    Marta Nobile, Simone Serrao, Eleonora Bossi, Francesca Re, Francesca Raimondo, Giuseppe Paglia.
      Mass spectrometry-based metabolomics and lipidomics are central analytical tools for characterizing cellular chemical composition. However, most workflows still rely on the simplifying assumption of homogeneous intracellular pools, which is increasingly inadequate for spatially organized eukaryotic systems. Metabolites and lipids are distributed across subcellular compartments that differ in chemical environment, turnover, and accessibility, thereby affecting both measurement and interpretation. Recent advances in subcellular and spatial metabolomics have highlighted both the potential and the limitations of organelle-resolved analysis, particularly in terms of extraction chemistry, quantification, and data interpretation. In this review, we critically examine organelle-resolved metabolomics and lipidomics from a mass spectrometry-centric perspective, treating subcellular compartmentalization as an analytical variable rather than solely a biological feature. By comparing metabolomics and lipidomics studies on subcellular compartments, we evaluate fractionation-based, affinity-based, and spatial MS strategies, and we highlight current capabilities, common artefacts, and future opportunities, including the integration of stable isotope tracing and emerging single-organelle approaches such as Nanoscale Secondary Ion Mass Spectrometry (NanoSIMS) and Direct Organelle Mass Spectrometry (DOMS).
    DOI:  https://doi.org/10.1039/d6an00535g
  21. Anal Chem. 2026 Jul 04.
    Development of a Tapping-Mode Scanning Probe Electrospray Ionization Platform for High-Sensitivity and Long-Term Stability in Single-Cell Mass Spectrometry Imaging of Tissue.
    Takao Yasuda, Yoichi Otsuka, Tasuku Kato, Shuichi Shimma, Tomoki Misaka, Takuya Matsumoto, Michisato Toyoda.
      To elucidate disease mechanisms, it is essential to develop analytical techniques capable of visualizing cellular heterogeneity in biological tissues. Mass spectrometry imaging (MSI) allows simultaneous visualization of multiple biomolecules in tissue sections in a single measurement. However, achieving single-cell (SC)-MSI requires high ion detection sensitivity and long-term ionization stability. Tapping-mode scanning probe electrospray ionization (t-SPESI) delivers a tiny amount of solvent from an oscillating fused silica capillary probe to the sample surface, enabling rapid extraction and ionization of analytes. In this study, we developed a t-SPESI measurement system and a chemical modification method for the probe surface to enable SC-MSI of biological tissues. Introducing a compact sample stage shortened the ion transfer tube to the mass spectrometer, thereby increasing ion detection sensitivity. Furthermore, forming a fluorine-containing molecular layer on the probe surface suppressed biomolecule adsorption at the probe tip and increased the long-term stability of solvent delivery. SC-MSI of mouse brain sections was performed at pixel sizes of 10 and 5 μm and visualized lipid distributions corresponding to fine tissue structures. These results demonstrate that the combination of system miniaturization and probe surface modification is an effective strategy for achieving high-sensitivity and long-term stable SC-MSI via t-SPESI, providing a robust platform for investigating cellular heterogeneity in biological tissues.
    DOI:  https://doi.org/10.1021/acs.analchem.6c02386
  22. Crit Rev Anal Chem. 2026 Jul 08. 1-30
    Matrix Effects and Analytical Instability in Pharmaceutical Bioanalysis: Current Challenges and Future Directions.
    Hemn A H Barzani, Rebaz Anwar Omer, Nergz Bayiz Abdulrahman, Hunar Yasin Muhammad, Ali Sedeeq Noaman, Kovan Dilawer Issa, Seerwan Hamadameen Sulaiman.
      Pharmaceutical bioanalysis plays a central role in drug development, therapeutic drug monitoring, pharmacokinetics, metabolomics, and clinical diagnostics; however, the increasing complexity of biological and pharmaceutical matrices has created major analytical challenges related to matrix effects and analyte instability. Endogenous compounds such as phospholipids, proteins, salts, metabolites, and formulation excipients can interfere with chromatographic separation and electrospray ionization, leading to ion suppression or enhancement, signal fluctuations, reduced sensitivity, and compromised quantitative accuracy. In addition, hydrolysis, oxidation, photodegradation, enzymatic degradation, and adsorption processes can significantly affect analyte stability during sample collection, storage, preparation, and LC-MS analysis. This review critically evaluates the mechanistic basis of matrix effects and analytical instability in pharmaceutical bioanalysis and highlights recent advances in intelligent analytical technologies designed to improve analytical robustness, reproducibility, and sustainability. Advanced sample preparation strategies, including selective SPE, phospholipid-removal systems, MIP, and microextraction technologies, together with modern LC-MS platforms such as UHPLC-MS/MS and HRMS, have significantly enhanced trace-level pharmaceutical analysis in complex matrices. Furthermore, artificial intelligence-assisted workflows, microfluidics, biosensors, and omics-based analytical systems are transforming pharmaceutical bioanalysis toward automated and smart analytical ecosystems. Future pharmaceutical bioanalysis is expected to integrate intelligent, sustainable, and highly automated analytical systems that combine AI-driven analytics, advanced LC-MS technologies, green and white analytical chemistry principles, and harmonized regulatory frameworks to improve clinical applicability, analytical reliability, and environmental sustainability.
    Keywords:  Artificial intelligence in analytical chemistry; LC–MS/MS; analytical instability; matrix effects; pharmaceutical bioanalysis
    DOI:  https://doi.org/10.1080/10408347.2026.2698067
  23. Angew Chem Int Ed Engl. 2026 Jul 08. e4492989
    Beyond the Fixed Charge: A New On-Tissue Derivatisation Strategy Employing Photoionisable Chromophores for Mass Spectrometry Imaging of Amino-Containing Metabolites.
