ACS Measurement Science Au最新文献

{"title":"Segmental Mechanobiology of Normal and Glaucomatous Human Trabecular Meshwork Cells.","authors":"Alireza Karimi, Hasti Golchin, Ansel Stanik, Nikaansh Singh, Pretham Nandakumar, Tia Harbaugh, Mithran Ganesan, Mini Aga, Elizabeth White, Mary Kelley, Ted Acott","doi":"10.1021/acsmeasuresciau.5c00206","DOIUrl":"https://doi.org/10.1021/acsmeasuresciau.5c00206","url":null,"abstract":"<p><p>Glaucoma is a leading cause of irreversible blindness worldwide, with elevated intraocular pressure (IOP) serving as the major risk factor for disease onset and progression. IOP is largely determined by aqueous humor outflow resistance in the conventional pathway, where interactions between trabecular meshwork (TM) cells and the surrounding extracellular matrix (ECM) are pivotal. In this study, we examined the segmental mechanobiology of normal and glaucomatous human TM cells isolated from high-flow (HF) and low-flow (LF) regions of the outflow pathway of normal and primary open-angle glaucoma (both male and female). Cells were seeded on type I collagen gels with fibrillar elastic moduli of 4.7 kPa and 27.7 kPa to approximate the ECM conditions of normal and glaucomatous eyes, respectively. We employed 3D traction force microscopy to quantify time-dependent contractile forces in the cells as well as curl, divergence, orientation, and tensile strain in the collagen fibers within 12 h postseeding. We also analyzed the organization of actin, microtubule, and intermediate filaments in normal and glaucomatous TM cells from both HF and LF regions. Multivariable mixed-effects models showed that, after accounting for fibrillar stiffness, time, normal/glaucoma status, and sex, HF cells generated ∼1.6-fold higher mean traction (window averaged, ∼5-6 cells) and ∼1.4-fold higher tensile strain than LF cells and induced ∼1.5-fold greater collagen curl (<i>p</i> < 0.001 for all), whereas divergence and glaucoma versus normal difference were not significant in this data set. Stiffer gels increased the collagen fibril preferred orientation angle (HF > LF), and glaucomatous LF cells showed persistently disorganized actin and microtubules with little change in intermediate filaments. These findings emphasize the importance of segmental cell-ECM interactions in modulating cell-ECM interaction.</p>","PeriodicalId":29800,"journal":{"name":"ACS Measurement Science Au","volume":"6 2","pages":"517-534"},"PeriodicalIF":4.6,"publicationDate":"2026-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13087962/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147723962","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Lightweight Data-Augmented Deep Learning Framework for Real-Time Instance Segmentation in Liquid-Phase In Situ Transmission Electron Microscopy.","authors":"Ming-Hao Shen, Wei-Che Chang, Wen-Huei Chu, Yu-Hsuan Cheng, Shih-Wen Tseng, Shu-Han Hsu","doi":"10.1021/acsmeasuresciau.5c00199","DOIUrl":"https://doi.org/10.1021/acsmeasuresciau.5c00199","url":null,"abstract":"<p><p>Liquid-phase transmission electron microscopy (LPTEM) offers critical insights into the dynamic behaviors of materials, but automated analysis is hindered by the scarcity of annotated data and the high cost of image acquisition. To address these challenges, we propose an LPTEM deep learning framework that (i) closes the annotation gap, (ii) localizes nanoparticles through real-time detection, and (iii) preserves per-pixel detail. Through CycleGAN, we are able to generate a large number of images that are style-consistent with real LPTEM frames, effectively expanding the data set without manual labeling. After augmenting the data set, our fine-tuned YOLOv11n model achieves 97.66% precision and 99.05% mAP50 for detecting nanoparticles, closely approaching the performance of models trained on real data. Three Mobile-UNet variants, optimized for different computational efficiency and accuracy trade-offs, demonstrate instance segmentation for in situ TEM with intersection over union (IoU) scores ranging from 0.8685 to 0.9207 (on a scale where 1.0 indicates perfect overlap with the ground truth), indicating highly accurate particle shapes. Our integrated framework significantly enhances real-time detection and segmentation performance of nanoparticles in LPTEM, with YOLO + Mobile-UNet Slim achieving a real-time processing speed of 102.34 FPS. This framework establishes a scalable, annotation-efficient route to high-precision, real-time LPTEM analysis, opening the door to autonomous in situ experiments and accelerated materials discovery.