Applied Spectroscopy最新文献

{"title":"Dye-Dependent Fluorescence Enhancement in ZnO Nanorod-Polymer Films: Excitation and Emission Contributions Probed by Time-Resolved Fluorescence.","authors":"Alexandra Falamas, Ioana Cârdan, Denisa Cuibus, Maria Stefan, Cosmin Farcău","doi":"10.1177/00037028261470429","DOIUrl":"10.1177/00037028261470429","url":null,"abstract":"<p><p>The interaction of light with nanostructured materials enables control over emission processes and photonic environments at the nanoscale. In this work, we investigate the dye-dependent fluorescence modulation induced by dielectric nanostructures using thin films based on ZnO nanorods (NRs). Two representative fluorophores with emission spanning the visible spectral range, Nile Blue and Coumarin 6, were embedded in polyvinylpyrrolidone (PVP) spacer layers of varying thicknesses and spin-coated onto ZnO NRs films prepared by a drop-coating protocol. Steady-state and time-resolved fluorescence spectroscopy were employed to quantify modifications in emission intensity and excited state dynamics arising from the interaction between the fluorophores and the nanostructured substrate. Both dyes exhibited pronounced fluorescence enhancement in the presence of the ZnO NRs, reaching up to ∼ 15× for Nile Blue and ∼ 9× for Coumarin 6 relative to glass substrates, dependent on the PVP layer thickness. Time-correlated single photon counting measurements revealed modest lifetime reductions upon deposition on ZnO, indicating that fluorescence enhancement is not dominated by strong radiative-rate modification or interfacial charge transfer. The results suggest that the observed emission amplification arises from a combination of excitation-field enhancement and improved emission extraction mediated by wavelength-dependent scattering from the ZnO NRs. The excitation-wavelength dependence of the enhancement is consistent with scattering-assisted redistribution of the excitation light, which may increase the effective excitation experienced by the fluorophores. Additionally, numerical aperture-dependent fluorescence measurements and polarization-resolved anisotropy investigations are consistent with scattering-assisted redistribution and extraction of emitter photons that would otherwise remain partially trapped within the PVP film by total internal reflection (TIR).</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261470429"},"PeriodicalIF":2.2,"publicationDate":"2026-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148395526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EXPRESS: Identification of Unknown Peaks in Mass Spectra Based on the Characteristic Isotopic Pattern via the Hilbert-Noda Matrix.","authors":"Ying Liu, Lei Gao, Anqi He, Honggang Nie, Limin Yang, Yukihiro Ozaki, Isao Noda, Yizhuang Xu","doi":"10.1177/00037028261450236","DOIUrl":"https://doi.org/10.1177/00037028261450236","url":null,"abstract":"<p><p>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.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261450236"},"PeriodicalIF":2.2,"publicationDate":"2026-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148395610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Precursor/Fragment Ion Identification from Bulk Analysis of a Mixture through Two-Dimensional Correlation Mass Spectrometry.","authors":"Elly A Breves, Garon H Lowke, Jacob T Shelley","doi":"10.1177/00037028261470406","DOIUrl":"10.1177/00037028261470406","url":null,"abstract":"<p><p>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.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261470406"},"PeriodicalIF":2.2,"publicationDate":"2026-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148395544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-Reflectance-Spectroscopy, Part III: In-Line Monitoring of Milk Fat Globule Size via Sauter Diameter Using an Optical Sensor.","authors":"Sebastian Boldt, Gert Sinn, Klaus-Henrik Mittenzwey, Ouwen Zhai, Henry Mittenzwey, Dietmar Lerche, Marco Gleiß, Hermann Nirschl","doi":"10.1177/00037028261440919","DOIUrl":"10.1177/00037028261440919","url":null,"abstract":"<p><p>In milk-based formulations, fat globule size is a fundamental quality parameter. Accurate measurement of globule size is critical for ensuring consistent product performance, preferably through in-line monitoring. However, most conventional techniques are off-line and unsuitable for integration into manufacturing processes. The objective of this study was to demonstrate the feasibility of a recently developed optical sensor based on Multi-Reflectance Spectroscopy (MRS) for in-line estimation of the fat globule Sauter diameter. The MRS sensor acquires multidimensional reflectance data across multiple wavelengths and defined illumination-detection geometries. Industrial validation was performed in a milk standardization plant using low-fat (1.5 wt%) and whole-fat (3.5 wt%) milk. Fat globule sizes were systematically varied by stepwise adjustment of homogenization pressure. Reference globule size distributions were obtained via analytical centrifugation and expressed as the Sauter diameter. Analytical reflectances derived from the reference size distributions were compared with experimental spectra to assess globule size dependency of the optical responses. Principal component analysis revealed a clear separation between fat concentration levels, motivating the development of concentration-specific partial least squares regression models. Two PLS models were trained and validated using independent datasets. Across the combined concentration range and full Sauter diameter span (0.7-3.5 <math><mi>μ</mi></math>m), resultet in a test RMSE of 271 nm. For the separate 1.5 and 3.5 wt% fat lines, RMSE values of approximately 80 and 40 nm were obtained, respectively. These results demonstrate that the MRS-based optical sensor enables accurate, real-time in-line monitoring of fat globule size in complex dairy emulsions and represents a promising process-analytical tool for industrial process control.