    Sofia R McGowan, Andrew J Tague, Ashna A Kumar, Marie Ranson, Christopher J T Hyland, Shane R Ellis.
      Matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI) has been widely adopted for the spatially resolved mapping of chemical composition within biological tissues. However, inherent limitations in ionisation efficiencies limit the scope of analyte detection. Currently, methods to enhance molecular coverage have focused on chemical derivatisation of target analyte classes or post-ionisation techniques, namely, laser post-ionisation (MALDI-2). Previously, we observed that under reduced laser fluence conditions, MALDI-2 can be utilised to selectively enhance photoionisation of aromatic analytes. Leveraging these observations, we have conducted a proof-of-concept study to establish a conceptually novel class of derivatisation reagents, employing a tocopherol active chromophore O-linked succinimide (TAC/OS) for the selective derivatisation of primary amines. Using TAC/OS, amino metabolites were selectively detected as the derivatised radical cations in the presence of MALDI-2. Across three tissue types, over 30 metabolites were detected and localised, including 20 amino acids alongside neurotransmitters such as γ-aminobutyric acid (GABA) and dopamine. Imaging at 10 µm pixel size revealed minimal delocalisation, allowing for MSI at near single-cell resolution. Furthermore, we demonstrated the ability of the developed protocol on late-stage pancreatic cancer xenografts.
    Keywords:  chemical derivatization; chromophores; laser post‐ionization; mass spectrometry imaging; spatial metabolomics
    DOI:  https://doi.org/10.1002/anie.4492989
  24. Anal Bioanal Chem. 2026 Jul 10.
    Tandem column coupling in supercritical fluid chromatography-mass spectrometry for the multiresidue analysis of pesticides in complex Allium vegetables.
    Víctor Cutillas, Alba Cano, María Jesús Martínez-Bueno, Amadeo R Fernández-Alba.
      Supercritical fluid chromatography coupled with tandem mass spectrometry (SFC-MS/MS) has established itself as a powerful, environmentally sustainable alternative to conventional liquid chromatography for the multiresidue analysis of pesticides in food matrices. While single-column SFC-MS/MS configurations based on C18 stationary phases have demonstrated clear analytical advantages, their performance can be severely compromised in difficult matrices such as Allium vegetables, where dense co-extractive backgrounds cause significant ion suppression and limit method sensitivity. The serial coupling of columns with complementary selectivities is an inherently SFC-compatible strategy to improve chromatographic resolution without the pressure constraints that restrict analogous approaches in liquid chromatography. In this study, two tandem column configurations were evaluated for the SFC-MS/MS determination of 216 pesticides in onion, leek, and garlic: a 15 cm Silica column coupled upstream to a 25 cm C18 column, and a 15 cm Fluorophenyl column coupled to the same C18 column. Method performance was assessed by comparing limits of quantification (LOQ), matrix effects (ME), and reproducibility (RSD) against a reference single-C18 configuration across the three matrices. The assessment of method performance revealed that both tandem configurations effectively mitigated matrix effects relative to the single C18 setup, though with distinct trade-offs. The Fluorophenyl + C18 coupling provided a meaningful reduction in signal suppression across all matrices but this came at the cost of deteriorated reproducibility and a compound-dependent effect on sensitivity (in garlic it improved the LOQ of 27 compounds while worsening 23). Conversely, the Silica + C18 configuration proved to be the most balanced and robust strategy. It dramatically improved matrix effect mitigation (up to 78.7% of compounds showing negligible effects in onion), lowered LOQs for 38 compounds in garlic, and successfully preserved method precision by reducing the fraction of compounds with highly variable RSDs (> 20%) from 7.4% to just 1.4% in garlic. Finally, this Silica + C18 configuration was utilized for the analysis of real vegetable samples.
    Keywords:  Multiresidue analysis; Orthogonal stationary phases; Pesticides; Supercritical Fluid chromatography (SFC); Tandem columns
    DOI:  https://doi.org/10.1007/s00216-026-06662-4
  25. J Environ Sci Health A Tox Hazard Subst Environ Eng. 2026 Jul 07. 1-16
    HPLC-MS method for tracing multiclass PPCPs in soil and water: optimization of ionization and extraction strategies.
    Dileep Singh, Smriti Gupta, Thomas Boving, Bhanu Prakash Vellanki.
      A high-performance liquid chromatography-mass spectrometry (HPLC-MS) method was developed for the determination of 27 multiclass pharmaceuticals and personal care products (PPCPs) in soils and 30 PPCPs in surface water and groundwater using atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI). Conventional PPCP methods often suffer from limited analyte coverage and pronounced matrix effects, particularly in soils, challenges that are further exacerbated in conventional single-quadrupole HPLC-MS systems compared to MS/MS platforms that are not readily accessible in many developing regions. To address these challenges, the method targeted diverse compound classes, including antibiotics, analgesics, non-steroidal anti-inflammatory drugs, β-blockers, lipid regulators, estrogens, and other emerging contaminants, supported by systematic optimization of extraction and ionization conditions. A single extraction protocol enabled simultaneous analysis of 27 PPCPs in soils with APCI providing broader analyte coverage and reduced matrix effects compared to ESI. Median quantification limits were 1.5 ng g-1 for soils, 17.2 ng L-1 for surface water, and 5.8 ng L-1 for groundwater. Application to samples from the Yamuna River Basin (Delhi, India) revealed at least 15 PPCPs across all matrices. The study demonstrates that optimized single-quadrupole HPLC-MS provides a sensitive and accessible approach for routine multiclass PPCP monitoring.
