Vibrational Spectroscopy最新文献

{"title":"A variable selection method based on multicollinearity reduction for food origin traceability identification","authors":"Lu Tian ,&nbsp;Yankun Li ,&nbsp;Mengsha Zhang","doi":"10.1016/j.vibspec.2025.103804","DOIUrl":"10.1016/j.vibspec.2025.103804","url":null,"abstract":"<div><div>In spectral modelling analysis, multicollinearity problems among the spectral variables are prevalent, which may reduce the accuracy of the analysis result. To reduce the effect of multicollinearity between variables in classification analysis, a new strategy of variable selection named as multicollinearity reduction-based variable selection (MR-based VS) is proposed. Characteristic variables were selected based on inter-class significant difference and intra-class correlation evaluation, which reduced data multicollinearity and ensured the selected variables were more relevant to the categories. It was combined with supervised pattern recognition methods of least squares discrimination analysis (PLS-DA) and uncorrelated linear discriminant analysis (ULDA) for the identification of the red wine and olive oil from different geographical origins. The results show that compared with the full-spectrum model and the traditional successive projection algorithm (SPA) variable screening model, the MR-based VS strategy reduces the multicollinearity between variables while ensuring the maximum difference among the different classes, as a result, it obtained the superior classification results. Therefore, MR-based VS can effectively extract categorical features, eliminate redundant information, and improve model interpretability, which shows potential for enhancing the ability of the spectral qualitative analysis model in different fields.</div></div>","PeriodicalId":23656,"journal":{"name":"Vibrational Spectroscopy","volume":"138 ","pages":"Article 103804"},"PeriodicalIF":2.7,"publicationDate":"2025-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143830295","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":"Ensure the authenticity of antibiotic vials: An independent testing protocol using attenuated total reflection infrared spectroscopy and Raman spectroscopy","authors":"Ahmed M. Ibrahim,&nbsp;Lamiaa A. Hassan","doi":"10.1016/j.vibspec.2025.103803","DOIUrl":"10.1016/j.vibspec.2025.103803","url":null,"abstract":"<div><div>The burgeoning global pharmaceutical market has witnessed a concurrent surge in counterfeit drug proliferation, particularly in developing countries. Counterfeit antibiotics pose a significant threat to public health, potentially leading to treatment failures, antibiotic resistance, and even fatalities. This study presents an innovative independent testing protocol employing Raman spectroscopy and attenuated total reflection infrared spectroscopy (ATR-IR) for the rapid and accurate detection of counterfeit antibiotic vials. These rapid, eco-friendly, and non-destructive techniques enable the acquisition of critical information about the analyzed samples. However, while ATR-IR preserves the chemical composition and structural integrity of the sample, physical contact with the ATR crystal may prevent complete sample recovery. The combination of ATR-IR and Raman spectroscopy leverages their distinct analytical principles ATR-IR detecting polar asymmetric vibrations (dipole moment variations) and Raman identifying symmetric vibrations (polarizability changes) to provide a robust and reliable solution for detecting counterfeit antibiotics. Both Raman spectroscopy and ATR-IR demonstrated exceptional precision and specificity of 100 %, underscoring the model remarkable reliability in counterfeit classification (all counterfeit samples were successfully rejected). Fluorescence backgrounds in Raman spectroscopy were mitigated by employing a 1064 nm laser wavelength, enhancing its applicability for complex matrices. Our Independent Testing Protocol presents a promising solution to the complex issue of counterfeit antibiotic vial detection. By synergizing the strengths of Raman spectroscopy and ATR-IR, we achieve a comprehensive and reliable assessment of antibiotic vials, thereby contributing to patient safety and public health protection.