Applied Spectroscopy最新文献

{"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}

{"title":"Prediction of Olivine Composition Under Limited Calibration Inputs: Comparative Study of Mid-Infrared Reflection, Raman Scattering, and Laser-Induced Plasma Spectroscopies.","authors":"Sergey G Pavlov, Iris Weber, Ute Böttger, Ulrich Schade, Jörg Fritz","doi":"10.1177/00037028241305162","DOIUrl":"10.1177/00037028241305162","url":null,"abstract":"<p><p>In situ optical analytical spectroscopies offer great geochemical insights due to their capability to resolve the chemical composition of regolith surfaces of rocky celestial bodies. The use of suitable calibration targets improves the precision of mineral determination, which is of critical importance for short-living, low-mobility landers, and enables, in special cases, determination of elemental composition. We investigate the capabilities of three space-relevant optical analytical techniques used for in situ mineralogical analysis, i.e., mid-infrared reflection, Raman light scattering, and laser-induced plasma spectroscopies, to predict the chemical composition of olivine under a limited calibration input, namely using two bulk samples of natural olivine, chemically close to the end-members of the mineral group. We determine the accuracy of the forsterite numbers obtained with each technique and discuss the choice of calibration methods applicable to limited in situ calibration input, which are summarized in recommendations for space instrumentation.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"767-783"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142891710","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":"Influence of Different Measuring Backgrounds on the Classification of Multilayer Polyolefin Films Using a Near-Infrared Handheld Spectrometer.","authors":"Hana Stipanovic, Patrick Arth, Gerald Koinig, Nikolai Kuhn, Jakob Lederer, Dominik Blasenbauer, Anna-Maria Lipp, Alexia Tischberger-Aldrian","doi":"10.1177/00037028241307034","DOIUrl":"10.1177/00037028241307034","url":null,"abstract":"<p><p>The low thickness of plastic films poses a challenge when using near-infrared (NIR) spectroscopy as it affects the spectral quality and classification. This research focuses on offering a solution to the challenge of classifying multilayer plastic film materials with a focus on polyolefin multilayer plastics. It presents the importance of spectral quality on accurate classification. The aim is to demonstrate the suitability of the handheld NIR spectrometer in classifying multilayer polyolefin films and assess the impact of various measuring backgrounds (white tile, Teflon, aluminum, copper, silver, and gold) on classification accuracy in the wavelength range of 1596-2396 nm. Metallic backgrounds have been found to enhance spectral quality and classification accuracy. The classification accuracy was consistently high, ranging from 96.55% to 100%, with aluminum and gold backgrounds yielding the best results in theoretical accuracy. In experimental classification, the accuracy reached 100% when any metallic backgrounds were used. Conversely, Teflon showed a theoretically high accuracy of 96.21% but only achieved an experimental accuracy of 72.2%. These findings suggest that using metallic backgrounds can improve the spectral quality and classification of plastics with low thickness (films) and complex material composition (multilayers).</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"816-828"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12053275/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142891708","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":"Advertising and Front Matter.","authors":"","doi":"10.1177/00037028251338081","DOIUrl":"https://doi.org/10.1177/00037028251338081","url":null,"abstract":"","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":"79 5","pages":"737-740"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143969379","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":"Integrated Optics Waveguides and Mesoporous Oxides for the Monitoring of Volatile Organic Compound Traces in the Mid-Infrared.","authors":"Felix Frank, Bettina Baumgartner, Mattias Verstuyft, Nuria Teigell Beneitez, Jeroen Missinne, Dries Van Thourhout, Gunther Roelkens, Bernhard Lendl","doi":"10.1177/00037028241300554","DOIUrl":"10.1177/00037028241300554","url":null,"abstract":"<p><p>Volatile organic compounds (VOCs) are an ever-growing hazard for health and environment due to their increased emissions and accumulation in the air. Quantum cascade laser-based infrared (QCL-IR) sensors hold significant promise for gas monitoring, thanks to their compact, rugged design, high laser intensity, and high molecule-specific detection capabilities within the mid-infrared spectrum's fingerprint region. In this work, tunable external cavity QCLs were complemented by an innovative germanium-on-silicon integrated optics waveguide sensing platform with integrated microlenses for efficient backside optical interfacing for the tunable laser spectrometer. The waveguide chip was coated with a mesoporous silica coating, thereby increasing the signal by adsorptive enhancement of VOCs while at the same time limiting water vapor interferences. Different least square fitting methods were explored to deconvolute the resulting spectra, showing subparts-per-million by volume (sub-ppmv) limits of detection and enrichment factors of up to 22 000 while keeping the footprint of the setup small (29 × 23 × 11 cm³). Finally, a use-case simulation for the continuous detection of VOCs in a process analytical technology environment confirmed the high potential of the technique for the monitoring of contaminants. By successfully demonstrating the use of photonic waveguides for the monitoring of VOCs, this work offers a promising avenue for the further development of fully integrated sensors on a chip.