    Keywords:  APCI; HPLC-MS; PPCPs; matrix effects; solid phase extraction; ultrasonic extraction
    DOI:  https://doi.org/10.1080/10934529.2026.2695547
  26. Talanta. 2026 Jun 30. pii: S0039-9140(26)00889-1. [Epub ahead of print]311 130233
    Enhanced determination of 85 mycotoxins in challenging root and rhizome herbal medicines using online segmented multi-dimensional liquid chromatography-tandem mass spectrometry.
    Huiqin Pan, Jing Xu, Xiaoya Qin, Yannan Tan, Ling Chen, Rui Feng, Yimin Cao, Suyun Chen, Shen Ji, Qing Hu, Heng Zhou.
      Sensitive and accurate detection of mycotoxin contaminations is crucial for ensuring safety of herbal medicines. However, their inherent chemical complexity poses significant challenges for reliable method development. Herein, an innovative segmented multi-dimensional liquid chromatography-tandem mass spectrometry (sMD-LC-MS/MS) method was developed for detection of 85 mycotoxins in complex root and rhizome herbs. By integrating multiple heart-cutting, segmented trapping, and dual-mode second-dimension separations, it resolved critical co-elution issues from conventional 1D analysis. Coupled with a simple "dilute-and-shoot" workflow, the system eliminated offline purification, enhancing throughput. Method validation across six representative herbal matrices demonstrated that this "panoramic" strategy significantly outperformed conventional LC-MS/MS method and achieved improvements in qualitative reliability, quantitative accuracy, and detection sensitivity. It provided a systematic solution for high-throughput, highly reliable detection of trace-level, multiclass mycotoxins in challenging herbal matrices.
    Keywords:  Multi-mycotoxins; Online segmented multi-dimensional LC-MS/MS; Root and rhizome herbal medicine; Screening and quantification
    DOI:  https://doi.org/10.1016/j.talanta.2026.130233
  27. J Am Soc Mass Spectrom. 2026 Jul 10.
    An m/z- and Intensity-Based HRMS Clustering Algorithm Targeted toward Single-Cell Metabolomics.
    Dirk Wevers, Laura Koldenhof, Laura Castaneda, Anouschka van der Zeeuw, Hellen Fass, Thomas Hankemeier, Charlie Clark, Ahmed Ali.
      Single-cell (SC) metabolomics holds great potential in the development of novel diagnostic tools and mechanistic insights into cell biology. Using high-resolution mass spectrometry (HRMS), the masses of a single cell's constituents can be determined with an accuracy high enough to derive their respective elemental compositions. Using a molecule's mass and its MS fragmentation pattern, in many cases a molecular structure can be assigned or looked up in databases. Due to the small measurement cell volume of an Orbitrap HRMS instrument, samples need to be scanned multiple times, which necessitates across-scan clustering per sample, and across-sample alignment of m/z values. However, existing HRMS data processing software is not designed to process SC HRMS data, as it typically requires liquid chromatography retention times or reference spectra for m/z clustering and alignment. Herein, a novel, robust SC HRMS m/z clustering and alignment algorithm is presented and compared with two commercially available and industry standard algorithms used by Sciex MarkerView and Thermo FreeStyle. Furthermore, output is compared with clustering results from DBSCAN and MaldiQuant binning. Our algorithm, Global Clustering unTargeted Analysis (GCTA), enforces a strict maximum on the cluster size, thereby reducing the chance of peak aggregation. Furthermore, by design, GCTA enables noise filtering based on intensity and number of peaks. Across-scan clustering and across-sample alignment were contrasted for accuracy in finding peaks identified by commercial software output and peaks with known m/z values corresponding to standards and HMDB and LipidMaps database hits. Comparisons are made based on data recorded for quality control samples containing standard mixes as well as SC HRMS data recorded for two different cell lines. This work shows that the presented algorithm is comparable in accuracy with respect to MarkerView and FreeStyle, reliably identifies compounds, is less prone to peak splitting than MaldiQuant binning while providing similar levels of error in clustering peaks, and successfully filters noise. Furthermore, it is shown to be competitive with DBSCAN, MaldiQuant binning and MarkerView when compared to theoretical m/z values based on database hits. GCTA encompasses both m/z clustering and reference-free alignment, which makes it pivotal to further development of untargeted SC HRMS metabolomics.
    Keywords:  HRMS data processing; aggregation; noise filtering; peak splitting; reference-free clustering and alignment; single-cell metabolomics
    DOI:  https://doi.org/10.1021/jasms.6c00150
  28. Appl Spectrosc. 2026 Jul 07. 37028261470406
    EXPRESS: Precursor/Fragment Ion Identification from Bulk Analysis of a Mixture through Two-Dimensional Correlation Mass Spectrometry.
    Elly A Breves, Garon H Lowke, Jacob T Shelley.
      The identification of analytes in complex mixtures with mass spectrometry (MS) is often complicated by isobaric overlap, adduct/fragment formation, isotopic distributions, and competitive ionization. Common analysis methods such as chromatography-coupled MS and tandem-MS require physical separation or isolation of analytes prior to mass analysis. This work demonstrates that two-dimensional correlation techniques, used widely in optical spectroscopy, can be adapted to MS to identify precursor and fragment ion pairs from the direct analysis of a two-component mixture, obviating the need for sequential separation or isolation of analytes. A mathematical framework is presented to threshold correlation-derived metrics to predict whether two mass-spectral signals arose from the same molecular origin. Single-analyte spectra derived from the time-averaged mass spectrum of the mixture with these metrics were identified through the National Institute of Standards and Technology (NIST) MS Search 2.2 software with greater than 90% accuracy. Though presented here for data acquired with direct analysis in real time (DART) mass spectrometry, these methods can be directly applied to other mass-spectral datasets that have a time-dependent signal, including metabolomics, petroleomics, natural organic matter, forensics, and chemical reaction monitoring.