</div></div>","PeriodicalId":23656,"journal":{"name":"Vibrational Spectroscopy","volume":"138 ","pages":"Article 103803"},"PeriodicalIF":2.7,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799311","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":"Raman signature of partial zircon to scheelite-type phase conversion in GdVO4 nanosystem due to structural disordering induced by Eu3+ inclusions","authors":"Aftab Ansari ,&nbsp;D. Mohanta","doi":"10.1016/j.vibspec.2025.103802","DOIUrl":"10.1016/j.vibspec.2025.103802","url":null,"abstract":"<div><div>This work reports Raman analysis of <em>zircon</em>-to-<em>scheelite</em> partial phase conversion encountered in GdVO₄ nanosystem with Eu³⁺ around permissible substitutional doping. To be specific, among the Raman modes featured, the <em>A</em>_1g mode is attributed to O-V-O vibration while <em>B</em>_2 g represents the translatory vibrational mode (∼258 cm⁻¹) attributed to the Eu–O stretching. The intense high-frequency mode, <em>ν</em>₂ = 880 cm^–1 would describe stretching internal vibration in the tetrahedral [VO₄]^3- anionic group for an ideal <em>zircon-</em>type conformation with tetragonal symmetry. Importantly, at room temperature Raman studies of GdVO₄ nanosystem, the overlap of two Raman active modes namely, <em>A</em>_1g (scissoring) and <em>B</em>_2g (twisting) characterize <em>scheelite</em>-type characteristics in the nanosystem under study. Incorporation of Eu³⁺ in the system resulted in enhancing the intensity of the <em>scheelite</em>-type characteristics due to possible localized phase transition around Eu³⁺ sites in the matrix. The observed <em>scheelite</em>-type signal enhancement and consequently partial <em>zircon</em> lattice to <em>scheelite</em> lattice conversion due to inclusion of Eu³⁺ doping (1–7 %) has been highlighted and analyzed emphasizing manifested modes in detail.</div></div>","PeriodicalId":23656,"journal":{"name":"Vibrational Spectroscopy","volume":"138 ","pages":"Article 103802"},"PeriodicalIF":2.7,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792781","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":"Pharmaceutical evaluation of magnesium oxide fine granule formulation for conversion to magnesium hydroxide owing to humidification by near-infrared spectroscopy","authors":"Yoshihisa Yamamoto ,&nbsp;Mayo Mitani ,&nbsp;Toshiro Fukami ,&nbsp;Tatsuo Koide","doi":"10.1016/j.vibspec.2025.103801","DOIUrl":"10.1016/j.vibspec.2025.103801","url":null,"abstract":"<div><div>In this study, we evaluated the changes in near-infrared (NIR) spectra of heavy MgO (100 % MgO; H_MgO) fine granules formulations when stored under humidified conditions. The H_MgO formulations are often mixed with other powdered formulations in clinical practice. In all H_MgO formulations, the peaks at approximately 7350 cm⁻¹ and 7150 cm⁻¹ increased, whereas the peak at approximately 7300 cm⁻¹ decreased depending on the storage period under humidified conditions. Furthermore, slight enhancement of the peaks around 7250 cm⁻¹ and 7200 cm⁻¹ was also observed. These peak changes are attributed to the three-dimensional structure of magnesium hydroxide (Mg(OH)₂) produced by humidification. Subsequently, we evaluated the changes in the NIR spectrum of H_MgO after mixing with 10 % water. The time required for the peak change to appear was shorter than that for storage under humidified conditions. Furthermore, the peaks around 7350 cm⁻¹ , 7250 cm⁻¹ , and 7150 cm⁻¹ were clearly enhanced, and the peak around 7300 cm⁻¹ disappeared immediately after the addition of water. These results suggest that although Mg(OH)₂ is produced when H_MgO is mixed with water, the rate and mechanism of production differ from those observed under humidified storage. The presence of Mg(OH)₂ generated by humidified storage or by mixing with water may affect the stability and water solubility of concomitant pharmaceutical formulations that are sensitive to an alkaline environment. The findings of this study provide useful insights from both fundamental and medical perspectives, and they suggest that NIR spectroscopy, which allows rapid and non-destructive measurements, is effective for these evaluations.</div></div>","PeriodicalId":23656,"journal":{"name":"Vibrational Spectroscopy","volume":"138 ","pages":"Article 103801"},"PeriodicalIF":2.7,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747172","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":"Serum Raman Spectroscopy – An exploratory study for detection of chronic obstructive pulmonary disease","authors":"Gautam Sharma ,&nbsp;Priyanka Jadhav ,&nbsp;Sampurno Banerjee ,&nbsp;Debarghya Pratim Gupta ,&nbsp;Mahesh Padukudru Anand ,&nbsp;Koustav Ganguly ,&nbsp;Sanjeeva Srivastava ,&nbsp;C. Murali Krishna","doi":"10.1016/j.vibspec.2025.103798","DOIUrl":"10.1016/j.vibspec.2025.103798","url":null,"abstract":"<div><div>Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death worldwide, but our understanding of its pathophysiology is limited. COPD is a debilitating pathology distinguished by diminished pulmonary function and a rapid and persistent decline in overall well-being. Early diagnosis is critical in creating strategies for reducing risk