Spectrochimica Acta. Part A, Molecular And Biomolecular Spectroscopy[JOURNAL]
Sun
200 papers
Enhancement of up- and down-shifting luminescence for Alkali metal doping CsNaGdCl:Er double perovskite.
Liu H, Zhang J, Mi T … +4 more , Zhang J, Su L, Zhang A, Zhang Y
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42364480 · Publisher ↗
In this paper, a series of lead-free double perovskites CsNaGdCl: K/Er crystals are prepared with hydrothermal method. The up-conversion and down-shifting dual-mode luminescence properties of CsNaGdCl:K/Er perovskites ar...
In this paper, a series of lead-free double perovskites CsNaGdCl: K/Er crystals are prepared with hydrothermal method. The up-conversion and down-shifting dual-mode luminescence properties of CsNaGdCl:K/Er perovskites are investigated in detail. The up-conversion and down-shifting luminescence intensities of Er ions are enhanced due to induce K ion. Under 320 nm excitation, the self-trapped exciton emission of CsNaGdCl:K at 470 nm exhibits a 1.91-fold enhancement relative to pristine CsNaGdCl. In CsNaGdCl:4%K/5%Er, the total PL intensity of Er is enhanced by 1.36 times compared to CsNaGdCl:Er. Under 980 nm excitation, the green emission intensities of CsNaGdCl:K/Er DPs exhibits a 1.84-fold enhancement. The possible mechanism is discussed through luminescence spectra and lifetime decay curves. Meanwhile, the optical temperature sensing properties of CsNaGdCl:K/Er perovskites also are investigated based on the luminescence intensity ratio (LIR) technique. Under 980 nm excitation, the maximum relative sensitivity based on the LIR of one thermally coupled energy level pair (Er: H/S) reaches 3.242% K at 163 K. The results provide a new route to increase the luminescence intensity of CsNaGdCl:Er DPs.
Mechanistic study of α-glucosidase and α-amylase inhibition by taxifolin.
Ma S, Tang Y, Li T … +3 more , Zhu Z, Liu X, Xuan H
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42361652 · Publisher ↗
This study systematically investigated the inhibitory effects of the natural flavonoid taxifolin on the diabetes-related key hydrolytic enzymes α-glucosidase and α-amylase, as well as the underlying molecular mechanisms....
This study systematically investigated the inhibitory effects of the natural flavonoid taxifolin on the diabetes-related key hydrolytic enzymes α-glucosidase and α-amylase, as well as the underlying molecular mechanisms. The results demonstrated that taxifolin exhibited significant concentration-dependent inhibitory activity against both enzymes, acting as a competitive inhibitor of α-glucosidase and a mixed-type inhibitor of α-amylase. Fluorescence quenching analyses indicated that taxifolin primarily interacted with both enzymes through a static quenching mechanism, forming stable enzyme-ligand complexes. Further multispectroscopic analyses revealed that taxifolin markedly induced alterations in the secondary structure, conformation, and aggregation state of the enzymes, thereby impairing their catalytic activities. Molecular docking simulations showed that taxifolin could be accommodated within the active pockets of the enzymes and bind stably to key amino acid residues through multiple noncovalent interactions, including hydrogen bonding, π-π stacking, and hydrophobic interactions. In vitro simulated digestion experiments demonstrated that taxifolin significantly delayed starch hydrolysis and reduced glucose release. Moreover, in vivo zebrafish experiments confirmed that taxifolin markedly lowered postprandial glucose levels within 2 h. In summary, taxifolin binds the two enzymes and partially reduces postprandial glucose. Its mild hypoglycemic effect precludes its use as an antidiabetic drug, yet it shows promise as a functional food component with theoretical backing.
Simplification strategy for transitioning hyperspectral to multispectral instruments for quality evaluation of traditional Chinese medicine: a case study of wild and cultivated Ophiocordyceps sinensis.
Chen X, Cui X, Xie S … +7 more , Li J, Du H, Zhao L, Lan J, Fang J, Zhu Y, Liu S
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42361651 · Publisher ↗
Hyperspectral identification has been extensively investigated for evaluating the quality of Chinese herbal medicines; however, its practical application is hindered by prohibitive costs. The cost of hyperspectral instru...