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"842-851"},"PeriodicalIF":2.2,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12053257/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142845702","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":"An Interlaboratory Study to Minimize Wavelength Calibration Uncertainty Due to Peak Fitting of Reference Material Spectra in Raman Spectroscopy.","authors":"Dirk Lellinger, James Thomson, Nicolas Coca-Lopez, Afroditi Ntziouni, Nikolaos Nikoloudakis, María Fernández-Álvarez, Nina Jeliazkova, Miguel A Bañares, Raquel Portela, Enrique Lozano Diz","doi":"10.1177/00037028251330654","DOIUrl":"https://doi.org/10.1177/00037028251330654","url":null,"abstract":"<p><p>Raman spectroscopy is a powerful characterization technique with increasing applications that would greatly benefit from data harmonization. Several standards deal with calibration in Raman spectroscopy, but no detailed procedure covers the complete calibration of an instrument, including both spectral axes, from reference material spectra generation to data processing. Moreover, the type of reference materials, the quality of the recorded spectra and the choice of the fitting functions are critical for obtaining precise and reliable reference data for calibration. This report describes the challenges and importance of peak fitting for Raman signal calibration based on an interlaboratory study with 10 different instruments. Spectra of neon emission, silicon, calcite, and polystyrene were fitted using common peak shapes, observing that Gaussian, Pearson IV, Voigt, and Voigt shapes are preferred for these materials, respectively. An analysis of the effect on the fitting of the signal-to-noise ratio (S/N) recommends a minimum value of 100 for a Raman peak if it should be used to calibrate a Raman instrument. Some factors that might affect the peak shape of the Raman signal, such as the physical and chemical properties of the sample, the nature of the electronic transitions, the instrument response and the spectral resolution are discussed. The results highlight the role of peak fitting analysis in improving the quality and reliability of Raman spectra calibration and, thus, enhancing data transfer and comparability, especially for handheld and portable Raman analyzers, as well as applications based on quantification, multivariate data analysis, and other complex processing steps.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251330654"},"PeriodicalIF":2.2,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143959689","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":"Prediction of Secondary Structure Content of Proteins Using Raman Spectroscopy and Self-Organizing Maps.","authors":"Marco Pinto Corujo, Pavel Michal, Dale Ang, Lindo Vivian, Nikola Chmel, Alison Rodger","doi":"10.1177/00037028251335051","DOIUrl":"https://doi.org/10.1177/00037028251335051","url":null,"abstract":"<p><p>Proteins are biomolecules with characteristic three-dimensional (3D) arrangements that render them different vital functions. In the last 20 years, there has been a growing interest in biopharmaceutical proteins, especially antibodies, due to their therapeutic application^. The functionality of a protein depends on the preservation of its native form, which under certain stressing conditions can undergo changes at different structural levels that cause them to lose their activity.¹ Although mass spectrometry is a powerful technique for primary structure determination, it often fails to give information at higher order levels. Like infrared (IR), Raman spectra are well known to contain bands (especially the amide I from 1625-1725cm^-1) that correlate with secondary structure (SS) content. However, unlike circular dichroism (CD), the most well-established technique for SS analysis, Raman spectroscopy allows a much wider ranges of optical density, making possible the analysis of highly concentrated samples with no prior dilution. Moreover, water is a weak scatterer below 3000 cm^-1, which confers Raman an advantage over IR for the analysis of complex aqueous pharmaceutical samples as the signal from water dominates the amide I region. The most traditional procedure to extract information on SS content is band-fitting. However, in most cases, we found the method to be ambiguous, limited by spectral noise and subjected to the judgment of the analyzer. Self-organizing maps (SOM) is a type of self-learning algorithm that organizes data in a two-dimensional (2D) space based on spectral similarity and class with no bias from the analyzer and very little effect from noise. In this work, a set of protein spectra with known SS content were collected in both solid and aqueous state with back-scatter Raman spectroscopy and used to train a SOM algorithm for SS prediction. The results were compared with those by partial least squares (PLS) regression, band-fitting, and X-ray data in the literature. The prediction errors observed by SOM were comparable to those by PLS and far from those obtained by band-fitting, proving Raman-SOM as viable alternative to the aforementioned methods.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251335051"},"PeriodicalIF":2.2,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143958924","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":"Enhanced Carbon Dioxide Uptake in Drilled Hollow Core Fibers for Raman Spectroscopy.","authors":"Brandon Demory, Jorge Arteaga, Sarah Sahota-Dhillon, Sayantani Ghosh, Tiziana Bond, Allan Chang","doi":"10.1177/00037028251329418","DOIUrl":"https://doi.org/10.1177/00037028251329418","url":null,"abstract":"<p><p>Fiber-based Raman spectroscopy enhances the Raman signal by maximizing the overlap of the optical field and the gas species. However, filling the hollow-core fiber (HCF) with gas requires time that is dependent on the fiber core diameter, fiber length, and pressure of the gas. At ambient pressure, the fiber gas uptake is driven by diffusion into the fiber ends, severely limiting the response time of the system. By laser drilling access holes to the core along the length of the fiber, the uptake time of the gas is reduced, improving the system response time. In this work, we study the carbon dioxide (CO₂) sensor dynamics based on Raman signal intensity generated in HCFs. The signal intensity versus gas concentration is characterized by controlling the CO₂ concentration in the surrounding environment of the fiber. Next, we characterize the gas uptake time in HCFs as a function of fiber length. Finally, we optimize the access hole configuration along the fiber, demonstrating reduced sensor uptake time by a factor of three.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251329418"},"PeriodicalIF":2.2,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143966191","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":"Advertising and Front Matter.","authors":"","doi":"10.1177/00037028251334196","DOIUrl":"https://doi.org/10.1177/00037028251334196","url":null,"abstract":"","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":"79 4","pages":"473-480"},"PeriodicalIF":2.2,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143960264","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}