Applied Spectroscopy最新文献

{"title":"EXPRESS: Prediction of the Molecular Weight of Polyethylene Using Raman Spectroscopy with Multivariate Data Analysis.","authors":"Ayano Kitamura, Naoya Okitsu, Harumi Sato","doi":"10.1177/00037028261486542","DOIUrl":"https://doi.org/10.1177/00037028261486542","url":null,"abstract":"<p><p>In this study, a simple procedure to estimate the molecular weight of high-density polyethylene over a very wide range of molecular weights was investigated using Raman spectroscopy with multivariate data analysis. High-density polyethylene samples with viscosity average molecular weights (Mv) [g/mol] ranging from 0.1 to 7.4 million were synthesized, and their Raman spectra in the 3200 to 100 cm^-1 region were measured. Using multivariate analysis to develop a calibration model derived from each spectrum and molecular weight, a high correlation coefficient was achieved between the predicted and actual values of the model. Thus, this study shows that Raman spectroscopic method can be employed for estimating the molecular weight of high-density polyethylene. Furthermore, Raman spectroscopy can be implemented in optical systems utilizing optical fibers, enabling operation with the measurement point separated from the main device even in harsh process environments, including high temperatures. Consequently, this technique is highly resistant to environmental conditions and is extremely useful as a measurement method applicable in any measurement environment. In practical applications, the spectroscopic technique will be selected according to the purpose and measurement environment, aiming for industrial application of this method.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261486542"},"PeriodicalIF":2.2,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148890922","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: Development of dynamic time-over-threshold method for signal processing in cavity ring-down spectroscopy.","authors":"Konrad Kleineidam, Ryohei Terabayashi, Takumi Mochizuki, Erik Thiel, Klaus Wendt, Norihiko Nishizawa, Kenji Shimazoe, Hideki Tomita","doi":"10.1177/00037028261486533","DOIUrl":"https://doi.org/10.1177/00037028261486533","url":null,"abstract":"<p><p>Cavity ring-down spectroscopy (CRDS) enables highly sensitive detection of trace gases but typically requires high-speed, high-resolution digitizers for exponential fitting of the measured \"ring-down\" decay signals. This work investigates a simplified signal processing approach based on the Time-over-Threshold (ToT) method, using only threshold crossing times instead of full waveform acquisition. In contrast to the ToT method with static thresholds, dynamic threshold signals are employed to improve linearity and robustness with respect to signal amplitude variations. The proposed dynamic ToT method is implemented using a compact analog circuit and evaluated using a mid-infrared CRDS setup for CO₂ measurement. Experimental results demonstrate good agreement with conventional fitting, with improved reliability compared to the ToT method with static thresholds and comparable linearity over a broad range of ring-down decay rates. These findings establish the dynamic ToT method as an accessible and scalable alternative for acquiring decay data in CRDS, particularly suited for simultaneous multi-channel or multi-wavelength measurements.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261486533"},"PeriodicalIF":2.2,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148890866","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: ICP-MS Analysis of Pipe Tobacco Using Calibration by Proxy.","authors":"Hanieh Helli, Willis B Jones, Beatriz M Fontoura, Bradley T Jones","doi":"10.1177/00037028261486540","DOIUrl":"https://doi.org/10.1177/00037028261486540","url":null,"abstract":"<p><p>Calibration by Proxy (CbPx) is applied to the inductively coupled plasma mass spectrometry analysis of seven commercial pipe tobacco samples. Five proxy elements are employed to construct a single calibration curve that applies to every analyte in the sample. Both the preparation of the calibration curve and the multielement analysis of each sample is performed from the analysis of just two solutions. The analysis of a standard reference material (tomato leaves) demonstrates excellent recoveries for 12 test elements, ranging from 77% (Ni) to 104% (Cu), with relative standard deviations averaging 6.6%. Detection limits are in the ppb range (µg analyte per kg leaf). Pipe tobacco samples containing between 0.04 and 700 mg analyte per kg leaf are analyzed for Al, As, Ba, Cd, Cu, Fe, Mn, Mo, Ni, Pb, V, and Zn.