Applied Spectroscopy最新文献

{"title":"Investigation of Thin Silicone Films on Opaque Solid Surfaces Using Coherent Raman Scattering Imaging.","authors":"Julian Naser, George Sarau, Jan Wrege, Silke Christiansen","doi":"10.1177/00037028251339495","DOIUrl":"https://doi.org/10.1177/00037028251339495","url":null,"abstract":"<p><p>The measurement of thin films with a thickness in the nanometer range is challenging because it requires extensive sample preparation, vacuum condition, long measurement times or using test inks that additionally contaminate the surface. The detection of those films is crucial for production processes that rely on a boundary layer to create a proper interface like adhesive bonding, coating, or lithography in various industries like automotive, solar, energy storage and semiconductor manufacturing. Consequently, there is a need for quick, reliable measurement techniques with high sensitivity to ensure the technical cleanliness of the opaque surface. In this paper the feasibility of epi-detection with coherent Raman scattering (CRS) Imaging is investigated on different substrate materials and demonstrated to be a method for fast scanning of large nontransparent surfaces including chemical fingerprinting of the substances atop. Therefore, various samples with low surface energy filmic contaminations from polysiloxanes are produced and investigated with CRS Imaging, a technique mostly applied to biological samples with the novel use demonstrated here for surface contamination monitoring in material sciences.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251339495"},"PeriodicalIF":2.2,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144109601","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-Angle Averaging Approach for Measuring the Coating Thickness on Thin Transparent Polymer Films.","authors":"Friederike Münch, Benedikt Hauer, Ingo Breunig, Daniel Carl","doi":"10.1177/00037028251334152","DOIUrl":"https://doi.org/10.1177/00037028251334152","url":null,"abstract":"<p><p>Polymer films with a thickness in the two-digit micrometer range are coated with nanometer-thin oxide layers in roll-to-roll coating systems. The coating improves the properties of the film, such as gas or water permeation. Maintaining a sufficiently large coating thickness is crucial to ensure its barrier function; thus, inline quality control of the thickness is indispensable. For this purpose, we have developed a sensing principle that addresses specific absorption bands of the coating via a reflection measurement in the infrared spectral range. However, for thin and weakly absorbing polymer substrates, light is reflected not only by the coating and the surface of the polymer. Partly it is also transmitted and reflected by the backside of the film, leading to interference effects that significantly affect the measurement signal. As industrial films vary in thickness by several percent and their exact values are unknown, determining the thickness of an oxide coating is hindered. In this paper, we demonstrate an approach for measuring coating thickness on such varying polymer films by averaging the interferences obtained at multiple angles of incidence. Calculations and measurements on industrial film samples indicate the effectiveness of our approach. It produces results with <math><mo>±</mo><mn>2</mn></math> nm precision and <math><mo>±</mo><mn>5</mn></math> nm accuracy for a thickness in the range of 5-100 nm. Furthermore, we discuss a possible implementation of this approach in an inline measurement system by fulfilling its requirements, for example, versatility and compactness.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251334152"},"PeriodicalIF":2.2,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144075614","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":"Characterization and Identification of Natural Amorphous Rocks Using Infrared, Raman, and Low-Frequency Raman Spectroscopy, Including the Application of Boson Peaks.","authors":"Kohei Tamura, Motohiro Tsuboi, Kuniyuki Furukawa, Ken-Ichi Akao, Harumi Sato, Yukihiro Ozaki","doi":"10.1177/00037028251333469","DOIUrl":"https://doi.org/10.1177/00037028251333469","url":null,"abstract":"<p><p>In this study, Raman spectra (3700-10 cm^-1) and attenuated total reflection infrared-far-infrared (ATR-IR/FIR) spectra (4000-50 cm^-1) including low-frequency region were measured for amorphous rocks, which were five types of obsidians whose formation ages and sources are different and pitchstone to clarify the differences in water content (free and bound water species), their Si-O bonds and possible linkage with a metal ion, and the mean atomic volume. In order to explore these points, we focused on infrared (IR) absorptions of hydroxyl (OH) groups that is observed in the 4000-3000 cm^-1 region, those of Si-O bond that is identified in the 1300-850 cm^-1 region and a Boson peak that appears in a low-frequency region of Raman spectra, respectively. IR absorption of Si-O stretching was detected for all samples and that of OH stretching and H-O-H bending was also detected in some rocks. Therefore, using IR spectroscopy was useful to discriminate each rock based on the water content and the environment of Si-O bonds. On the other hands, a Boson peak could be detected for the low-frequency region below 60 cm^-1 of Raman spectra, which appears in amorphous solids. This study is the first finding that the Raman shift of Boson peak was different among similar natural glassy rocks from multiple sources and it means that the mean atomic volume of samples was different. In addition, sharp bands of Raman scattering which came from inorganic substances such as feldspar helped to identify ingredients in samples. As a results, we made clear that using both IR and Raman including low-frequency regions is effective to identify the same types of natural amorphous rocks.