Hyperspectral identification has been extensively investigated for evaluating the quality of Chinese herbal medicines; however, its practical application is hindered by prohibitive costs. The cost of hyperspectral instrument is primarily driven by the spectral coverage range and spectral resolution. Reducing the spectral coverage range can decrease the number of detector modules required, while lowering the spectral resolution can reduce the cost of dispersive components. The guiding principle of instrument simplification is to ensure that evaluation accuracy does not degrade significantly. This study proposes a two-step spectral simplification strategy that, while guaranteeing evaluation accuracy, maximally compresses both spectral range and resolution, transforming a hyperspectral spectrometer into a multispectral instrument. Using the identification of wild and cultivated Ophiocordyceps sinensis as a case study, through a data-simulation study utilizing hyperspectral band reconstruction, an eight-band multispectral design multispectral scheme with a 30 nm bandwidth was developed, resulting in the reduction of the system from three detector modules to one. This was achieved with a minimal trade-off in accuracy, dropping from 98.73% using the full spectrum to 97.51% with the multispectral scheme. This simplification strategy reduces the instrument cost to one-tenth of the original, providing a reference for the application of spectroscopy in the Chinese herbal medicine and food sectors.
Machine learning-enabled discrimination of tetracycline antibiotics by synergistic inner filter effect and antenna effect in Eu-functionalized silver nanoclusters.
Xiong Q, Zhao T, Liu Y … +6 more , Sui X, Xu Y, Wang C, Liu F, Xia C, Li N
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42361650 · Publisher ↗
Accurate discrimination of structurally similar antibiotics remains a major challenge due to the limited resolving capability of conventional sensing signals. Tetracycline antibiotics, which often coexist in complex matr...
Accurate discrimination of structurally similar antibiotics remains a major challenge due to the limited resolving capability of conventional sensing signals. Tetracycline antibiotics, which often coexist in complex matrices, typically generate highly overlapping responses, hindering reliable identification. Herein, a dual-emission fluorescence sensing platform based on Eu-functionalized silver nanoclusters (AgNCs@Eu) was developed to generate analyte-dependent signal patterns. Upon interaction with tetracyclines, the green emission of AgNCs is selectively attenuated through the inner filter effect, while the coordination between tetracyclines and Eu activates a characteristic red emission by the antenna effect. The synergistic modulation of these two signals produces partially overlapping but distinguishable fluorescence fingerprints for different tetracycline species. To resolve these subtle differences, machine learning algorithms were employed to decode the dual-channel fluorescence responses. The optimized model enables accurate classification of tetracycline, oxytetracycline, doxycycline, and chlortetracycline, with an accuracy up to 0.99. The platform further demonstrates robust performance in pharmaceutical, milk, and environmental water samples, maintaining reliable discrimination despite matrix interference. This work establishes a strategy that couples mechanism-defined dual-emission sensing with data-driven analysis, providing a practical route for the identification of structurally similar analytes in complex systems.
Experimental and theoretical study on the N(XΣ) vibrational temperatures estimation in nitrogen glow discharges.
Levaton J, Severo JHF, Novaes DO … +1 more , Amorim J
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42361649 · Publisher ↗
In the present work, we develop an experimental route for determining the N(XΣ) vibrational temperature in low-pressure flowing nitrogen glow discharges using only the Optical Emission Spectroscopy (OES) technique. The e...