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"774-785"},"PeriodicalIF":2.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147760573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectral Similarity Analysis of Camphor-10-Sulphonic Acid: A System Suitability Standard for Circular Dichroism in Quality Regulated Environments.","authors":"Christopher Jones","doi":"10.1177/00037028261437102","DOIUrl":"10.1177/00037028261437102","url":null,"abstract":"<p><p>Spectral similarity supports comparison of circular dichroism (CD) spectra by using all datapoints to improve alignment of wavelength, intensity and offset. CD is increasingly used to confirm the higher order structure and stability of biopharmaceutical proteins, which requires method validation and assessment of robustness in quality regulated analytical systems. Camphor-10-sulphonic acid (CSA), or its ammonium salt, is widely used to calibrate spectropolarimeters, with its use specified in the European Pharmacopoeia (EP), and, more broadly, as a system suitability standard. Spectral similarity comparison of 75 CSA reference spectra in the Protein Circular Dichroism Data Bank (PCDDB) showed the potential value of this approach to monitor instrument performance and support compliance within a quality system.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"734-742"},"PeriodicalIF":2.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147760611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Validated Reference Database for Twentieth-Century Cd-Based Pigments: Integrated Structural and Compositional Characterization.","authors":"Jacopo Orsilli, Simone Caglio, Marine Cotte, Francesco d'Acapito, Giulia Tamburini, Chiara Ferrara, Anna Galli","doi":"10.1177/00037028261468366","DOIUrl":"10.1177/00037028261468366","url":null,"abstract":"<p><p>Cadmium sulfur selenide and cadmium zinc sulfide pigments have been widely employed by artists of the twentieth century. A deep knowledge of these artworks, also in view of their conservation and/or restoration, relies on comprehensive and robust databases of reference materials of the pigments to easily detect their composition and their tendency and routes to deterioration. In this work, we initiate the construction of such a database by applying exclusively non-invasive techniques, X-ray fluorescence (XRF) and fiber optics reflectance spectroscopy (FORS) in the visible to shortwave (Vis-SWIR) range, to two sets of historical pigments: a group of pure commercial tube paints and a mixed palette representative of artistic practice. To strengthen the interpretative framework, mock-up samples were prepared using modern Cd-based pigments. These reference materials were first analysed using the same non-invasive protocols to ensure full data compatibility. In addition, they were further characterized through synchrotron-based techniques, namely high-hesolution X-ray powder diffraction (HR-XRPD) and X-ray absorption spectroscopy (XAS), providing additional structural and phase information not accessible through laboratory non-invasive methods alone. The integration of non-invasive and synchrotron-based data on the modern reference materials enables a more rigorous interpretation of the spectra collected on historical pigments. This combined approach enhances phase discrimination, compositional assessment, and the understanding of pigment variability, thereby increasing the reliability and internal consistency of the historical database. The resulting dataset establishes a solid foundation for future non-invasive studies of twentieth-century Cd-based pigments in complex stratigraphic and binding media contexts.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261468366"},"PeriodicalIF":2.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148359161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-Parameter Wavelength Characterization of Array Spectrometers Under Near-Limit Sampling Conditions.","authors":"Du Bo, Liu Liying, Wu Dongli, Wu Zhifeng, Zheng Feng, Liu Cong, Li Ning, Zhang Jing, Zhang Shihao","doi":"10.1177/00037028261468369","DOIUrl":"10.1177/00037028261468369","url":null,"abstract":"<p><p>Accurate wavelength characterization is essential for high-precision spectral measurements, particularly in applications such as solar-induced chlorophyll fluorescence (SIF) retrieval, where weak spectral signals are highly sensitive to instrument performance. In array spectrometers, characteristic wavelengths can be defined by peak, center, or centroid positions, whereas spectral resolution is commonly represented by full width at half-maximum (FWHM) or equivalent rectangular width (ERW). This study systematically investigates the influence of sampling conditions on wavelength characterization using a crossed Czerny-Turner array spectrometer operating over the 650-800 nm spectral range. The concept of sampling ratio is employed to define near-limit sampling conditions, in which monochromatic spectral peaks are represented by only 2-5 detector pixels. Experimental results show that the spectrometer predominantly operates within this regime. Under these conditions, significant discrepancies arise among different characteristic wavelength definitions owing to the combined effects of discrete sampling and spectral peak shape. Peak-based wavelength estimation is primarily affected by local sampling variations, whereas centroid-based definitions are more sensitive to energy distribution and peak asymmetry. Furthermore, a systematic divergence between ERW and FWHM demonstrates that spectral resolution metrics depend not only