    Keywords:  2D-COS; correlation analysis; cross-correlation; mass spectrometry
    DOI:  https://doi.org/10.1177/00037028261470406
  29. Int J Mass Spectrom. 2025 Feb;508 117386
    Development of an optimised method for the analysis of human blood plasma samples by atmospheric solids analysis probe mass spectrometry.
    Oxford Acute Myocardial Infarction (OxAMI) Studyoxami@cardiov.ox.ac.uk
      Analysis of small-molecule metabolites in plasma has the potential for development as a clinical diagnostic and prognostic tool. Atmospheric solids analysis probe mass spectrometry (ASAP-MS) is capable of performing rapid metabolite and small molecule fingerprinting, and has the potential for use in a clinical setting. Combining ASAP-MS data with a predictive model could provide clinicians with a rapid patient risk metric, anticipating disease progression and response to treatment, and thereby aiding in treatment decisions. In order to develop predictive models, experimental errors and uncertainties must be minimised, requiring a robust experimental protocol. In the present study we have performed ASAP-MS measurements on plasma samples from patients recruited for two prospective clinical studies: the Oxford Acute Myocardial Infarction (OxAMI) study; and the Oxford Abdominal Aortic Aneurysm (OxAAA) study. Through a carefully designed series of measurements, we have optimised the method of sample introduction, together with a number of key instrument and data acquisition parameters. Following the optimisation process, we are consistently able to record high quality mass spectra for plasma samples. Typical coefficients of variation for individual mass peaks are in the range from 20%-50%, overlapping with those obtained using more sophisticated LC-MS approaches. The measurement protocol optimises mass spectral quality and reproducibility, while retaining the simplicity of measurement required for use in a clinical setting. While the protocol was developed using plasma samples from two specific patient cohorts, the method can be generalised to any plasma measurements.
    Keywords:  Atmospheric solids analysis probe mass spectrometry; Metabolite profile; Plasma; Protocol optimisation
    DOI:  https://doi.org/10.1016/j.ijms.2024.117386
  30. Anal Chim Acta. 2026 09 22. pii: S0003-2670(26)00707-5. [Epub ahead of print]1416 345757
    Hybridization LC-MS/MS: An alternative platform to enable specific and sensitive quantification of Antibody-ASO conjugates.
    Guilherme J Guimaraes, Ting Jiang, Bekim Bajrami, Long Yuan.
      Antibody-antisense oligonucleotide (Ab-ASO) conjugates are an innovative class of therapeutics that merge the gene-modulation capabilities of ASOs with the tissue-targeting properties of monoclonal antibodies. Sensitive, selective, and reliable methods to quantify Ab-ASO conjugates in biological samples are critical to understand their pharmacokinetics, pharmacodynamics, toxicity, and biodistribution properties. While ligand-binding assay (LBA) approach is common, it is often limited by the need for multiple custom reagents and narrower dynamic range. In this work, we present a robust hybridization LC-MS/MS strategy for the quantitation of Ab-ASO conjugates using sequence-specific hybridization extraction. Discovery proteomics was utilized to identify and select high-specificity surrogate peptides for the antibody moiety. The method leverages a biotinylated complementary DNA probe to selectively enrich the conjugate through Watson-Crick base pairing, followed by tryptic digestion and LC-MS/MS quantitation of surrogate peptides. The assay was successfully qualified in mouse serum over the range of 10.0 - 10,000 ng/mL and applied to a single-dose pharmacokinetic study, demonstrating high analytical agreement with a benchmark LBA strategy. The LC-MS/MS approach provides a superior dynamic range, simplifies reagent requirements and offers an LC-MS based quantitation platform that was previously unavailable for Ab-ASO conjugate quantitation.
    Keywords:  Antibody-ASO conjugates; Antibody-oligonucleotide conjugates (AOCs); Hybridization LC-MS/MS; Hybridization extraction; Surrogate peptide quantitation
    DOI:  https://doi.org/10.1016/j.aca.2026.345757
  31. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2026 Jul 06. 1-18
    High-throughput multi-residue determination of 157 pesticides in wine using QuEChERS-UPLC-MS/MS for routine monitoring applications.
    Artemis P Louppis, Michalis S Constantinou.
      A rapid and reliable multi-residue analytical method was developed for the simultaneous determination of 157 pesticide residues in wine using QuEChERS extraction followed by ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The extraction protocol included two extract-treatment pathways to enable the determination of acidic pesticides as well as compounds with different stability under acidic or basic conditions. The method was validated according to the SANTE guidelines for pesticide residue analysis. Matrix-matched calibration curves showed good linearity for all analytes, with correlation coefficients (R2) ranging from 0.9866 to 0.9994 within the concentration range of 0.005-0.080 mg kg-1 and the limits of detection (LOD) and quantification (LOQ) were established at 0.0033 mg kg-1and 0.010 mg kg-1, respectively. Recovery values ranged from 72 to 116%, while repeatability (RSDr) and within-laboratory reproducibility (RSDR) were ≤15.2% and ≤19.7%, respectively. Expanded measurement uncertainty ranged from 5 to 42% (k = 2). The validated method was applied to commercial wine samples, where several pesticide residues were detected at concentrations between 0.0082 and 0.1881 mg kg-1. The developed method demonstrated high suitability for high-throughput routine monitoring and large-scale surveillance of pesticide residues in wine due to its sensitivity, accuracy and rapid analysis time.