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261486540"},"PeriodicalIF":2.2,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148890894","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: Hyperspectral Unmixing for Orthopedic Tissue Identification Under Spectral Variability and Material Overlap.","authors":"Bouchra Abdel Aziz, Nadine Abdallah Saab, Amani Raad, Olga Assainova, Mohamad Khalil, Marwa El Bouz","doi":"10.1177/00037028261469566","DOIUrl":"https://doi.org/10.1177/00037028261469566","url":null,"abstract":"<p><p>Enhancing surgical precision through automated tissue identification requires overcoming the complexities of real operative scenes. Specifically, material detection is complicated by tissue superposition (e.g. thin layer of blood masks underlying structures), intricate anatomical geometries, and lighting instability. These factors manifest as the mixed pixel and spectral variability problems, which remain the foremost challenges for hyperspectral imaging (HSI) in clinical applications.In this context, this paper presents a feasibility study leveraging Visible and Near-Infrared HSI combined with hyperspectral unmixing algorithms to address these complexities. Ex-vivo bovine samples, comprising key orthopedic tissues such as blood, ligaments, cartilage, bone, and fat, were imaged using HSI in a manner that replicates real operative challenges. Subsequently, six state-of-the-art unmixing algorithms selected for their ability to simultaneously resolve mixed pixels and mitigate spectral variability effects are evaluated. Through a comparative analysis, model-based unmixing algorithms demonstrated optimal performance in producing abundance maps that accurately quantify the proportion of distinct tissue types, even within a single pixel subject to variability perturbations. These algorithms successfully decouple environmental variability, such as shadowing, illumination shifts, and shape spectral deformations, from actual material proportions, preventing altered spectral signatures from confusing true abundance quantification.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261469566"},"PeriodicalIF":2.2,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148890881","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: Local Regression by Forming Matrix-Matched Calibration Sets Using Virtual Reality Sample Selection.","authors":"Hyrum J Redd, John H Kalivas","doi":"10.1177/00037028261483911","DOIUrl":"https://doi.org/10.1177/00037028261483911","url":null,"abstract":"<p><p>Linear regression for quantitative analysis commonly uses a calibration model based on a large global sample set spanning a substantial domain of calibration sample variance. Because of the large variance, determining accurate analyte amounts present in new target prediction samples is challenging. Instead, calibration samples closely matrix-matched to each target sample can be selected to generate localized linear regression models for accurate target sample analyte predictions. The difficulty with local regression in analytical chemistry is how to select calibration samples that bracket each target sample over small respective ranges of innate matrix-matched measured responses and analyte amounts. Recently developed was a robust autonomous local sample selection algorithm called local adaptive fusion regression (LAFR) that can realize the two-goaled sample selection. The method is based on the physicochemical responsive integrated similarity measure (PRISM) algorithm to compute hundreds of similarity measures between a target sample and a global library sample set. Depending on the library size, LAFR can require extensive time-consuming calculations and this paper compares LAFR to an easier more intuitive computer-human hybrid technique using virtual reality (VR) for local model sample selection. Recently explored with VR were successful applications to various chemometric data analysis scenarios relying on the user's lifetime problem-solving training and inherent pattern recognition skills. Like LAFR, these studies and this study use PRISM to compute sample similarity measures. These similarity values are further rendered into VR sample glyph features providing intuitive visualization of sample matrix effects, i.e., based on glyph appearances, the user selects matrix-matched calibration samples in VR localized to each target sample. Presented are partial least squares (PLS) prediction results from LAFR and VR selected calibration sets localized to fifteen target samples across three near infrared (NIR) data sets. By using VR, prediction errors are generally the same or better than LAFR without the lengthy LAFR calculations. Also presented is a discussion on the Rashomon effect supporting the substantial differences between the LAFR and VR regression vector shapes and magnitudes but the models predict similarly. Included in the discussion is the inability to interpret the models.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261483911"},"PeriodicalIF":2.2,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148890849","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: Amplitude-Ratio-Based Reconstruction of Surface Vibrational Spectra for Reducing Reorientation Artifacts in Preferential Adsorption Studies.","authors":"Mahsa Torkamanasadi, Dennis K Hore","doi":"10.1177/00037028261486548","DOIUrl":"https://doi.org/10.1177/00037028261486548","url":null,"abstract":"<p><p>Sum-frequency generation (SFG) spectroscopy is a powerful method for probing molecular composition and organization at interfaces. However, interpretation of SFG spectra in multicomponent systems is complicated because spectral intensities depend on both surface population and molecular orientation. This creates a challenge for analysis of the adsorbed population. Two-dimensional correlation spectroscopy (2D-COS) can aid in spectral interpretation, but molecular reorientation can distort spectral trends and lead to incorrect signs of the cross peaks. In this