In the present work, we develop an experimental route for determining the N(XΣ) vibrational temperature in low-pressure flowing nitrogen glow discharges using only the Optical Emission Spectroscopy (OES) technique. The emissions of the nitrogen Second Positive System (SPS) transitions, originated from the N(CΠ, 0 ≤ v' ≤ 4) states, are used to indirectly determine the N(XΣ, 0 ≤ v ≤ 4) distribution. For the first time, we explicitly derive the relation between the different electronic states populations solving the rate balance equations, using the definition of 'vertical' excitation from the N(CΠ, v') excitation cross-sections. Subsequently, the N(XΣ) vibrational distribution is fitted by either Boltzmann and Treanor functions furnishing two different experimental estimations for the vibrational temperature. The vibrational temperatures are estimated in two different discharge set-ups, for experimental conditions of discharge current from 15 to 75 mA, gas pressure from 160 to 1000 Pa, and gas flow rate from 0.2 to 1.0 Sl m varying independently. A well-established state-to-state kinetic numerical model we constructed to the study of the nitrogen discharges positive columns is modified to calculate the N(XΣ) vibrational temperature for our experimental conditions. The experimentally determined vibrational temperatures are quite well validated by our calculations for an extensive range of electron density (10-10 cm), reduced electric field (37-115 Td), and gas residence time (0.3-16 ms) discharges conditions. The work provides an original detailed analysis of experimental and theoretical routes to the N(XΣ) vibrational temperature determination in low-pressure nitrogen DC discharges.
Effects of bio-based solvents on bacterioruberin stability and spectroscopic properties.
Karpourazar N, Abady KK, Krishnamoorthi A … +1 more , Rentzepis PM
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42361648 · Publisher ↗
Bacterioruberin is a rare C50 xanthophyll carotenoid with exceptional antioxidant activity and scalable microbial bioproduction, making it a promising candidate for food, pharmaceutical, and biotechnological applications...
Bacterioruberin is a rare C50 xanthophyll carotenoid with exceptional antioxidant activity and scalable microbial bioproduction, making it a promising candidate for food, pharmaceutical, and biotechnological applications. However, the effect of solvents on its photophysical properties and stability remains poorly understood, limiting insight into its function in natural systems and its development for engineered applications. This study investigates the optical properties and stability of bacterioruberin extracted from Halobacterium salinarum across a series of bio-based solvents. Steady-state absorption, fluorescence, and resonance Raman spectroscopy reveal that solvent refractive index and hydrogen-bonding capacity govern spectral shifts and aggregation. Additionally, the molar extinction coefficient exhibits strong solvent dependence. Fluorescence emission and excitation spectra show deviations from Kasha's rule. Stability studies demonstrated that protic polar solvents provide the highest thermal and photostability, whereas dipolar aprotic and nonpolar solvents promote faster degradation, particularly under illumination. Moreover, micellar encapsulation and removal of co-extracted proteins further improve the stability of bacterioruberin. Collectively, these results advance our understanding of bacterioruberin photophysics and stability and establish a framework for the rational design of solvent environments in bacterioruberin-based technologies.
Integrated multispectroscopic and DFT analysis of molecular heterogeneity in Garabagh asphaltenes (Azerbaijan).
Yolchuyeva UJ, Abbasov VM, Abbasov OR … +8 more , Mammadov AM, Jafarova RA, Rahimov RA, Hajiyeva GA, Demiralp M, Çakmak NK, Maldonado EAL, Bouzid G
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42349151 · Publisher ↗
This study presents the first systematic analysis of the molecular architecture of asphaltenes isolated from Garabagh petroleum (Azerbaijan) by integrating multi-spectroscopic experimental methods with quantum-chemical m...
This study presents the first systematic analysis of the molecular architecture of asphaltenes isolated from Garabagh petroleum (Azerbaijan) by integrating multi-spectroscopic experimental methods with quantum-chemical modeling. Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) results reveal a heteroatom-rich (O + N + S = 22.2%), highly functionalized (CO, SO, NH), moderately aromatic (f = 0.478), and highly substituted (Σ = 0.54) structural framework. High-resolution mass spectrometry (HRMS) indicates a broad molecular weight distribution within the 145-800 Da range and confirms the presence of 4-6 fused aromatic-naphthenic fragments. X-ray diffraction (XRD) confirms an amorphous structure with coexisting aliphatic/aromatic domains and no crystalline order. Shows strong 300-600 nm absorbance, indicating pronounced π-π interactions. Thermogravimetric and differential thermogravimetric (TG/DTG) analyses show thermal stability up to 296 °C, decomposition in the 463-500 °C range, and 39.49% coke residue, which may be related to the presence of condensed aromatic nuclei. Density functional theory (DFT) optimized structural archetypes yield fragment-dependent HOMO-LUMO gaps (1.689-3.227 eV) and intramolecular H···O distances (1.647-1.693 Å). Hard fractions (η ≈ 1.614 eV) govern intrinsic chemical stability, while soft electrophilic isomers (σ ≈ 0.592 eV) exhibit enhanced reactive propensities. Collectively, the cross-validated results define an archipelago-dominant architecture, offering a unified molecular-level framework for interpreting the intrinsic electronic properties and molecular heterogeneity of asphaltenes.