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251333469"},"PeriodicalIF":2.2,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143955092","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":"Shortwave Infrared Hyperspectral Imaging to Detect Contaminants in the U.S. Food Supply.","authors":"David M Malakauskas, Hongjian Ding, Ben P Berman, Nap Thantu, Kevin L Karem, Victoria M Gammino","doi":"10.1177/00037028241301089","DOIUrl":"10.1177/00037028241301089","url":null,"abstract":"<p><p>The U.S. Food and Drug Administration (FDA) ensures the safety of the nation's food supply using sampling and laboratory analysis of imported and domestic foods. Accurate detection and identification of extraneous filth elements in inspected food samples is critical in producing evidence for regulatory decision-making. As part of ongoing efforts to increase the efficiency and accuracy of data collection, to better inform regulatory decision-making, scientists at the FDA have been exploring the application of emerging imaging technologies. To this end, we tested the ability of shortwave infrared (SWIR) hyperspectral image analysis to simultaneously detect and identify filth elements from a variety of chemically digested single- and multiple-ingredient food matrices. We tested five stored-product beetle species on a background of four different food matrix types. Our analyses successfully detected whole beetles and fragments as small as 0.65 mm in 95% of samples. All beetle species tested were accurately detected from the background matrices, and initial classification results show identification to genus. Our results show that SWIR spectral image analysis is a very promising technology for application in the detection and identification of filth elements in food products in a regulatory context and further development has the potential to increase analytical efficiency at FDA regulatory labs.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"872-878"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778721","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":"Alternating and Modified Alternating Least Squares Applied to Raman Spectra of Finished Gasolines.","authors":"Collin G White, Thomas M Hancewicz, Ayuba Fasasi, Junior Wright, Barry K Lavine","doi":"10.1177/00037028241292649","DOIUrl":"10.1177/00037028241292649","url":null,"abstract":"<p><p>Extraction of components from individual refinery streams (e.g., reformates and alkylates) in finished gasoline was undertaken using Raman spectroscopy to characterize the chemical content of the finished product. Modified alternating least squares (MALS) was used for separating Raman spectroscopic data sets of the finished product into its pure individual components. The advantages of MALS over alternating least squares (ALS) for multicomponent resolution are highlighted in this study using three Raman spectroscopic data sets which provide a suitable benchmark for comparing the performance of these two methods. MALS is superior to ALS in terms of accuracy and can better resolve components than ALS, and it is also more robust toward collinear data. Finally, components near the noise level usually cannot be extracted by ALS because of instability when inverting the covariance structure which inflates the noise present in the data. However, these same components can be extracted by MALS due to the stabilization of the least squares regression with respect to the matrix inversion using modified techniques from ridge regression.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"808-815"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142602885","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":"Characterization of Orthophosphate and Orthovanadate in Aqueous Solution Using Polarized Raman Spectroscopy.","authors":"Wolfram Rudolph","doi":"10.1177/00037028241275107","DOIUrl":"10.1177/00037028241275107","url":null,"abstract":"<p><p>Polarized Raman spectroscopy was used to analyze aqueous solutions of sodium orthophosphate and orthovanadate over a wide concentration range (0.00891-0.702 mol/L) at 23 °C. The isotropic scattering profiles were obtained by measuring polarized Raman scattering spectra. Furthermore, R-normalized spectra were calculated and presented. The tetrahedral ions, VO₄^3-(aq) and PO₄^3-(aq), demand four Raman active bands which have