work, we investigate this problem first using model SFG spectra for a binary system in which the population and reorientation contributions are known, and in which the signal changes in a nonlinear manner with respect to the surface mole fraction. We describe an amplitude-ratio-based spectral reconstruction method where fitted vibrational mode amplitudes are used to calculate intra-component amplitude ratios relative to selected anchor modes. The corrected amplitudes are then used to reconstruct SFG spectra with reduced reorientation-induced artifacts. The reconstructed spectra show suppressed homospectral asynchronous features associated with intra-component reorientation and recover the expected heterospectral 2D-COS signs. The method is then applied to experimental SFG spectra of a binary mixture, further demonstrating that amplitude-ratio reconstruction provides a targeted approach for reducing reorientation artifacts and thereby enables population-based interpretation of SFG data.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261486548"},"PeriodicalIF":2.2,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148890915","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: Quantitative Prediction of Honey Peach (<i>Prunus persica L.</i>) Maturity Using Hyperspectral Imaging and Regression Generative Adversarial Network.","authors":"Cong Zhang, Hao Zhang, Cheng Xie, Linyun Xu, Hongping Zhou, Hongzhe Jiang","doi":"10.1177/00037028261486543","DOIUrl":"https://doi.org/10.1177/00037028261486543","url":null,"abstract":"<p><p>The honey peach (Prunus persica L.) is highly valued by consumers due to its distinctive flavor and nutritional richness. However, its quality is strongly influenced by the maturity stage, which directly affects the optimal harvest time and market value. To achieve rapid, non-destructive, and quantitative maturity assessment, hyperspectral imaging (HSI) was utilized to collect spectral data from samples across the visible-near-infrared (VIS-NIR) range. A comprehensive maturity index (CMI) was subsequently established by integrating key physicochemical parameters, including fruit weight, size, color, firmness, pH, moisture content, and soluble solids content (SSC). This index provided a holistic representation of maturity status. To address the limitation of a small sample size, a regression generative adversarial network (RGAN) was introduced. This model jointly generated spectral data and their corresponding CMI values. The generated samples exhibited high consistency with real samples in terms of spectral feature distribution, as visualized by t-distributed stochastic neighbor embedding (t-SNE), and CMI value distribution. Comparative evaluation of prediction models indicated that data augmentation with 800 generated samples enabled the convolutional neural network regression (CNNR) model to achieve optimal performance, with R_p of 0.952 and RMSEP of 0.187. This approach significantly improved predictive accuracy and generalization capability. In summary, the proposed method, which integrates HSI with RGAN for CMI prediction, allows for accurate quantification of honey peach maturity. And it offers an efficient and intelligent solution for maturity grading and quality control.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261486543"},"PeriodicalIF":2.2,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148890935","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: Time-Gated Raman Spectroscopic Characterization of Fluorescent Polyethylene Microplastics.","authors":"Korryn Narvaez, Courtney Ebert, Martin Zanazzi, Radu Boitor, Christopher Corden, Sara S Rocks, Ioan Notingher, Dustin W Shipp","doi":"10.1177/00037028261486537","DOIUrl":"https://doi.org/10.1177/00037028261486537","url":null,"abstract":"<p><p>Microplastics (MPs) have become increasingly common in nearly every natural environment. As their pervasiveness grows, so does the urgency to understand their abundance and origins. Raman spectroscopy has been used to identify MPs in natural environments. However, fluorescence from additives within MPs, other environmental matter, measurement substrates, or other factors can prevent MP identification. Polyethylene (PE) subtypes such as low-density, high-density, and ultra-high molecular weight polyethylene (LDPE, HDPE, and UHMWPE) have widely varying uses and origins (<i>e.g.</i> residential, industrial). In this work, we demonstrate a technique using time-correlated single photon counting (TCSPC) Raman spectroscopy to isolate the Raman signal of microplastics from competing fluorescence. Fluorescence suppression reduces spectral noise and improves quantitative spectral analysis. Decomposing Raman spectra using Voigt profiles enables quantification of PE crystallinity and estimation of its density. In artificially fluorescent and environmental samples, TCSPC Raman spectroscopy improved visualization of weak spectral features and calculation of PE crystallinity compared with continuous-wave (CW) Raman spectroscopy. For an environmental PE MP sample, CW Raman-derived crystallinity estimates often exceeded 100%. These non-physical values were attributed to a significant fluorescence background and low signal-to-noise ratio. In contrast, TCSPC measurements produced crystallinity estimates of 55-70% and 65-80% at two sampled locations on the MP. These results show the potential to quantitatively characterize MPs with TCSPC Raman spectroscopy. The ability to identify the subtype of PE MPs could assist in identifying the sources of microplastic pollution to protect natural environments.