Corrigendum to "Europium (III)-salicylate embedded carboxymethyl cellulose thin film immunosensor for ultrasensitive detection of breast cancer biomarker CA15-3: comprehensive experimental and computational insights" [Spectrochimica Acta Part A: Molecul. Biomol. Spectr. 359 (2026) 127942].
Mohammed KG, Mahdy EM, Radwan EM … +5 more , Abdellateif MS, Abdelgawad ME, Algethami FK, Attia MS, Abou-Omar MN
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42348978 · Publisher ↗
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Food additive dye indigo carmine induces amyloid fibrillation in beta-lactoglobulin at acidic pH: Spectroscopic and computational study.
Al-Shabib NA, Khan JM, Malik A … +4 more , AlAmri A, Rehman MT, AlAjmi MF, Husain FM
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42348977 · Publisher ↗
Synthetic food dyes are widely used, yet their interactions with dietary proteins remain poorly understood. Emerging evidence shows that some dyes promote protein aggregation, raising potential health concerns. Here, we...
Synthetic food dyes are widely used, yet their interactions with dietary proteins remain poorly understood. Emerging evidence shows that some dyes promote protein aggregation, raising potential health concerns. Here, we investigated whether indigo carmine (IC) can induce amyloid-like fibrillation of bovine β-lactoglobulin (BLG) under acidic conditions. Using spectroscopic methods, electrophoresis, and computational analyses, we explored the structural and mechanistic basis of IC-induced aggregation. Spectroscopy data revealed rapid BLG aggregation in the presence of 0.1-2.0 mM IC with no lag phase, consistent with isoseismic polymerization. Aggregation depended on both BLG and IC concentrations. SDS-PAGE showed the disappearance of protein bands at ≥0.1 mM IC, indicating extensive aggregation. Far-UV CD confirmed a shift from native β-sheet structure to cross-β architecture characteristic of amyloid fibrils. Environmental factors modulated fibrillation: NaCl and (NH₂)₂SO₄ enhanced solubilization of aggregates, with (NH₂)₂SO₄ having a stronger effect. PEG 4000 (1-20%) effectively disassembled fibrils and restored secondary structure. Docking and simulations suggested that electrostatic interactions between negatively charged IC and positively charged BLG residues promote charge neutralization, driving aggregation. These results revealed a unrecognized mechanism by which IC alters protein structure, offering insights relevant to food safety and regulation.
A portable smartphone-assisted fluorescent probe for the visualization and quantitative detection of ferric ions in aqueous solutions.
Zhang Y, Wang J, Zhang Y … +5 more , Wang S, Peng S, Jin Q, Wei E, Chen D
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42348976 · Publisher ↗
Accurate monitoring of ferric ions (Fe) in aquatic environments is essential, as elevated concentrations pose serious risks to human health and ecosystems. Herein, a fluorescent sensor based on blue-emissive carbon dots...
Accurate monitoring of ferric ions (Fe) in aquatic environments is essential, as elevated concentrations pose serious risks to human health and ecosystems. Herein, a fluorescent sensor based on blue-emissive carbon dots (B-CDs) has been developed for the detection of Fe in aqueous solutions. The B-CDs are prepared through a one-step solvothermal method using 5-aminoisophthalic acid and phloroglucinol as precursors and exhibit intense blue fluorescence. Upon the addition of Fe, the fluorescence of the B-CDs is significantly quenched due to the combined effects of the inner filter effect (IFE) and static quenching mechanism, enabling Fe detection with a limit of detection (LOD) of 92 nM over a linear range of 0.092-70 μM. In addition, a smartphone-integrated sensing system is constructed by immobilizing the B-CDs onto filter paper, facilitating on-site visual quantification of Fe with a LOD of 176 nM. Furthermore, the sensor exhibits recovery rates ranging from 97.5% to 103.8%, with relative standard deviations (RSDs) below 3.42%. These findings confirm the reliability and high accuracy of the proposed paper-based sensing platform for Fe detection in real samples. These results demonstrate that this portable and cost-effective sensing system offers an accurate and practical approach for Fe monitoring, with promising applications in health protection and environmental surveillance.
