Applied Spectroscopy最新文献

{"title":"Surface-Enhanced Raman Spectroscopy (SERS) Substrates Based on Photonic Crystal Embedded Bi-Metallic Nanoparticles for Leptospiral DNA Detection.","authors":"Anis Athirah Abdul Razak, Liyana Shatar, Aima Ramli, Syara Kassim, Mohd Sabri Mohd Ghazali, Hui Yee Chee, Rozalina Zakaria, Mohd Adzir Mahdi, Fariza Hanim Suhailin","doi":"10.1177/00037028241303780","DOIUrl":"10.1177/00037028241303780","url":null,"abstract":"<p><p>Leptospirosis is an acute bacterial febrile disease affecting humans and animals in many tropical and subtropical countries. This work presents an optimization of surface-enhanced Raman spectroscopy (SERS) substrates to probe vibrational spectroscopic detail from <i>Leptospira</i> deoxyribonucleic acid (DNA). The pathogenic gene of LipL32 was used as a biomarker. The SERS substrates were based on a photonic crystal (PC) structure embedded with bi-metallic gold and silver nanoparticles (PC@AuAg NPs). The localized plasmonic resonance of AuAg NPs was coupled to the Raman modes of the target through SERS interaction. Prior to detection, the AuAg NPs were functionalized with chemical linkers to facilitate specific conjugation between metallic surfaces and DNA biomolecules. The immobilization and hybridization of probe DNA to their complementary target DNA (cDNA) created duplex formation for detection. The configuration was also tested with non-complementary DNA to verify detection specificity. Prominent SERS peaks were recorded, and the characteristic intensity decreased after cDNA hybridization due to less base interaction after complementary pairing. Distinct SERS behavior from the negative control test was also observed in non-complementary interaction. The configuration is highly attractive and can be potentially extended for sensitive and label-free detection of leptospiral DNA, paving the way for alternative diagnosis of leptospirosis.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"986-996"},"PeriodicalIF":2.2,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142833788","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":"Complex-Valued Chemometrics in Spectroscopy: Classical Least Squares Regression.","authors":"Thomas G Mayerhöfer, Oleksii Ilchenko, Andrii Kutsyk, Jürgen Pop","doi":"10.1177/00037028251343908","DOIUrl":"https://doi.org/10.1177/00037028251343908","url":null,"abstract":"<p><p>We present the first implementation of complex-valued classical least squares (CLS) regression in spectroscopy. Although the results indicate that complex-valued CLS does not outperform methods that utilize only the more suitable part of the complex refractive index spectra, it includes an error detection feature that enables a self-correction mechanism. This mechanism decreases the mean absolute error (MAE) to approximately 26% relative to using only the mid-infrared (MIR) absorption index (<i>k</i>) spectra for CLS, and to about 46% relative to using only the MIR refractive index (<i>n</i>) spectra of benzene-toluene mixtures. For benzene-cyclohexane mixtures, the MAE was reduced to approximately 75% relative to the <i>k</i> spectra and 58% relative to the <i>n</i> spectra. In contrast, for benzene-carbon tetrachloride (CCl₄) mixtures, i.e., a system that exhibits particularly large deviations from Beer's law, no improvement over the <i>n</i> spectra was observed; the <i>n</i>-based MAE was 81% relative to the <i>k</i> spectra. These percentages may further vary based on the complexity of the system, the spectral regions selected for CLS and the corresponding deviations from Beer's approximation.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251343908"},"PeriodicalIF":2.2,"publicationDate":"2025-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144141133","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":"Quantum Fourier Transform Infrared Spectroscopy: Evaluation, Benchmarking, and Prospects.","authors":"Paul Gattinger, Andreas W Schell, Sven Ramelow, Markus Brandstetter, Ivan Zorin","doi":"10.1177/00037028251340945","DOIUrl":"https://doi.org/10.1177/00037028251340945","url":null,"abstract":"<p><p>Sensing with undetected photons has enabled new, unconventional approaches to Fourier transform infrared spectroscopy (FT-IR). Leveraging properties of non-degenerate entangled photon pairs, mid-infrared (mid-IR) information can be accessed in the near-infrared (near-IR) spectral domain to perform mid-IR spectroscopy with silicon-based detection schemes. Here, we address practical aspects of vibrational spectroscopy with undetected photons using a quantum FT-IR (QFT-IR) implementation. The system operates in the spectral range from around 3000 cm^-1 to 2380 cm^-1 (detection at around 12 500 cm^-1) and possesses only 68 pW of mid-IR probing power for spectroscopic measurements with a power-dependence of the signal-to-noise ratio of 1.5 × 10⁵ mW^-1/2. We evaluate the system's short- and long-term stability and experimentally compare it to a commercial FT-IR instrument using Allan-Werle plots to benchmark our QFT-IR implementation's overall performance and stability. In addition, comparative qualitative spectroscopic measurements of polymer thin films are performed using the QFT-IR spectrometer and a commercial FT-IR with identical resolution and integration times. Our results show under which conditions QFT-IR can practically be competitive or potentially outperform conventional FT-IR technology.</p>","PeriodicalId":8253,"journal":{"name":"Applied Spectroscopy","volume":" ","pages":"37028251340945"},"PeriodicalIF":2.2,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144109641","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":"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}