    Keywords:  Multi-residue pesticides; QuEChERS extraction; UPLC-MS/MS; pesticide residue monitoring; wine analysis
    DOI:  https://doi.org/10.1080/19440049.2026.2697494
  32. J Anal Toxicol. 2026 Jul 08. pii: bkag060. [Epub ahead of print]
    Paper Spray Mass Spectrometry for Rapid Toxicology Targeted Screening of Emergency Department Samples: A Research Study.
    Stefania Boccuzzi, David Cowan, Paul I Dargan, Edward Goucher, Vincenzo Abbate.
      Acute recreational drug toxicity (ARDT) is a frequent cause of emergency department (ED) presentations, yet comprehensive toxicological testing by chromatographic techniques is rarely conducted due to limited availability and resource-intensive workflows. Consequently, initial clinical decisions are made without analytical confirmation. Paper spray-mass spectrometry (PS-MS) may offer an alternative approach for targeted clinical toxicology screening owing to its rapid and simplified analysis of biological samples. Serum donor samples from patients presenting to the ED with suspected ARDT were analysed using PS-MS and liquid chromatography-tandem mass spectrometry (LC-MS/MS) for method comparison. Targeted screening and quantitative performance were evaluated using pooled diagnostic metrics, orthogonal regression, per-analyte % bias and Bland-Altman analyses. PS-MS was subsequently applied to a larger screening-only cohort to assess analytical performance, detection frequency, and concentration distributions across a clinically relevant drug panel. Across 114 research samples, PS-MS demonstrated high targeted screening performance, with a pooled sensitivity of 82.7%, specificity and positive predictive value of 100%, and negative predictive value of 98.2%. Quantitative comparison showed strong correlation between methods, with proportional bias at higher concentrations and no single analyte influencing the agreement metrics. In the screening-only cohort (n = 99), PS-MS detected and quantified a broad range of analytes, including evidence of polydrug use. Several low-frequency analytes were not observed within the analysed serum donor sample cohort. PS-MS may provide a fast and specific targeted screening approach for ARDT in ED samples, delivering analytically informative toxicological data. While not a replacement for confirmatory testing or a validated in vitro diagnostic assay, this research study into PS-MS represents a valuable complementary tool to support downstream confirmatory testing.
    Keywords:  acute recreational drug toxicity; clinical toxicology; emergency department; paper spray mass spectrometry; targeted drug screening
    DOI:  https://doi.org/10.1093/jat/bkag060
  33. J Sep Sci. 2026 Jul;49(7): e70488
    Determination of Pyrrolizidine Alkaloids and Their N‑Oxides in Bee Pollen by Accelerated Solvent Extraction Followed by Magnetic Covalent Organic Framework-Based Offline Purification and Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry.
    Yuhang Wang, Yujia Guo, Guoda Wang, Xiao Feng, Mingrong Qian, Zuguang Li.
      Pyrrolizidine alkaloids (PAs) and their N-oxides (PANOs) are naturally occurring toxic plant metabolites that have attracted widespread attention due to their potential food safety hazards. In this study, an efficient analytical method for determining PAs/PANOs in bee pollen was established by combining accelerated solvent extraction (ASE) with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). A magnetic covalent organic framework material (Fe3O4@COF-TAPB-TFP) was synthesized and used as an adsorbent for offline purification to reduce matrix interference and improve detection sensitivity. Under optimal conditions, the method showed excellent linearity (R2 ≥ 0.99) in the range of 1-200 µg·L- 1, with recoveries of 70.1%-95.6% for spiked blank samples at three levels (10, 50, and 100 µg·kg- 1), relative standard deviations below 15%, and limits of quantification of 1.2-9.9 µg·kg- 1. This method was successfully applied to the analysis of local market bee pollen samples, with detected PAs/PANOs levels ranging from 25.6 to 178.6 µg·kg- 1. Overall, the Fe3O4@COF-TAPB-TP-assisted ASE-UHPLC-MS/MS method provides an accurate, rapid, highly automated, and high-throughput platform for monitoring PAs/PANOs contamination in food products.
    Keywords:  UHPLC‐MS/MS; accelerated solvent extraction; bee pollen; pyrrolizidine alkaloids
    DOI:  https://doi.org/10.1002/jssc.70488
  34. Shokuhin Eiseigaku Zasshi. 2026 ;67(3): 126-132
    [Validation Study on a Rapid Method for Simultaneous Determination of Pesticide Residues in Livestock Products by LC-MS/MS].
    Makiko Tonohara, Yurika Awano, Akio Itoh, Masumi Waki.
      A simultaneous rapid test method for pesticide residues in livestock products by LC-MS/MS was developed and validation tests were conducted. For the extraction method, the QuEChERS method was applied, and samples were extracted with acetonitrile, followed by salting out and dehydration. For purification, C18 and PSA columns were used instead of GPC. Based on the validity guidelines of the Ministry of Health, Labor and Welfare, 48 pesticide residues were evaluated at 0.01 μg/g and 0.1 μg/g for cattle muscle, swine muscle and milk. The trueness of the method for 43 pesticides in all three types of food samples was 70-120%, with satisfactory repeatability and within-laboratory reproducibility. Thus, this method demonstrated the usefulness of simultaneous rapid testing for pesticide residues in livestock products.
    Keywords:  Liquid chromatography/tandem mass spectrometry (LC-MS/MS); livestock products; method validation; pesticide residue; simultaneous determination
    DOI:  https://doi.org/10.3358/shokueishi.67.126
  35. Se Pu. 2026 Jul;44(7): 806-811
    [Simultaneous determination of glycerol， acetic acid， and sodium bisulfite in compound amino acid injection （14AA） using ion exclusion chromatography].