GSRCA: a grad-CAM-based method for spectral region and contribution quantification in interpretability analysis.
Zhai Y, Wu S, Sheng Y … +4 more , Fu M, Shen Y, Zhou Z, Yang Z
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42348975 · Publisher ↗
To address the fragmented point-wise gradients and limited physical interpretability of standard Grad-CAM in spectral analysis, this study proposes GSRCA (Grad-CAM-based Spectral Region and Contribution Analysis). Its co...
To address the fragmented point-wise gradients and limited physical interpretability of standard Grad-CAM in spectral analysis, this study proposes GSRCA (Grad-CAM-based Spectral Region and Contribution Analysis). Its core innovation lies in an adaptive region segmentation strategy that aggregates fragmented gradient points into continuous intervals corresponding to molecular vibrational modes. Based on a CNN framework, GSRCA first computes class-specific gradients via Grad-CAM, then employs a weight-distribution-based adaptive region segmentation strategy to aggregate discrete gradient responses into physically meaningful continuous spectral regions. Finally, the relative contribution of each region to the classification result is quantified through gradient integration and expressed as a percentage.On a Raman spectroscopy dataset containing six categories of illicit drugs, the key regions identified by GSRCA are generally consistent with characteristic vibrational bands reported in the literature, and region deletion/insertion tests further validate the effectiveness of the proposed contribution quantification scheme. Compared with conventional Grad-CAM, LIME, and SHAP-based methods such as GRASS, GSRCA shows better performance in regional integrity, physical interpretability, and computational efficiency. Experiments also show that the method requires no architecture-specific parameter tuning and can be transferred to dilated CNNs, Transformers, and remote sensing hyperspectral data, demonstrating model compatibility and generalization capability. GSRCA provides a physically interpretable and versatile explanation method for spectral classification models.
High-temperature reversible emission in a simple Schiff base: activated quenching, exciton-phonon renormalization, and tautomer-driven spectral evolution.
Fadaos M, Barhum H, Simanovsky I … +3 more , Ginzburg P, Matar M, Attrash M
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42348974 · Publisher ↗
Thermally robust solid-state emission remains rare among simple organic chromophores because elevated temperature usually enhances nonradiative decay, structural relaxation, and irreversible degradation. Here we investig...
Thermally robust solid-state emission remains rare among simple organic chromophores because elevated temperature usually enhances nonradiative decay, structural relaxation, and irreversible degradation. Here we investigate the thermal photophysics of the Schiff base para-phenylenediamine salicylaldehyde (SA-p-PD) bringing a unified kinetic and thermodynamic understanding. The material preserves measurable photoluminescence up to 200 °C and shows near-complete recovery on cooling, establishing reversible high-temperature luminescence. Across 300-473 K, the emission maximum shifts from approximately 580 to 600 nm, corresponding to a redshift coefficient of about 0.12 nm K. The intensity decay follows a Mott-Seitz description with an activation barrier near 0.22 eV, while lifetime shortening yields a comparable nonradiative barrier in the 0.18 eV range. A Bose-Einstein analysis links the continuous redshift to exciton-phonon coupling with an effective phonon energy of about 38 meV. Density-functional modeling and temperature-dependent spectral evolution both indicate that the high-temperature shoulder near 620 nm is associated with keto-like tautomeric emission. A thermodynamic population analysis further shows that a simple ground-state Boltzmann redistribution cannot, by itself, explain the strength of that shoulder: for a 0.20 eV enol-to-keto free-energy offset, the predicted keto population at 473 K remains below 1%. The data are therefore more consistent with a mixed mechanism consisting of a phonon-driven redshift of an enol-like emissive state together with a thermally activated keto-like emissive branch. This framing turns SA-p-PD from a single thermochromic emitter into a compact model system for studying coupled quenching, lattice-assisted spectral renormalization, and excited-state tautomerism. Contrasting the temperature evolution of peak energy, integrated intensity, lifetime, and low-energy shoulder growth further shows that gap renormalization precedes the dominance of nonradiative loss and that a simple ground-state Boltzmann picture is insufficient to explain the hot-state 620 nm feature.