</p>","PeriodicalId":29800,"journal":{"name":"ACS Measurement Science Au","volume":"6 2","pages":"476-487"},"PeriodicalIF":4.6,"publicationDate":"2026-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13087949/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147723833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Expanding the Capabilities of Portable Mapping in Macroscopic External Reflection FT-IR through a Targeted Data-Driven Spectral Enhancement and Denoising Strategy.","authors":"Zelan Li, Emilio Catelli, Jošt Stergar, Matija Milanič, Roberto Sáez-Hernández, Silvia Prati, Paolo Oliveri, Giorgia Sciutto","doi":"10.1021/acsmeasuresciau.5c00163","DOIUrl":"https://doi.org/10.1021/acsmeasuresciau.5c00163","url":null,"abstract":"<p><p>Reliable spectral quality is essential for extracting meaningful information from infrared reflectance data, particularly when using portable systems with limited scan numbers. This study presents a data-driven spectral enhancement workflow designed to improve the interpretability of portable macroscopic external reflection Fourier Transform Infrared (MA-rFT-IR) mapping systems developed by the Authors, operating in the near- and mid-infrared (NIR-MIR) ranges. Despite the growing use of reflectance imaging spectroscopy, limited attention has been devoted to the development of robust denoising strategies capable of minimizing noise and unwanted variability while preserving spectral quality and enabling more reliable and accurate data analysis. This study proposes a broadly applicable processing framework aimed at enhancing the efficiency and performance of reflectance-based spectral analysis. Denoising methods including Savitzky-Golay filtering and wavelet- and PCA-based denoising were tested and evaluated individually and in combination. Quantitative performance was assessed using arccosine similarity (ACOS) and derivative-based root-mean-square error (dRMSE) metrics across selected spectral regions of interest, with a derivative ACOS (dACOS) index applied to monitor band-shape variations. The evaluation results were integrated through Pareto analysis to identify the optimal trade-off between noise reduction and spectral-feature preservation. Application of the proposed approach to a multilayered painting mock-up demonstrated that the enhancing spectral data workflow preserves key diagnostic features revealing subtle spectral bands. Furthermore, applying multivariate curve resolution-alternating least-squares (MCR-ALS) to the denoised data enabled chemically meaningful separation of complex overlapping signals, improving the interpretability of compositional information compared with traditional denoising methods and data processing. The workflow strengthens the analytical reliability of low-scan reflection-mode data and provides a transferable framework for optimizing denoising strategies in portable infrared applications.</p>","PeriodicalId":29800,"journal":{"name":"ACS Measurement Science Au","volume":"6 2","pages":"361-373"},"PeriodicalIF":4.6,"publicationDate":"2026-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13087942/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147723832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Symmetrical pH Electrochemical Cell Coupled to Constant Potential Coulometry for Improved Sensitivity and Precision: Part 2. Submersible Probe for In Situ Measurements.","authors":"Robin Nussbaum, Stéphane Jeanneret, Thomas Cherubini, Mary-Lou Tercier-Waeber, Dario Omanović, Eric Bakker","doi":"10.1021/acsmeasuresciau.5c00198","DOIUrl":"https://doi.org/10.1021/acsmeasuresciau.5c00198","url":null,"abstract":"<p><p>Seawater pH is a critical parameter influencing many processes in the ocean. Today it is mainly measured by indicator-based spectrophotometry to allow for high precision. This, however, is at the expense of traceability and systematic errors originating from changes in temperature, salinity, and other matrix effects. Moreover, in routine practice, this approach is not performed in situ and requires sampling and manual manipulations, which are prone to introduce additional errors, including gas exchange with the atmosphere. Unfortunately, in the last few decades, the electrochemical sensing community has failed to make efforts to improve the performance of the main method, which is potentiometric detection with pH glass electrodes. To address this, we aim here to improve the sensitivity and precision of submersible pH probes on the basis of pH glass electrodes by minimizing systematic errors from temperature changes and by implementing a recently described coulometric method. The electrodes are mounted in a symmetrical cell reported in part 1 of this work to reduce sensor drift and minimize inaccuracies due to liquid junction potential variations and pH changes of the inner solution from temperature fluctuations. The development and construction of the probe are explained. The circuit is evaluated, and the sensors are calibrated over a range of temperatures, approaching ideal behavior. The submersible probe was deployed in situ in April 2025 in the vertically stratified Krka River Estuary in Croatia. The precision of the probe was evaluated in situ by stability experiments in the seawater layer. The determined precision is 0.001 pH unit, which is significantly better than that reported earlier for routine pH probes. A recalibration procedure with synthetic seawater is also evaluated for minimizing drift. A depth profile with a changing salinity was performed and compared with multiparameter probes.