Applied Spectroscopy最新文献

{"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":"Machine Learning Techniques for Geochemical Analysis Using Laser-Induced Breakdown Spectroscopy.","authors":"Shamaila Akbar, M Inzmam Razzaq, Nasar Ahmed, Kamran Abbas, M Rafique, M Aslam Baig, Rinda Hedwig, Zahid Farooq","doi":"10.1177/00037028251334151","DOIUrl":"https://doi.org/10.1177/00037028251334151","url":null,"abstract":"<p><p>In the present work, appropriate machine learning techniques coupled with LIBS have been proposed for the effective classification of multielement rock samples. To obtain the best classification efficiency most suitable emission lines were selected. Plasma on the surface of seventeen rock samples was generated using a 532  nm Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, and optical emission spectra were collected via an Avantes spectrometer. Well-isolated signature emission lines corresponding to detected elements (Ca, Mg, Na, K, Fe, Ba, Sr, Si, Al, and Li) were chosen as input for the machine learning algorithms. Three machine learning techniques, including analysis of variance (ANOVA), principal component analysis (PCA), and PCA coupled with standard normal variate (SVM), were utilized on normalized intensities of selected spectral lines of detected elements. ANOVA testing on the selected lines was employed to assess the normality and suitability of data for further machine learning techniques. The combination of laser-induced breakdown spectroscopy (LIBS) with PCA enabled a comprehensive classification of rock samples. The linearity and efficiency of PCA were enhanced by utilizing the support vector machine (SVM), resulting in the accurate classification of rock samples. This study demonstrates that to assess the effective classification of multielement rock samples the appropriate emission lines and machine learning techniques are crucial. Using this methodology results become more reliable as compared to conventional machine learning techniques.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251334151"},"PeriodicalIF":2.2,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143961140","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":"Enzyme Dynamics in Attoliter-Volume Electrochemical Zero-Mode Waveguides with On-Demand In Situ Hydrogen Peroxide Delivery and Consumption.","authors":"Jarek Metro, Julius Reitemeier, Paul W Bohn","doi":"10.1177/00037028251329956","DOIUrl":"https://doi.org/10.1177/00037028251329956","url":null,"abstract":"<p><p>Physiological systems are not at equilibrium and undergo time-dependent fluctuations, making it challenging to relate in vitro studies to in vivo biomolecular behavior. To bridge this gap, enzyme dynamics can be studied in the presence of controlled perturbations that recapitulate the intracellular environment. Here, we report an approach to the study of reactive oxygen species (ROS) based on the in situ manipulation of hydrogen peroxide (H₂O₂) levels in functionalized nanopore-based electrochemical zero-mode waveguide (EZMW) arrays, with each nanopore presenting small numbers of immobilized horseradish peroxidase (HRP) enzyme molecules. H₂O₂ is generated or consumed within the attoliter volume of the EZMW nanopores by poising an embedded ring electrode to suitable potentials, and the resulting effect on apparent turnover of HRP under non-equilibrium conditions is monitored using the enzymatically accelerated conversion of the non-fluorescent probe Amplex Red to fluorescent resorufin. A Nafion membrane is placed on the top surface of the EZMW array, providing a cation permselective barrier to transport in, or out, of the EZMW nanopores, thereby improving the sensitivity of the experiment by sequestering enzymatically generated resorufin in the attoliter volume of the EZMW nanopores. By fabricating arrays presenting 441 individual reaction volumes in parallel, distinct changes in population dynamics in the presence of in situ H₂O₂ generation or consumption are characterized with respect to temporal evolution and magnitude of the H₂O₂ aliquot delivered. This approach presents a promising avenue for studying biomolecular reactions in spatiotemporally controlled chemical environments that can mimic the non-equilibrium conditions encountered in vivo.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251329956"},"PeriodicalIF":2.2,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143960263","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":"Stoichiometric Control of Bismaleimide Conjugation of DNA to Silica Surfaces Through Quantitative Fluorescence Analysis of Thiolated DNA.","authors":"Grant J Myres, Jay P Kitt, Joel M Harris","doi":"10.1177/00037028251332617","DOIUrl":"https://doi.org/10.1177/00037028251332617","url":null,"abstract":"<p><p>Surface immobilization of DNA for biosensing or separations applications requires covalent attachment chemistry that is efficient, reproducible, and stable. In this work, an approach to link thiol-functionalized DNA to thiol-modified silica surfaces using N,N'-1,4-phenylene-bismaleimide is optimized by developing an efficient, one-pot synthesis of the maleimide-conjugated DNA followed by its immediate reaction with thiolated porous silica particles. The methodology takes advantage of a Michael addition reaction that couples a phenyl-bismaleimide cross-linking reagent and thiol-modified DNA to form a monomeric DNA-maleimide conjugate. The 1:1 stoichiometry of this reaction must be carefully controlled to avoid excess thiol-DNA, which generates unreactive bismaleimide-linked DNA dimers, or excess bismaleimide, which competes with the DNA-maleimide conjugate for reaction with the thiolated silica surface. To achieve control over the reaction forming the DNA conjugate, we adapt a fluorescence assay for free-thiols using 7-diethylamino-3-(4-maleimidophenyl)-4-methyl-coumarin (CPM) to determine the concentration of thiol-modified DNA that emerges from its synthesis, disulfide labeling, reduction to a thiol, and purification. The fluorescence response of the CPM reagent was calibrated using reduced glutathione as a standard, which allowed determination of the concentrations of thiolated-DNA and control over the stoichiometry of its reaction with a bismaleimide linker. The maleimide-conjugated DNA product thus formed was then reacted with thiolated-silica in order to bind the DNA to the internal surfaces of porous silica, whose surface populations were determined in individual particles by confocal Raman microscopy. Self-modeling curve resolution of the Raman spectra of surface-bound molecules validated the efficiency of the bismaleimide:thiolated DNA reaction, which provided stoichiometric control over formation of the monomeric DNA-maleimide conjugate and its optimized reaction with thiolated-silica surfaces.