DFT insights into dopamine adsorption on pristine and Ag-doped carbon nanotubes: implications for SERS sensing applications.
Al-Otaibi JS, Mary YS, Kumar YB … +3 more , Resmi KS, Jhaa G, Gamberini MC
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42348973 · Publisher ↗
In this work, DFT was used to investigate the adsorption behaviour of dopamine on pristine and Ag-doped carbon nanotubes. Two adsorption orientations, involving hydroxyl and amine groups of dopamine, were examined to cla...
In this work, DFT was used to investigate the adsorption behaviour of dopamine on pristine and Ag-doped carbon nanotubes. Two adsorption orientations, involving hydroxyl and amine groups of dopamine, were examined to clarify role of functional-group direction in molecule-surface interactions. The results show that Ag doping strongly enhances dopamine adsorption by increasing charge transfer, surface polarization, and orbital coupling. Among the studied systems, CNTAgNH exhibited strongest adsorption energy, highest dipole moment, and most favourable thermodynamic stability, indicating strong Ag-mediated interaction through amine group. FMOs, MEP, DOS, NCI, and RDG analyses further confirmed that Ag incorporation narrows the electronic gap and introduces active interaction sites. Vibrational analysis revealed significant shifts in OH, NH, phenyl, and CH modes after adsorption, supporting enhanced chemical interaction and possible SERS signal amplification. Overall, Ag-doped CNTs, particularly the CNTAgNH configuration, appear to be promising nanosubstrates for dopamine detection, although very strong adsorption may reduce sensor recyclability.
A flexible ag/PDMS hemispherical array SERS for rapid "touch-and-wipe" sampling and quantitative screening of multi-class contaminants.
Zhang H, Yuan J, Fang G … +4 more , Zhang B, Li W, Zhang J, Hasi W
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42348972 · Publisher ↗
This study developed a highly sensitive, reproducible, and flexible SERS sensing platform based on an ordered silver nanoparticle (Ag NPs)-coated polydimethylsiloxane (PDMS) hemispherical array. A dense and uniform Ag NP...
This study developed a highly sensitive, reproducible, and flexible SERS sensing platform based on an ordered silver nanoparticle (Ag NPs)-coated polydimethylsiloxane (PDMS) hemispherical array. A dense and uniform Ag NPs film was fabricated via a Marangoni effect-driven interfacial self-assembly strategy and subsequently transferred onto a micro-replicated PDMS hemispherical array to create a hierarchical 3D plasmonic architecture. This design significantly increases the density of "hotspots" and the effective surface area compared to flat substrates, achieving a high analytical enhancement factor (AEF) of 2.89 × 10. The flexible nature of the Ag/PDMS substrate allows for efficient, direct "touch-and-wipe" sampling from irregular surfaces, such as fish skin, apple peels, and chili peppers. Furthermore, by coupling the substrate with a portable 1064 nm Raman spectrometer, fluorescence background from real-world samples was effectively suppressed, enabling reliable on-site quantification. The platform demonstrated excellent reproducibility with a relative standard deviation (RSD) of 8.52% and achieved low detection limits for crystal violet (CV), thiram, and rhodamine B (RhB) in the range of 10 M. Practical applications revealed robust linear correlations for contaminant detection on diverse food surfaces. These results highlight the immense potential of this sensor for rapid, non-destructive, and quantitative food safety monitoring in field environments.
Rapid colorimetric detection of kanamycin in water using dual-mechanism enhanced AuNPs aggregation with smartphone readout.