    Yong-Sheng Gu, Li-Min Zuo, Xiao-Li Gao, Guang-Zhi Shan, Jun Zhao.
      An ion exclusion chromatography method was established for the simultaneous determination of glycerol， acetic acid and sodium bisulfite in compound amino acid injection （14AA）. No tedious sample pretreatment is required； the sample can be directly injected after filtration through a 0.22 μm membrane filter. Chromatographic separation was achieved using an Xtimate Sugar-H column （300 mm×7.8 mm， 5 μm） packed with a strong ion-exchange resin based on a rigid styrene/divinylbenzene matrix， which is specially designed for the separation of sugar alcohols and organic acids via the ion-exclusion mechanism. The mobile phase was 7.5 mmol/L sulfuric acid solution， which was selected as it can suppress the ionization of target analytes and enhance their retention on the stationary phase； the amino groups of amino acid components undergo strong ionization， leading to no retention. Isocratic elution was adopted to ensure stable separation efficiency and short analysis time， with the flow rate set at 0.5 mL/min. Based on the ultraviolet absorption characteristics of the target analytes， 200 nm was selected as the detection wavelength. The column temperature was set at 65 ℃ and the injection volume was optimized to 10 μL， which ensures the detection sensitivity while avoiding column overload. The external standard method was adopted for quantitative analysis， featuring simple operation and reliable results. The method exhibited excellent specificity： blank solvent and negative matrix solution tests verified that amino acids caused no interference with the determination of target analytes， and the target analytes achieved good resolution from adjacent peaks. For the linearity investigation， standard solutions were prepared with linear ranges set as follows： 1.197-59.87 mg/mL for glycerol， 0.036 08-1.804 mg/mL for acetic acid， and 0.000 791 6-0.633 3 mg/mL for sulfite. Within these mass concentration ranges， the linear correlation coefficients （r） of all components were greater than 0.999 5， indicating an excellent linear relationship of the method. The accuracy was verified by spiked recovery tests at three levels （80%， 100% and 120% of the labeled amount）， with three parallel preparations for each level. The results showed that the average recoveries of the target analytes ranged from 99.21% to 102.6%， with relative standard deviations （RSDs） of 0.09% to 0.86% （n=3）， demonstrating the high accuracy of this method. The ion exclusion chromatography method established in this study can effectively eliminate the interference of the amino acid matrix in compound amino acid injection （14AA）， and has the advantages of rapid analysis， simple operation， strong specificity and high accuracy， making it suitable for the routine quality control of glycerol， acetic acid and sodium bisulfite in this preparation. This method provides a reliable analytical and testing tool for the quality assurance and safety control of compound amino acid injection （14AA） during production and storage.
    Keywords:  acetic acid; compound amino acid injection （14AA）; glycerol; ion exclusion chromatography; sodium bisulfite
    DOI:  https://doi.org/10.3724/SP.J.1123.2026.01005
  36. Shokuhin Eiseigaku Zasshi. 2026 ;67(3): 109-113
    [Surveillance of the Levels of Naturally Derived Benzoic Acid in Fresh Foods ②Examination of Qualitative and Quantitative Improvements Using Citrus Fruits in the Dialysis Method].
    Rio Suzuki, Yu Shiozawa, Shui Watanabe, Ayako Ito, Itoko Baba, Yukiko Yamajima, Toshiko Shimoi, Narue Sakamaki, Kenji Otsuka, Maki Kanda.
      In analyzing the content of naturally derived benzoic acid (BA) using the dialysis method, we optimized the analytical conditions to enhance both qualitative and quantitative capabilities. The dialysis method does not involve heating operations, so it reflects the actual content of BA without the influence of such as hydrolysis. However, in LC analysis, components derived from food affect the qualitative and quantitative analysis of BA. Therefore, in this study, we examined the selection of LC columns and detectors for 36 citrus samples, which are significantly affected by interference. As a result, using the Phenyl-Hexyl column in LC-PDA measurement allowed for result determination without interference in 7 samples. For the remaining 29 samples, it was possible to determine the presence of BA using LC-MS/MS measurement with improved selectivity. One orange sample was quantified using the standard addition method to correct for matrix effects and calculate the BA content.
    Keywords:  LC-MS/MS; benzoic acid; citrus fruits; dialysis; phenyl-hexyl column; standard addition method
    DOI:  https://doi.org/10.3358/shokueishi.67.109
  37. Anal Chem. 2026 Jul 06.
    Comprehensive Isomer-Resolved Ganglioside Profiling by HILIC-nanoESI-MS/MS.
    Nina Troppmair, Jonas Santol, Mark Baumert, Lukáš Opálka, Alice Assinger, Cristina Coman, Robert Ahrends.
      Gangliosides are structurally complex glycosphingolipids that regulate cellular signaling via interactions with extracellular binding partners and by influencing protein function within the membrane. Their comprehensive analysis remains analytically challenging, in part due to low endogenous abundance, extensive structural diversity, and the frequent occurrence of isomeric species arising from both glycan and ceramide moieties. Here, we present a hydrophilic interaction liquid chromatography (HILIC) nanoelectrospray ionization tandem mass spectrometry (nanoESI-MS/MS) method specifically designed to achieve isomer-resolved analysis and molecular species-level quantification of gangliosides. To improve characterization of low-abundance fatty acyl fragments, the workflow was extended by combining nanoESI with online fraction collection and subsequent direct infusion. The method demonstrated stable chromatographic performance, high sensitivity, and reproducible quantitative results across ten mouse tissues. Application of the workflow enabled quantification of 80 ganglioside molecular species belonging to 18 subclasses and revealed pronounced tissue-specific differences in subclass distribution and ceramide composition. Overall, this study establishes a robust and sensitive platform for comprehensive ganglioside analysis, providing new opportunities to investigate ganglioside diversity, regulation, and function in complex biological systems.