been subsequently characterized and assigned. For the PO₄^3-(aq) ion, the deformation modes ν₂(e) and ν₄(f₂) appear at 415 and 557 cm^-1, and these modes are depolarized. In the P-O stretching region, the strongest Raman band appears at 936.5 cm^-1, which is totally polarized with a depolarization ratio (ρ-value) of 0.002. The broad and depolarized mode at 1010 cm^-1 constitutes the antisymmetric stretching band ν₃(f₂). The Raman spectrum of VO₄^3- shows two depolarized deformation modes ν₂(e) and ν₄(f₂) at 327 and 345.6 cm^-1, which are severely overlapped. These bands are very weak. The strongest band in the Raman spectrum of VO₄^3-(aq) is the symmetric stretching mode ν₁(a₁) at 820.2 cm^-1 which is totally polarized with a ρ-value at 0.004. The depolarized antisymmetric stretching mode ν₃(f₂) appeared at 785 cm^-1 as a broad and weak band. Both anions are strongly hydrated and showed extensive hydrolysis in an aqueous solution. Orthovanadate is a much stronger base than orthophosphate in aqueous solution. Therefore, a large amount of NaOH was used to suppress the hydrolysis of VO₄^3-(aq) sufficiently, so, it was possible to characterize the VO₄^3- modes. Quantitative Raman spectroscopy was applied to follow the hydrolysis of PO₄^3- over a wide concentration range from 0.00891 to 0.592 mol/L. The hydrolysis data allowed the calculation of the p<i>K</i>_a3 value for H₃PO₄ to be 12.330 ± 0.02 (25 °C). The hydrolysis of the VO₄^3- ion is ∼21 times larger than that of the PO₄^3-. The p<i>K</i>_a3 value for H₃VO₄ is estimated to be 13.65 ± 0.1 (25 °C).</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"829-841"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142139139","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":"Theoretical Calculation and Simulation of Peak Distortion of Absorption Spectra of Complex Mixtures.","authors":"Rui Cheng, Thomas G Mayerhöfer, Johannes Kiefer","doi":"10.1177/00037028241297179","DOIUrl":"10.1177/00037028241297179","url":null,"abstract":"<p><p>Attenuated total reflection (ATR) spectroscopy in infrared is a standard tool used in most analytical labs, as it allows a rapid chemical analysis with virtually no sample preparation. However, when the sample contains materials with a high refractive index, special care must be taken as the resulting data may be severely biased. This article reports a theoretical approach to correcting distorted ATR spectra. Starting from Snell's law, Lorenz model and Fresnel's equations are combined to obtain the complex relationship between optical constants. With calculating the real and imaginary parts, that is, <math><mi>n</mi><mo>(</mo><mi>ν</mi><mo>)</mo></math> and <math><mi>k</mi><mo>(</mo><mi>ν</mi><mo>)</mo></math>, respectively, of the complex refractive index from the absorption spectrum, a model for mixtures comprising of a liquid and a solid is established. The effects of distortion and potential misinterpretation of the data are discussed. Proof-of-concept experiments with mixtures of carbonaceous materials and toluene confirm the theoretically predicted observations.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"852-861"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12053103/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142799264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectroscopic Study of Micro-/Nano-Hydroxyapatite Polymer Composites Modified with Carbon Nanofibers.","authors":"Anna Kołodziej, Małgorzata Rachwał, Elżbieta Długoń, Magdalena Ziąbka, Aleksandra Wesełucha-Birczyńska","doi":"10.1177/00037028251316290","DOIUrl":"10.1177/00037028251316290","url":null,"abstract":"<p><p>Nowadays, novel biomaterials are under intense research because they are part of promising therapies for the treatment of age-related diseases such as osteoporosis and bone defects. In the presented study, composites of poly(ε-caprolactone) (PCL), micro and nano hydroxyapatite (µ-HAp and n-HAp) and carbon nanofibers (CNFs) were prepared. The influence of additives on polymeric matrix was analyzed using scanning electron microscopy (SEM), Raman micro-spectroscopy, Raman mapping, and two-dimensional correlation spectroscopy (2D-COS). The bioactivity in vitro was evaluated by a 21-day incubation of prepared membranes in simulated body fluid (SBF). It was concluded that additives can behave as crystallization nuclei of PCL, but they are also located across the entire surface of PCL spherulites, not only in the center. With an increasing content of HAp additives, polymeric spherulites become smaller. The type of HAp (µ-HAp or n-HAp) influences the PCL matrix differently, as confirmed by 2D-COS. The component whose addition leads to most significant changes in the polymer is CNFs; polymeric spherulites are small to the extent that they are not distinguishable, and the overall amorphousness of the polymer is the highest among all tested materials, as is its hydrophobicity. The bioactivity test indicated that the membrane with the greatest potential for use as a biomaterial in bone tissue engineering is one consisting of n-HAp (15 wt%) and CNFs, as very uniform coverage of the produced apatite was observed on the surface of this membrane after incubation in SBF.