on geometric peak width but also on spectral energy distribution, particularly under non-ideal imaging conditions. These results show that wavelength characterization should be regarded as a coupled problem involving sampling conditions, spectral peak representation, and resolution metrics rather than as independent parameters. The proposed multi-parameter characterization approach establishes a practical framework by clarifying the relationships among sampling ratio, characteristic wavelength definitions, and spectral resolution, introducing two deviation metrics to quantify inconsistencies among wavelength definitions, and revealing the complementary physical significance of FWHM and ERW from geometric and energy-distribution perspectives. This approach provides a physically interpretable basis for wavelength calibration, spectral resolution evaluation, and performance assessment of array spectrometers operating under near-limit sampling conditions.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261468369"},"PeriodicalIF":2.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148359182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stacked Machine Learning for Timber Identification Using Laser-Induced Breakdown Spectroscopy (LIBS).","authors":"Helder V Carneiro, Erin R Price, Kierra R Cano, Caelin P Celani, James A Jordan, Kent M Elliott, Karl S Booksh","doi":"10.1177/00037028261444395","DOIUrl":"10.1177/00037028261444395","url":null,"abstract":"<p><p>This study presents a new approach to wood species identification using laser-induced breakdown spectroscopy (LIBS) combined with stacked machine learning techniques. The research analyzed 700 samples comprising nine <i>Dalbergia</i> species and nine additional tropical timber species, utilizing a handheld LIBS analyzer. A stacking methodology was developed by integrating three support vector machine (SVM) models with different kernel functions (linear, polynomial, and radial) in a one-versus-all (OVA) configuration. These SVM outputs were then combined using a partial least squares discriminant analysis (PLS-DA) meta-learner. Through PCA-based variable selection, the dimensionality was reduced from 23 401 to wavelengths while maintaining classification accuracy. The stacking approach achieved a Cohen's kappa value of 0.8671 in the validation set, significantly outperforming traditional flat classifiers. Variable importance analysis revealed calcium, magnesium, and barium as crucial elements for species differentiation, with their concentrations reflecting environmental conditions and geographical origins. This research demonstrates the potential of combining LIBS spectroscopy with advanced machine learning techniques for rapid, non-invasive timber identification, which can support efforts against illegal logging and enforcement of international trade regulations.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"720-733"},"PeriodicalIF":2.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147760585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantitative Diagnostics of Hydroxyl (OH) Radicals in Methane-Air Flames Using Wavelength Modulation Spectroscopy with Correction for Water Spectral Interference.","authors":"Jiyeon Park, Aran Song, Changkook Ryu, Daehae Kim, Miyeon Yoo, Changyeop Lee","doi":"10.1177/00037028261450621","DOIUrl":"10.1177/00037028261450621","url":null,"abstract":"<p><p>Exhaust gases generated by fossil fuel combustion significantly contribute to air pollution and climate change, emphasizing the need for efficient combustion diagnostics. OH radicals are key indicators of flame behavior; however, conventional laser-induced fluorescence (LIF) techniques are impractical for industrial monitoring due to their complexity. In this study, wavelength modulation spectroscopy (WMS) employing a near-infrared laser at 1.49 μm was used to measure OH radical concentrations, incorporating a correction for spectral interference from H₂O. A wavelength division multiplexer (WDM) was used to enable the simultaneous operation of two lasers at 1.49 μm (OH) and 1.39 μm (H₂O, temperature), allowing for correction of water interference. OH concentrations were determined using both WMS and direct absorption spectroscopy (DAS), and the results were evaluated through comparison with CHEMKIN simulations. The proposed dual-laser system demonstrated reliable and interference-corrected quantification of OH radicals in methane (CH₄)/air premixed flames over a range of equivalence ratios. Comparisons with thermocouple-based temperature measurements and CHEMKIN-predicted species concentrations confirmed the reliability of the proposed technique. This study highlights the robustness and applicability of WMS-based OH diagnostics for combustion monitoring and demonstrates the potential for future implementation in industrial burner systems.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"692-704"},"PeriodicalIF":2.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148013267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deterministic Compressed Sensing in Time-Domain Spectroscopy.","authors":"Yookyung Ha, Jonas Woeste, Dominic A Azih, Nikola Stojanovic, Peter Jung, Michael Gensch","doi":"10.1177/00037028261465699","DOIUrl":"10.1177/00037028261465699","url":null,"abstract":"<p><p>We demonstrate for the first time, that compressed sensing with deterministic sampling points enables to perform time-domain spectroscopy with sub-Nyquist sampling. Our results pave the way for on-chip time-domain spectroscopy devices, currently envisioned for a new generation of compact sensors.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261465699"},"PeriodicalIF":2.2,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148359130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}