</p>","PeriodicalId":29800,"journal":{"name":"ACS Measurement Science Au","volume":"6 2","pages":"497-506"},"PeriodicalIF":4.6,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13087930/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147722609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Electroanalytical Methods to Establish the Role of Buffer and Electrolyte Components in Water Denitrification Using a Copper-Based Bioinspired Electrocatalyst.","authors":"Vanessa A Hulse, Katy A Knecht, Frank R Fronczek, Noémie Elgrishi","doi":"10.1021/acsmeasuresciau.5c00203","DOIUrl":"https://doi.org/10.1021/acsmeasuresciau.5c00203","url":null,"abstract":"<p><p>The overuse of fertilizers in modern agricultural practices has contributed to the accumulation of nitrogen oxyanions in water systems. These nitrogen oxyanions, including nitrite and nitrate, pose risks to human and marine health. Of these contaminants, nitrite is especially problematic for aquatic life. Chemical methods for reducing nitrite in water are limited by cost and by the risk of secondary contamination. The electrochemical reduction of nitrite is a promising method to solve these issues. Here we report the electrocatalytic reduction of nitrite to nitric oxide in quantitative Faradaic yields with a copper-based electrocatalyst. Electroanalytical methods enable the discussion of mechanistic details, in particular with respect to the catalyst resting state as well as the unexpected role of the buffer and other electrolyte components on electrochemical activity. This work emphasizes the noninnocence of buffers and other electrolyte components, the choice of which should be of critical importance when evaluating the electrochemical activity of new homogeneous electrocatalysts.</p>","PeriodicalId":29800,"journal":{"name":"ACS Measurement Science Au","volume":"6 2","pages":"507-516"},"PeriodicalIF":4.6,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13087953/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147723795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Symmetrical pH Electrochemical Cell Coupled to Constant Potential Coulometry for Improved Sensitivity and Precision: Part 1. Fundamental Considerations.","authors":"Robin Nussbaum, Stéphane Jeanneret, Thomas Cherubini, Eric Bakker","doi":"10.1021/acsmeasuresciau.5c00197","DOIUrl":"10.1021/acsmeasuresciau.5c00197","url":null,"abstract":"<p><p>pH is a major variable in complex aquatic ecosystems, influencing biological activity, metal speciation and more. The method to routinely measure pH is potentiometric measurements with a glass electrode connected to a reference Ag/AgCl element in contact with the sample through a liquid junction. However, it has been largely replaced by optical pH assays in the field of seawater pH measurements because much better precisions could be achieved. Glass electrodes also suffer from bias such as liquid junction potential changes and temperature influence on the inner solution pH that generate inaccuracies. Moreover, the Nernstian relationship between observed potential and pH results in limited sensitivity. To overcome these limitations, an alternative readout called constant potential coulometry is implemented in the measurement system for increased sensitivity. A symmetrical pH cell is proposed in which two identical glass electrodes, separated by an open 3 M KCl channel, are measured against each other. One of them is kept in a NIST buffer while the other is used to measure the pH of the sample or the calibrant solution. Glass electrodes are evaluated at different temperatures in NIST buffers versus a classical reference electrode and versus each other in a symmetrical flow cell. The latter features open junctions that should improve the repeatability of the liquid junction potential. The determined signal repeatability in a single sample is as low as 0.3 mpH with a precision for consecutive samples of 0.001 pH, which is drastically improved over routinely available pH probes.