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261486537"},"PeriodicalIF":2.2,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148890843","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: Application of High-Frequency Ultrasound and Simultaneous Action of the High- and Low-Frequency Ultrasound in Sonoluminescence Spectroscopy.","authors":"Oleg I Yurchenko, Tatyana V Chernozhuk, Alexander N Baklanov, Larisa V Baklanova, Victor L Cherginets, Olexandr L Rebrov","doi":"10.1177/00037028261481610","DOIUrl":"https://doi.org/10.1177/00037028261481610","url":null,"abstract":"<p><p>Research on sonoluminescence spectroscopy was continued with a focus on determining the content of the main substance in natural underground brines and technological solutions with high salt concentrations (350-1000 g·dm⁻³) using high-frequency ultrasound (44-50 MHz) to initiate sonoluminescence. The influence of the initiating ultrasound frequency on the sonoluminescence intensity of CsCl, LiCl, and NaCl was determined. The maximum sonoluminescence intensity for alkali metal chlorides was achieved at an ultrasound frequency of 48-49 MHz and an intensity of 32 W·cm⁻².A method for determining Cs, Li, and Na content in highly concentrated technological solutions using high-frequency ultrasound to initiate sonoluminescence was developed. The method's validity was verified by analyzing the same samples using sonoluminescence spectroscopy with low- and mid-frequency ultrasound initiation.The simultaneous effect of high-frequency (45-50 MHz) and low-frequency (18-23 kHz) ultrasound in determining macroimpurities (KCl and LiCl) in NaCl brines using sonoluminescence spectroscopy was studied.When using the simultaneous action of high-frequency (44-50 MHz) and low-frequency ultrasound (18-23 kHz), the lower limit of determination of KCl and LiCl content in brines decreases by 12-15 times compared to the use of ultrahigh and low-frequency ultrasound and amounts to 0.007 and 0.008 g·dm^-3, respectively. The best results were obtained with the simultaneous effect of high-frequency ultrasound of 47-48 MHz with an intensity of 29-30 W cm^-2 and low-frequency ultrasound of 19-22 kHz with an intensity of 1.3-1.5 W cm^-2.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261481610"},"PeriodicalIF":2.2,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148787447","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: Reflection spectroscopy of bistable visual pigments in living butteries.","authors":"Primož Pirih","doi":"10.1177/00037028261481892","DOIUrl":"10.1177/00037028261481892","url":null,"abstract":"<p><p>Invertebrate vision relies on bistable visual pigments flipping upon photon absorption between rhodopsin and metarhodopsin states. In living butterflies, the UV-VIS absorption spectra of rhodopsin and metarhodopsin, respectively with 11-cis and all-trans isomers of 3-hydroxy-retinal (A3) chromophore, can be conveniently recorded from the eyeshine, the light reflected from the compound eye after passing twice through the light-guiding rhabdoms. * Here, a comprehensive pipeline for the analysis of eyeshine reflection spectra is presented. A microscope coupled with a broadband LED source and a microspectrometer was used to record the photorelaxations. Fitting temporal exponential relaxations to log-reflectance arrays yielded transient and baseline spectra that are analogous to absorbance difference and sum, respectively. Both types of spectra were subjected to singular value decomposition and to fitting of templated visual pigment absorption spectra. * The compound eye of the high brown fritillary <i>Fabriciana adippe</i> (Nympahlidae) was exposed to a series of second-long broadband light pulses, causing photorelaxations with time constants between 40 and 120 ms that led to 80% metarhodopsin in equilibrium. The transient and baseline spectra were fitted with pigment templates, estimating the alpha peak wavelength 547-552 nm for rhodopsin and 496-501 nm for metarhodopsin. The metarhodopsin to rhodopsin alpha peak absorbance ratio 1.25-1.35 is consistent with the isosbestic wavelength at 530 nm. The second isosbestic wavelength indicates that rhodopsin beta (UV) peak absorbs more strongly than metarhodopsin below 405 nm. * Baseline spectra, which were not explicitly analysed in previous studies, enable concatenation of exposures, monitor long-term changes of pigment, and enhance the estimation of beta peak parameters. * The method can be directly used in many butterflies and could be adapted to other insects, particularly fruitflies, facilitating studies of the relation between the visual pigment spectra and the opsin sequences. Spectroscopic results can be complemented with physiologically measured photoreceptor spectral sensitivity datasets and analysed with the same global fitting procedure.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028261481892"},"PeriodicalIF":2.2,"publicationDate":"2026-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148787462","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}