    DOI:  https://doi.org/10.1021/acs.analchem.6c00380
  38. Anal Chim Acta. 2026 09 22. pii: S0003-2670(26)00708-7. [Epub ahead of print]1416 345758
    Hybrid dissociation modes in a portable ion trap mass spectrometer for enhanced specificity in complex mixture analysis.
    Jun Zhan, La Chen, Gangqiang Li, Luhong Wen.
      Direct ionization ion trap mass spectrometry (ITMS) consistently faces challenges from matrix interference, necessitating highly specific analytical strategies to ensure reliable compound identification. However, the performance of tandem mass spectrometry (MS/MS) in conventional ITMS systems, which primarily rely on collision-induced dissociation (CID) for ion activation-is often constrained by the low-mass cutoff (LMCO) effect and suboptimal fragmentation efficiency. To address these limitations, we developed a portable ITMS platform that integrates both beam-type collision-induced dissociation (bCID) and CID technologies. In this platform, a flared ion guide serves dual roles as an ion transfer device and a collision cell for bCID. Compared with a parallel square-rod ion guide, the flared design-without compromising instrument portability shortens the dissociation time from 40 to 20 ms and increases the total dissociation efficiency by approximately 10%. Experimental results demonstrated that the bCID activation method effectively alleviates the LMCO restriction, while simultaneously improving fragmentation efficiency and analytical throughput, particularly for low-mass fragments. Furthermore, bCID provides greater flexibility in modulating fragment ion abundance through dissociation voltage adjustment and exhibits a distinct advantage in dissociating molecules containing strong chemical bonds. In the analysis of complex matrices such as hair and serum, bCID enhanced the signal-to-noise (S/N) ratios for compounds including tramadol, metonitazene and brodifacoum compared to CID. This enhancement was achieved by strengthening low-mass fragment ion intensities while reducing background noise through the breakdown of matrix-derived interference ions into non-specific fragments. Additionally, the complementary use of CID and bCID offered superior specificity for detecting designer drugs (e.g., etomidate and propoxate) in urine and food additives (e.g., saccharin sodium and benzoic acid) in ham, by generating a sufficient set of diagnostic ions with high abundance and S/N ratios. These findings underscore the importance of incorporating the hybrid dissociation modes into portable ITMS systems for on-site analysis of complex samples.
    Keywords:  Direct ionization; Hybrid dissociation modes; Low-mass cutoff effect; Portable ion trap mass spectrometer; Tandem mass spectrometry
    DOI:  https://doi.org/10.1016/j.aca.2026.345758
  39. J Proteome Res. 2026 Jul 10.
    Reverse Biotransformation-Guided Annotation of Untargeted MS/MS Features: A Computational Framework for Candidate Enzyme and Gene Hypothesis Generation.
    Smaroki Smruti Rekha, Palok Aich.
      Untargeted LC-MS/MS experiments detect thousands of metabolic features, yet most remain unannotated due to limited spectral and structural database coverage. To address this limitation, we present a modular workflow that identifies closest structural analogs from MS/MS-derived features, applies rule-based reverse biotransformation to infer plausible precursor reactions, and maps these reactions to candidate enzymes and genes. Confidence-aware parameter selection and rule scoring are incorporated to balance annotation coverage with biological plausibility. Evaluation on reference data sets using systematic sensitivity analyses justified analog retrieval and biotransformation confidence thresholds. Pipeline-derived gene sets consistently recapitulated pathways reported in prior metabolite-gene association studies and exhibited stronger pathway enrichment than baseline associations. Application to independent experimental metabolite lists produced biologically coherent pathway enrichments across heterogeneous data sets. For a lesser-characterized metabolite, inferred genes were highly enriched in glutathione metabolism and oxidative stress pathways (adjusted p < 2 × 10-4). This confidence-aware integration of spectral annotation and reverse biotransformation provides a reproducible and interpretable framework for generating candidate enzyme and gene hypotheses from poorly annotated MS/MS features, enhancing the biological interpretation of metabolomics-driven discovery.
    Keywords:  MS/MS spectral annotation; enzyme-gene mapping; pathway enrichment; reverse biotransformation; untargeted metabolomics
    DOI:  https://doi.org/10.1021/acs.jproteome.6c00138
  40. Appl Spectrosc. 2026 Jul 07. 37028261450236
    EXPRESS: Identification of Unknown Peaks in Mass Spectra Based on the Characteristic Isotopic Pattern via the Hilbert-Noda Matrix.
    Ying Liu, Lei Gao, Anqi He, Honggang Nie, Limin Yang, Yukihiro Ozaki, Isao Noda, Yizhuang Xu.
      Mass spectrometry (MS) is a powerful chemical analysis technique and one of the leading approaches that allows the identification and quantification of thousands of different components via a highly sensitive manner. However, assignment of unknown peaks in a mass spectrum to specific fragments is still a labour-intensive and costly task. Although various approaches and numerous software platforms have been developed, the automatic assignment of unknown peaks remains an unsolved problem. Based on the self-orthogonality of the Hilbert-Noda matrix extensively used in the field of 2D correlation spectroscopy, we develop a new method to generate an auxiliary spectrum to highlight peaks for the fragments containing stable isotopes via the characteristic pattern of the peaks for the isotopologues in the mass spectra. To address the problem of coincidental orthogonality, a modified approach using the second-order Hilbert-Noda matrix is proposed. Moreover, a statistical approach is adopted to suppress the appearance of false-positively highlighted peaks in the auxiliary spectra. The effectiveness of the approach has been showcased in the analysis of the mass spectra of 1,2-dibromoethane and chloroform. Unknown peaks of fragments containing different numbers of bromine or chlorine atoms can be successfully identified.