</p>","PeriodicalId":29800,"journal":{"name":"ACS Measurement Science Au","volume":"6 2","pages":"488-496"},"PeriodicalIF":4.6,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13087951/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147722585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Applications of Nanopipettes in Scanning Ion Conductance Microscopy for High-Spatial-Resolution Topographic Imaging and Sensing in Single Cells.","authors":"Yusuf Muhammed, Ana B Ramirez, Robert A Lazenby","doi":"10.1021/acsmeasuresciau.5c00192","DOIUrl":"10.1021/acsmeasuresciau.5c00192","url":null,"abstract":"<p><p>Membrane structures and cellular phenomena have been studied using scanning ion conductance microscopy (SICM). Conventional techniques for studying single cells, such as optical microscopy, fluorescence microscopy, electron microscopy (EM), and atomic force microscopy (AFM), have provided a wealth of information on the architecture of cell membranes, but they could potentially be invasive to live cells due to reasons including phototoxicity, electron beam damage, and cantilever-mediated damage to the cell membrane. While super-resolution approaches such as stimulated emission depletion (STED) microscopy have extended the capabilities of optical imaging, conventional optical microscopy remains limited by the diffraction limit in resolving intricate structures on cell membranes. In this review article, we discuss SICM as a technique that allows noninvasive imaging of live single cells in aqueous solutions, including cell culture media. We also discuss the fabrication and characterization of nanopipettes, advances in instrumentation and scanning regimes used in SICM, and applications of nanopipettes in the technique for topography mapping, high spatial resolution imaging, precise delivery of molecules to cells, biopsy, and surface charge measurements. We also discuss how nanopipettes are functionalized for applications in the simultaneous mapping of cell topography and high spatial resolution sensing, such as extracellular pH mapping. SICM has also been combined with scanning electrochemical microscopy (SECM) to enable the measurement of electroactive species at the cell membrane, and applied in cell surface charge mapping, where membrane charge is implicated in many cellular events. Advances in SICM imaging speed will allow the capture of fast cellular phenomena, and because the application of nanopipettes in SICM for high spatial resolution topographic imaging and sensing is still in its infancy, these developments could open new opportunities for imaging the distribution of analytes around live single cells.</p>","PeriodicalId":29800,"journal":{"name":"ACS Measurement Science Au","volume":"6 2","pages":"255-279"},"PeriodicalIF":4.6,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13087940/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147723848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uncertainties in Calibration of an Optical Spectrometer for Measuring Isotope Ratios in Methane.","authors":"Christopher Rennick, Emmal Safi, Aimee Hillier, Emily Hopkinson, Ruth E Hill-Pearce, Tim Arnold","doi":"10.1021/acsmeasuresciau.5c00094","DOIUrl":"10.1021/acsmeasuresciau.5c00094","url":null,"abstract":"<p><p>The stable isotope ratios of carbon (δ¹³C-(CH₄)) and hydrogen (δ²H-(CH₄)) in methane (CH₄) from atmospheric air samples provide a tracer that can help distinguish the relative contribution of emission sources. These can be continuously measured at atmospheric monitoring stations by optical isotope ratio spectrometer (OIRS) instruments, providing data that is complementary to isotope ratio mass spectrometry (IRMS) measurements. OIRS instruments directly measure the amount fraction of the ¹²CH₄, ¹³CH₄, and ¹²CH₃ ²H isotopologues, in contrast to the IRMS method of conversion to CO₂ and H₂, so they have different calibration needs related to reference materials (RMs) and analysis protocol. We use a single high-purity source of CH₄, which has been isotopically characterized by IRMS, to produce two calibration RMs that bracket the sample in amount fraction. The isotope ratio measurement is calibrated via the isotopologue amount fraction, which is used to derive analytical expressions for the combined uncertainty. We test this approach using a 550 μmol mol^-1 sample (representative of the amount fraction produced from air sampled by the NPL preconcentrator) prepared from a separate CH₄ source. The combined standard uncertainty for the isotope ratio of this sample is 0.19 ‰ for δ¹³C-(CH₄) and 1.1 ‰ for δ²H-(CH₄), including uncertainty contributions from the isotopic assignment of the CH₄ used for the RMs, their gravimetric preparation, and the spectrometer noise. The dominant contribution to this is from the uncertainty in isotopic assignment of the CH₄ used in RM preparation. The next largest contribution to the uncertainty budget is the measurement noise, estimated from the Allan-Werle deviation, and the smallest contribution is from the preparation uncertainty in the total CH₄ amount fraction in the RMs. We demonstrate that preparing the bracketing RMs from a common CH₄ source results in correlations between isotopologue amount fractions and that neglecting this leads to an overestimation of the isotope ratio uncertainty.