factors and managing COPD consequences. The present study utilised Raman Spectroscopy (RS) to examine serum samples collected from three distinct male cohorts: healthy subjects, asymptomatic smokers, and patients diagnosed with COPD, with a sample size of 10 individuals per group. Given that biochemical alterations take place prior to morphological alterations, RS may be a useful technique for early diagnosis of any pathology. Spectral comparisons revealed a drop in lipid contents and an increase in protein content in the COPD group when compared to the healthy subjects (NR) and asymptomatic smokers (SN) thus showing the potential of RS to get insight into the disease state of COPD. Principal Component Analysis (PCA) and Principal Component-based Linear Discriminant Analysis (PC-LDA) revealed that the healthy group can be stratified from the COPD group with an 80 % accuracy, while the asymptomatic smokers’ group can be distinguished from the COPD group with 70 % accuracy. Multivariate Curve Resolution (MCR) analysis revealed significantly higher lipid component abundance in NR and SN groups, compared to COPD. Further investigation is warranted with well-characterized larger sample size to reduce the spectral misclassification. The results of the RS investigation have the potential to be useful in the early identification of COPD.</div></div>","PeriodicalId":23656,"journal":{"name":"Vibrational Spectroscopy","volume":"138 ","pages":"Article 103798"},"PeriodicalIF":2.7,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143704623","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":"A novel perspective of ATR-FTIR spectroscopy combined with multiple machine learning methods for postmortem interval (PMI) human skin","authors":"Mingyan Deng ,&nbsp;Xinggong Liang ,&nbsp;Wanqing Zhang ,&nbsp;Shiyang Xie ,&nbsp;Shuo Wu ,&nbsp;Gengwang Hu ,&nbsp;Jianliang Luo ,&nbsp;Hao Wu ,&nbsp;Zhengyang Zhu ,&nbsp;Run Chen ,&nbsp;Qinru Sun ,&nbsp;Gongji Wang ,&nbsp;Zhenyuan Wang","doi":"10.1016/j.vibspec.2025.103800","DOIUrl":"10.1016/j.vibspec.2025.103800","url":null,"abstract":"<div><div>Due to the lack of simple, accurate, and reliable methods, the determination of PMI remains one of the most challenging tasks in forensic pathology, particularly during advanced stages of decomposition. Although numerous methods have been developed for PMI estimation, most are based on animal studies, and the extrapolation of these results to humans remains limited and questionable, providing limited practical utility. To address this gap, we collected a substantial number of human samples and focused on skin tissue, which shows significant potential but has been less extensively studied. ATR-FTIR spectroscopy combined with multiple machine learning algorithms was employed to monitor the spectral changes of skin at different PMI groups. Various algorithms (PLS-R, CLR, PCR, MLR, SVR, XGB-R, and ANN) were utilized to predict PMI. The results demonstrated that the chemical changes in lipids and proteins within postmortem skin tissue exhibited a strong time-dependent pattern. The intensity of lipid absorption peaks in fresh skin tissue was significantly higher than that in decomposed tissue, whereas amide I and II bands demonstrated the opposite trend, initially increasing and subsequently decreasing, which played a crucial role in distinguishing different time points and estimating PMI. The SVR model yielded highly satisfactory results, with the actual PMI showing close alignment with the predicted PMI. The R²CV reached 0.92, while the R²P achieved 0.96, with the RMSE as low as 2.0 days. The RMSEP/RMSECV value of 0.77 indicates the model's strong stability. These findings demonstrate that ATR-FTIR spectroscopy combined with machine learning holds significant potential and practical applicability for PMI estimation in actual forensic cases. This approach not only addresses the research gap in PMI estimation based on human skin samples but also establishes a new research direction in this field.