    Keywords:  Hilbert–Noda Matrix; Isotopic pattern; assignment; orthogonality
    DOI:  https://doi.org/10.1177/00037028261450236
  41. Drug Metab Bioanal. 2026 Jul 06.
    Green and Robust RP-HPLC for Simultaneous Quantification of Gallic, Ferulic, and Caffeic Acids in Human Plasma via Box-Behnken Design-Based Optimization.
    Lalitha Repudi, Mohana Vamsi Nuli, Pavan Kumar Jaini, Ramanjaneyulu Seemaladinne, Kirankumar Chagarlamudi, Kumaraswamy Gandla.
       INTRODUCTION: This study aimed to develop and validate a sustainable reversed-phase high-performance liquid chromatography (RP-HPLC) method for the simultaneous quantification of Gallic Acid (GA), Ferulic Acid (FA), and Caffeic Acid (CA) in human plasma, aligning with green analytical chemistry principles and regulatory guidelines.
    METHODS: Chromatographic conditions were optimized using a Box-Behnken design under the framework of response surface methodology, evaluating the influence of acetonitrile concentration, mobile-phase pH, and flow rate on retention time, peak symmetry, and efficiency. Method validation was performed in accordance with ICH M10 and EC 2002/657/EC guidelines, including assessment of linearity, accuracy, precision, recovery, stability, and matrix effects. The environmental impact of the analytical workflow was assessed using ComplexGAPI, AGREE, AGREEprep, Eco-Scale, and BAGI metrics.
    RESULTS: The optimized chromatographic parameters, 35% acetonitrile, pH 2.8, and a flow rate of 0.6 mL/min, produced well-resolved peaks with retention times of 2.039 min for GA, 3.077 min for FA, and 3.990 min for CA, while yielding minimal deviations (<5%) between predicted and experimental responses. The method demonstrated excellent linearity (R² > 0.999), with limits of detection and quantification ranging from 0.151-1.236 μg/mL and 0.453-3.70 μg/mL, respectively. Accuracy, precision, and recovery were within acceptable regulatory limits. The analytes exhibited robust stability under stress and storage conditions with negligible matrix interference.
    DISCUSSION: The integration of chemometric optimization and multi-tool environmental evaluation confirmed the method's analytical efficiency and ecological compatibility. Compared with conventional RP-HPLC protocols, the proposed workflow significantly reduces solvent usage and hazardous waste generation while maintaining analytical performance.
    CONCLUSION: The developed RP-HPLC method provides a validated, reliable, and environmentally sustainable analytical platform for quantifying phenolic acids in human plasma. Its regulatory compliance, robustness, and reduced ecological footprint make it suitable for routine clinical and pharmacokinetic studies.
    Keywords:  Gallic acid; bioanalytical method; caffeic acid; ferulic acid; green analytical chemistry; quality by design
    DOI:  https://doi.org/10.2174/0118723128455332260605064308
  42. Chromatographia. 2026 Jun;2026
    Evaluating Different C18 Columns for the LC Separation of Δ9-THC and Other Related Cannabinoids.
    Walter B Wilson.
      The best separation possible of delta-9-tetrahydrocannabinol (Δ9-THC) in complex samples via liquid chromatography (LC) is particularly challenging due to the potential for interference from other cannabinoids. Over 100 cannabinoids have been detected in Cannabis sativa plant samples. The separation of Δ9-THC in Cannabis-derived finished products was believed to be easier than plant extracts to analyze at one time because the acidic cannabinoids are converted to their neutral cannabinoids during material preparation. However, the emergence of synthetic or semi-synthetic cannabinoid products, such as delta-8-tetrahydrocannabinol (Δ8-THC), has led to more chromatographic interferences due to the presence of synthetic by-products. The original LC separation method implemented in the Chemical Sciences Division (CSD) at the National Institute of Standards and Technology (NIST) was not acceptable when these chromatographic interferences were present. Within this context, the work presented here explores initial separation of an 11 cannabinoid mixture using different monomeric and polymeric octadecylsilane (C18) columns via liquid chromatography. These columns were characterized using the Standard Reference Material 869b as a three-component column selectivity test mixture to determine if an LC C18 column is classified as monomeric or polymeric. Monomeric C18 columns (NexLeaf C18, ACE 3 C18, and ACE Super C18) provided better separations of the 11 cannabinoids, and baseline separations were obtained in less than 13 min after minor adjustments to the mobile phase program. Using the NexLeaf C18 LC-UV method, mixtures of Δ9-THC and four known chromatographic interferences were analyzed. Cannabinolic acid (CBNA) could not be separated from Δ9-THC; however, CBNA has drastically different absorbance spectra from Δ9-THC, and the co-elution of these cannabinoids can easily be recognized using photodiode array detection. When CBNA is present, the sample can be reanalyzed using an alternate NexLeaf C18 LC-UV method developed here, which baseline-resolves Δ9-THC and CBNA in 60 min. These two LC-UV methods will be further evaluated at NIST CSD through quantitative comparisons in future publications, enabling their use in the development of reference materials for Cannabis plants and/or Cannabis-derived finished products.
    Keywords:  C18 columns; Cannabinoids; Delta-8-tetrahydrocannabinol; Delta-9-tetrahydrocannabinol; Liquid chromatography
    DOI:  https://doi.org/10.1007/s10337-026-04498-9
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