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"741-755"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143432369","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":"Comparison of a Quantum Cascade Laser and an Interband Cascade Laser for the Detection of Stable Carbon Dioxide Isotopes Using Tunable Laser Absorption Spectroscopy.","authors":"Ponkanok Nitzsche, Cem Dinc, Jens Goldschmidt, Leonard Nitzsche, Jürgen Wöllenstein, Katrin Schmitt","doi":"10.1177/00037028241291157","DOIUrl":"10.1177/00037028241291157","url":null,"abstract":"<p><p>Quantum cascade lasers (QCLs) and interband cascade lasers (ICLs) are widely used as light sources in tunable laser absorption spectroscopy because they emit in the mid-infrared region where many strong and characteristic absorption bands are present. In this paper, we compare the performance of these lasers emitting at about 2310.1 cm^-1 to determine an optimal light source for detecting isotopic ratios of carbon dioxide (CO₂). Our results show that the QCL has a higher relative intensity noise of up to 15 dBc/Hz compared to the ICL over the entire measured frequency range. In addition, it has a higher frequency fluctuation. However, the maximum tuning range of the QCL is up to 5.2 cm^-1 compared to up to 3.8 cm^-1 for the ICL. Both lasers lose more than half of their tuning range when the tuning rate is increased to 10 kHz. When measuring the isotope ratio of CO₂, an uncertainty in the <math><msup><mi>δ</mi><mn>13</mn></msup></math> value of <math><msubsup><mi>σ</mi><mrow><mrow><mn>13</mn><mi>C</mi><mo>,</mo><mi>min</mi></mrow></mrow><mrow><mrow><mi>ICL</mi></mrow></mrow></msubsup><mo>=</mo><mn>0.17</mn></math>‰ was achieved with the ICL and of <math><msubsup><mi>σ</mi><mrow><mrow><mn>13</mn><mi>C</mi><mo>,</mo><mi>min</mi></mrow></mrow><mrow><mrow><mi>QCL</mi></mrow></mrow></msubsup><mo>=</mo><mn>0.42</mn></math>‰ with the QCL, both at an integration time of 0.2 s. In summary, the QCL is more appropriate for applications that require a larger spectral tuning range, such as the measurement of a complex gas mixture, while the ICL has an excellent signal-to-noise ratio and is therefore better suited for applications that require higher precision.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"862-871"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142613925","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":"Rapid-Scan Fourier Transform Infrared Difference Spectroscopy with Two-Dimensional Correlation Analysis to Show the Build-Up of Light-Adapted States in Bacterial Photosynthetic Reaction Centers.","authors":"Alberto Mezzetti, Marco Malferrari, Giovanni Venturoli, Francesco Francia, Winfried Leibl, Isao Noda","doi":"10.1177/00037028241304806","DOIUrl":"10.1177/00037028241304806","url":null,"abstract":"<p><p>Time-resolved, rapid-scan Fourier transform infrared (FT-IR) difference spectra have been recorded upon illumination on photosynthetic reaction centers (RCs) from <i>Rhodobacter sphaeroides</i> under fixed hydration conditions (relative humidity = 76%). Two different illumination schemes were adopted. Whereas the use of a laser flash (duration: 7 ns) made it possible to follow the kinetics of recombination of the light-induced state P⁺Q_A^- to the neutral state PQ_A, the use of a 20.5 s continuous light from a lamp made it possible to follow both the build-up of a steady-state P⁺Q_A^- population and its decay to PQ_A. Comparison between P⁺Q_A^-/PQ_A FT-IR difference spectra obtained under (or 650 ms after) continuous illumination and obtained after one laser flash show small but meaningful differences, reflecting structural changes in the light-adapted state produced by the 20.5 s period of illumination. These differences are strikingly similar to those observed when comparing FT-IR difference spectra reflecting charge separation in photosystem II in light-adapted states and non-light-adapted states (c.f. Sipka et al., \"Light-Adapted Charge-Separated State of Photosystem II: Structural and Functional Dynamics of the Closed Reaction Center\". Plant Cell. 2021. 33(4): 1286-1302). Two-dimensional correlation spectroscopy analysis revealed that in all the observed series of time-resolved FT-IR difference spectra (under illumination, after illumination, and after a laser flash), marker bands at 1749, 1716, and 1668 cm^-1 all evolve synchronously, demonstrating that electron transfer reactions and protein backbone response (at least the one reflected by the 1668 cm^-1 band) are strongly correlated. Conversely, for spectra under and after continuous illumination, many asynchronicities are observed for (still unassigned) bands throughout the whole 1740-1200 cm^-1 region, reflecting a more complicated molecular scenario in the RC upon build-up of the light-adapted state and during its relaxation to the resting neutral state.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"756-766"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143027828","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}