</div></div>","PeriodicalId":23656,"journal":{"name":"Vibrational Spectroscopy","volume":"138 ","pages":"Article 103800"},"PeriodicalIF":2.7,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724630","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":"Exploring correlation in infrared spectroscopy","authors":"Thomas G. Mayerhöfer ,&nbsp;Susanne Pahlow ,&nbsp;Uwe Hübner ,&nbsp;Jürgen Popp","doi":"10.1016/j.vibspec.2025.103799","DOIUrl":"10.1016/j.vibspec.2025.103799","url":null,"abstract":"<div><div>Using theoretical and experimental transmission, transflection, and attenuated total reflection (ATR) spectra, we investigated how well corresponding absorbance spectra correlate with true absorbance, defined as the absorption index function multiplied by the wavenumber, using poly(methyl methacrylate) layers on CaF₂, Si, and gold substrates. To improve correlation, the substrate spectrum is often subtracted from the sample spectrum. A typical example is layers on CaF₂, where this approach is sufficient to establish a strong linear correlation. However, in many cases, the substrate spectrum is not a suitable reference for removing unwanted physical contributions, such as substrate-related effects. One such example is layers on Si substrates, where high reflectance causes the spectrum to be dominated by interference fringes. Instead of using the spectrum of an uncoated substrate, one must use the spectrum of a substrate with a non-absorbing layer that has the same refractive index in the transparency region between the MIR and visible spectral regions. For ATR spectra, a simple multiplicative correction based on the wavelength dependence of the penetration depth significantly increases the Pearson coefficient, though not to levels high enough for spectral recognition. To achieve higher accuracy, the Poor Man’s ATR Correction can be employed. For transflection spectra, all relatively simple methods generally fail, and only methods that ultimately determine the optical constant function show promise for success.</div></div>","PeriodicalId":23656,"journal":{"name":"Vibrational Spectroscopy","volume":"138 ","pages":"Article 103799"},"PeriodicalIF":2.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687699","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":"Merging Partial Least Squares & Raman spectroscopy to quantify oxidative stability in biodiesel","authors":"Maycom Cezar Valeriano ,&nbsp;Antonio Morais Neto ,&nbsp;Natalia Lima dos Santos ,&nbsp;Antonio Carlos Ferreira Batista ,&nbsp;Mónica Benicia Mamián-López","doi":"10.1016/j.vibspec.2025.103797","DOIUrl":"10.1016/j.vibspec.2025.103797","url":null,"abstract":"<div><div>As biodiesel is becoming more important as an alternative and cleaner biofuel in the energy transition, methodologies for monitoring its quality are necessary to guarantee the integrity of engines. One of the most relevant parameters in the quality control routine is oxidative stability, a characteristic related to the effect of oxygen in biodiesel at room temperature during storage. Quantifying the degree of oxidation in biodiesel is essential as undesirable products, such as sediments, polymers, or short-chain fatty acids, can be formed, significantly modifying its biofuel properties. In this work, for the first time, a rapid and non-destructive methodology based on Raman spectroscopy assisted by Partial Least Squares (PLS) regression was developed to quantify the oxidative stability of soy biodiesel by calibrating its Raman spectra against the induction time, monitored through the reference method. This combined strategy allows a fast and environmentally friendly methodology to quantify the induction time. With it, Root Mean Squared Error values for calibration and prediction of 0.2759 and 0.3260 h, respectively, were reached. These values were significantly lower than those reported by other spectroscopic methodologies, showing that merging the biodiesel's highly informative Raman features with the potentiality of chemometric modeling is very promising for rapid routine analyses that can be easily adapted outside the laboratory. Besides, this provides a substantial advancement in biodiesel quality control, considering that its use as a biofuel continuously grows worldwide.</div></div>","PeriodicalId":23656,"journal":{"name":"Vibrational Spectroscopy","volume":"138 ","pages":"Article 103797"},"PeriodicalIF":2.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687079","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":"Quantitative analysis of component contents in AS/PDM composite coagulant by infrared spectroscopy","authors":"Hao Wang,&nbsp;Yuhang Jiang,&nbsp;Xinjie Li,&nbsp;Yuejun Zhang","doi":"10.1016/j.vibspec.2025.103789","DOIUrl":"10.1016/j.vibspec.2025.103789","url":null,"abstract":"<div><div>In order to establish a quantitative analysis method for the components in the composite coagulant aluminum sulfate/poly dimethyl diallyl ammonium chloride (AS/PDM), this study first compared different sample preparation methods for infrared spectroscopy analysis. The electric hot plate drying method was selected due to its rapid sample preparation time and low moisture content. Based on the linear relationship between the mass ratio values of organic and inorganic components and the relative peak area ratio values of their characteristic infrared spectra, the mass ratio values were divided into four