</p>","PeriodicalId":29800,"journal":{"name":"ACS Measurement Science Au","volume":"6 2","pages":"291-302"},"PeriodicalIF":4.6,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13087954/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147723662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anticancer LNA Oligonucleotides Detection through a Simple Paper-Based Platform.","authors":"Ada Raucci, Giovanna Liciberto, Michele Guida, Thomas Lee Moore, Canio Martinelli, Michelino De Laurentiis, Antonio Giordano, Stefano Cinti","doi":"10.1021/acsmeasuresciau.5c00164","DOIUrl":"10.1021/acsmeasuresciau.5c00164","url":null,"abstract":"<p><p>Locked nucleic acids (LNAs) are chemically modified oligonucleotides widely used in gene silencing and precision oncology, yet their clinical translation is limited by the absence of simple, rapid assays to quantify them directly in biological fluids for dose optimization and timely therapeutic feedback. Here, we report a paper-based electrochemical biosensor for the direct detection of antisense LNA oligonucleotides using LNA-anti-miR-155 as a clinically relevant model. The platform employs a methylene blue-labeled RNA probe that mimics the native miRNA target and yield a signal-off voltammetric response upon hybridization. The disposable, gold nanoparticle-modified paper electrodes support picomolar detection limits, high reproducibility, and reliable performance in undiluted human plasma without sample pretreatment. By combining portability, low cost, and rapid analysis in a single-use format, this biosensor advances point-of-care monitoring of LNA-based therapeutics and provides a versatile blueprint for future personalized treatment platforms targeting antisense oligonucleotides.</p>","PeriodicalId":29800,"journal":{"name":"ACS Measurement Science Au","volume":"6 2","pages":"374-381"},"PeriodicalIF":4.6,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13087959/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147723850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular-Level Characterization of Carbonaceous Aerosols via Coupled Thermal-Optical Carbon Analysis and Ultra-High-Resolution FT-ICR Mass Spectrometry.","authors":"Silvia Juliana Vesga-Martínez, Christopher Paul Rüger, Fabian Etscheidt, Martin Bauer, Patrick Martens, Anika Neumann, Hendryk Czech, Ralf Zimmermann","doi":"10.1021/acsmeasuresciau.5c00170","DOIUrl":"10.1021/acsmeasuresciau.5c00170","url":null,"abstract":"<p><p>Comprehensive molecular-level characterization of carbonaceous aerosols is essential for understanding their environmental transformations, optical properties, and health effects. Here, we present a hyphenated analytical approach combining a thermal-optical carbon analyzer (TOCA) with atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI-FT-ICR-MS) for the direct, temperature-resolved molecular analysis of particulate matter (PM). The method enables the simultaneous quantification and chemical speciation of evolved organic and elemental carbon fractions, following the IMPROVE_A protocol, thereby distinguishing between organic and elemental carbon fractions. The system achieves subppm mass accuracy and resolving power exceeding 2.6 × 10⁵ at <i>m</i>/<i>z</i> 400, ensuring reliable differentiation of critical mass splits such as C₃ vs SH₄ (3.4 mDa) and allowing the unambiguous assignment of thousands of sum formulas across complex aerosol matrices. Compared with resonance-enhanced multiphoton ionization time-of-flight MS, the APPI-FT-ICR-MS coupling expands the accessible chemical space toward oxygenated and sulfur-containing species while maintaining robust performance and reproducibility. Application to representative aerosol sources, including ship diesel emissions, residential wood combustion, and ambient PM from Beijing, demonstrated distinct molecular fingerprints. Ship emissions were dominated by CH- and CHS-class species with double bond equivalents (DBE) ≤20, indicative of alkylated polycyclic aromatics, whereas wood combustion particles contained more oxidized CHO- and CHNO-classes with enhanced aromaticity and nitrogen incorporation. Ambient aerosols exhibited mixed signatures with elevated OC/EC ratios (∼3-4) and high contributions from oxygenated and nitrate-bearing compounds, reflecting secondary formation and seasonal variability. This integrated TOCA-APPI-FT-ICR-MS approach provides unprecedented resolution of thermally evolved aerosol species, bridging operational OC/EC quantification with molecular-level speciation. By correlating volatility, aromaticity, and oxidation state across source types, it establishes a powerful framework for tracing aerosol origins, transformation processes, and their environmental and health relevance.</p>","PeriodicalId":29800,"journal":{"name":"ACS Measurement Science Au","volume":"6 2","pages":"395-410"},"PeriodicalIF":4.6,"publicationDate":"2026-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13087955/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147723956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}