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251332617"},"PeriodicalIF":2.2,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143952566","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":"Determination of Laser-Induced Fluorescence Lifetimes Excited by Pulses of Comparable Duration.","authors":"Lize Coetzee, Esa Jaatinen","doi":"10.1177/00037028251332975","DOIUrl":"https://doi.org/10.1177/00037028251332975","url":null,"abstract":"<p><p>This paper presents a novel analytical technique for evaluating fluorescence lifetimes excited by a nanosecond pulsed laser using a linearized rate equation approach that accounts for the incident pulse temporal distribution, an equivalent instrument response function, and non-exponential fluorescence decay which limits the application of traditional fluorescence lifetime techniques in stand-off applications. The approach is applied to model the fluorescence of a variety of pharmaceutical powders and phosphorescing samples exhibiting non-exponential decay and compared to results obtained with the maximum entropy method. Fluorescence lifetimes are found to be 3-5  ns, typical for organic fluorescent powders, and phosphorescence lifetimes were on the order of hundreds of nanoseconds. The approach also shows potential for determining the composition of mixed samples and can be readily extended to model increasingly complex scenarios with additional fluorescing or phosphorescing components.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251332975"},"PeriodicalIF":2.2,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143955096","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":"Application of Laser Spectroscopy and Machine Learning for Diagnostics of Uncontrolled Type 2 Diabetes.","authors":"Imran Rehan, Kamran Rehan, Sabiha Sultana, Mujeeb Ur Rehman","doi":"10.1177/00037028251334383","DOIUrl":"https://doi.org/10.1177/00037028251334383","url":null,"abstract":"<p><p>Diabetes, a chronic metabolic disorder affecting millions worldwide, presents a persistent need for reliable and non-invasive diagnostic techniques. Here, we suggest a highly effective approach for differentiating between fingernails from diabetic individuals and those from healthy controls using laser-induced breakdown spectroscopy (LIBS). The excitation source employed was a Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser emitting light with a wavelength of 1064  nm. The initial differentiation between individuals with and without diabetes was achieved by applying principal component analysis (PCA) to LIBS spectral data, which was then incorporated into a novel machine-learning model. The classification model designed for a non-invasive system included random forest (RF), an extreme learning machine (ELM) classifier, and a hybrid classification model incorporating cross-validation techniques to evaluate the outcomes. The algorithm analyses the complete spectrum of both healthy and diseased samples, categorizing them according to differences in LIBS spectral intensity. The classification performance of the model was assessed using a <i>k</i>-fold cross-validation method. Seven parameters, i.e., specificity, sensitivity, area under curve (AUC), accuracy, precision, recall, and F-score, were used to evaluate the model's overall performance. The findings affirmed that the suggested non-invasive model could predict diabetic diseases with an accuracy of 95%.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251334383"},"PeriodicalIF":2.2,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143960554","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":"Perspective on the Capacity of the Rashomon Effect in Multivariate Data Analysis.","authors":"John H Kalivas","doi":"10.1177/00037028251330324","DOIUrl":"https://doi.org/10.1177/00037028251330324","url":null,"abstract":"<p><p>Presented is a perspective proposing to expand some fragmented spectroscopic modeling and data analysis practices by incorporating multivariate ideologies. For example, through recognizing the theory of analytic chemistry (TAC) by Booksh and Kowalski, it is common to use the multivariate processes (higher orders) of multiple wavelengths for regression and prediction or classification, fusing multiple instruments, or applying multi-way methods such as parallel factor analysis (PARAFAC). Each wavelength, instrument, PARAFAC order deliver different views of underlying sample-wise full matrix effects adding more information per dimension for improved data characterizations. Reasoned here is that model selection, figures of merit, and sample similarity assessments for model prediction reliability, outlier detection, or classification purposes can meaningfully progress by recognizing the multivariate principles of the TAC and additionally, the importance of the Rashomon effect. Applying the Rashomon effect with the TAC removes conventional fragmented data analysis approaches bringing a more wholeness to data analysis. Included in this discussion is that due to the Rashomon effect, interpretation of spectral models is not reasonable. For an uncommon view of these concepts, the perspective ends with drawing parallels between sample-wise matrix effects and the concepts explicate and implicate orders from physicist David Bohm's depiction of our physical and conscious world and universe. It is hoped that this perspective tempts reflection in your particular area of spectroscopy.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251330324"},"PeriodicalIF":2.2,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143961144","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}