segments by order of magnitude. Samples were prepared for each segment, and their infrared spectra and corresponding relative peak area ratios were obtained. Different peak area calculation methods were compared, and four standard curves were constructed, with precision and recovery rates validated. Based on the measured mass ratio relationships between the components, the inorganic component Al₂O₃ content was determined using the EDTA back-titration method, completing the development of the quantitative analysis method for both components. Finally, verification using samples from four different mass ratio value segments demonstrated that when a linear lower bound for integration was used to calculate peak areas, the maximum relative error within the selected mass ratio value range was less than 5 %, which was significantly better than the results obtained using a curve as the lower bound for integration. Therefore, this method provides experimental evidence for the quantitative analysis of AS/PDM components and supports the establishment of quality standards for the product.</div></div>","PeriodicalId":23656,"journal":{"name":"Vibrational Spectroscopy","volume":"138 ","pages":"Article 103789"},"PeriodicalIF":2.7,"publicationDate":"2025-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143687698","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":"Investigating temperature-dependent spectral changes in human saliva using SERS on Ag and Au surfaces","authors":"Michaela Klenotová ,&nbsp;Pavel Matějka","doi":"10.1016/j.vibspec.2025.103788","DOIUrl":"10.1016/j.vibspec.2025.103788","url":null,"abstract":"<div><div>Surface-enhanced Raman Scattering (SERS) Spectroscopy, combined with multivariate data analysis such as Principal Component Analysis (PCA), effectively detects subtle changes in complex biological samples. In this study, we applied SERS to identify subtle molecular changes in human saliva deposited on large nanostructured Ag and Au substrates, focusing on the influence of temperature variations ranging from 10°C to 45°C. The selected temperature intervals – 10°C (cooling technology), 23°C (laboratory temperature), 37°C (physiological temperature), 42°C (fever), and 45°C (extreme temperatures) – reflect real-world conditions that biological and medical samples may encounter during collection, storage, transport, and analysis. We aimed to determine whether saliva samples remain stable at these temperatures over four days or if significant changes occur. Furthermore, we investigated the reversibility of spectral alterations during thermal jumps, where samples were heated to 45°C and then cooled back to 10°C. To ensure reliability, we utilized a computer-controlled mapping stage and a thermostatic sample holder, allowing precise temperature control and repeated recordings at identical locations on the substrate. Attention was given to intensity changes of marker bands, including band ratios, such as the ratio of 1175 cm⁻¹ to 1005 cm⁻¹ bands (<strong>protein hydration</strong> marker), the ratio of 856 cm⁻¹ to 831 cm⁻¹ bands (<strong>hydrophobicity</strong> marker of the environment surrounding <strong>tyrosine</strong>), and the ratio of 1360 cm⁻¹ to 1340 cm⁻¹ bands (<strong>hydrophobicity</strong> marker of the environment surrounding <strong>tryptophan</strong>) at different temperatures. The protein hydration marker exhibited a progressive decrease with increasing temperature, indicating water loss from the protein environment. In contrast, the hydrophobicity markers for tyrosine and tryptophan residues showed an increasing trend, suggesting enhanced hydrophobicity and a temperature-dependent reorganization of the protein structure on the SERS-active surfaces. In addition to these markers, we monitored changes related to amino acid residue bands for each temperature during the stability tests and thermal cycling. The spectral changes were associated with water loss and the reorganization of molecules near the nanostructured plasmonic surface, indicating saliva's sensitivity to temperature conditions. Our findings emphasize the importance of maintaining proper storage conditions for saliva films on large-area substrates to preserve sample integrity and prevent the misinterpretation of temperature-induced spectral changes. This study contributes to best practices for SERS analysis of thermally sensitive materials, particularly biofluids, especially in the context of medical diagnostics.</div></div>","PeriodicalId":23656,"journal":{"name":"Vibrational Spectroscopy","volume":"138 ","pages":"Article 103788"},"PeriodicalIF":2.7,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642784","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}