Yang Y, Zhao Y, Wang Y … +7 more , Yin Z, Feng M, Fan Y, Linhu T, Li J, Deng D, Xu S
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42341463 · Publisher ↗
Kanamycin (Kana) residues in water pose significant threats to ecosystems and human health, highlighting the need for rapid and simple on-site monitoring methods. Conventional salt-induced aggregation of gold nanoparticl...
Kanamycin (Kana) residues in water pose significant threats to ecosystems and human health, highlighting the need for rapid and simple on-site monitoring methods. Conventional salt-induced aggregation of gold nanoparticles (AuNPs) for colorimetric detection often suffers from limited sensitivity and poor color contrast. Herein, we report a dual-mechanism enhanced colorimetric biosensor that combines charge neutralization by positively charged Kana with charge shielding by NaCl to amplify AuNPs aggregation. This synergistic effect triggers a distinct color change from wine-red to dark blue within 3 min, enabling rapid visual and quantitative detection of Kana. The aggregation behavior of AuNPs was characterized by UV-Vis spectroscopy, transmission electron microscopy, dynamic light scattering, and Zeta potential measurements. Under optimized conditions, the sensor exhibited a linear range of 5-250 nM with a limit of detection (LOD) of 4.4 nM based on UV-Vis analysis. Smartphone-based RGB analysis achieved instrument-free quantification in the range of 0-250 nM, with an LOD of 2.3 nM. The biosensor also demonstrated excellent selectivity toward Kana against common interfering substances and was successfully applied to spiked environmental water samples, yielding recoveries of 94.69%-105.90% with RSDs below 7.34%. This work provides a rapid, sensitive, and portable platform for on-site monitoring of antibiotic contamination.
Near infrared spectroscopy combined with interval selective ensemble learning for analysis of cement raw meal component contents.
Ma X, Cai Y, Huang B … +3 more , Zhang R, Wang X, Ju D
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42341462 · Publisher ↗
Detecting the component contents of raw meal is an important step in the quality control of the cement industry. Near infrared spectroscopy (NIRS) has demonstrated a significant application potential in the quality contr...
Detecting the component contents of raw meal is an important step in the quality control of the cement industry. Near infrared spectroscopy (NIRS) has demonstrated a significant application potential in the quality control of cement raw meal. This study proposes an interval selective ensemble learning (ISEL) method for quantitative analysis of CaO, SiO, AlO and FeO in cement raw meal using NIRS. Firstly, the spectral data are divided into several sub-intervals to train individual learners. Then the K-means algorithm is used to cluster and select dominant individual learners from trained individual learners. The stacking integration strategy is used to combine the outputs of the advantageous individual learners. The cross-validation outputs of dominant individual learners are combined to construct a meat-training set, which is used to train a multilayer perceptron (MLP) for nonlinear integration of dominant individual learners. ISEL is validated on two NIRS datasets obtained from different cement plants and measured with different types of spectrometers. Experimental results show that the proposed ISEL outperforms widely used chemometric methods as well as ensemble and selective ensemble approaches. For dataset A, R are 0.9721, 0.9476, 0.9383 and 0.9255, with RMSEP of 0.181%, 0.2015%, 0.0698% and 0.056%. For dataset B, the R and RMSEP are 0.9247, 0.8544, 0.8474, 0.8363 and 0.1868%, 0.2238%, 0.0781%, 0.0328%, respectively. This study demonstrates that NIRS couples with the ISEL is a novel and reliable approach for the quantitative analysis of cement raw meal.
Raman evidence for a solvation-heterogeneity-mediated precipitation pathway of sodium sulfate in water-DMSO mixtures.
Jiang H, Chen L, Feng Z … +4 more , Xu X, Sun J, Sun C, Liu M
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42335707 · Publisher ↗
Salt precipitation in water-organic solvent mixtures is generally interpreted in terms of enhanced ion association driven by reduced water activity. Here, Raman spectroscopy and molecular dynamics (MD) simulations reveal...
Salt precipitation in water-organic solvent mixtures is generally interpreted in terms of enhanced ion association driven by reduced water activity. Here, Raman spectroscopy and molecular dynamics (MD) simulations reveal a different precipitation mechanism for NaSO in water-DMSO mixtures. Increasing DMSO content causes a systematic redshift of the sulfate Raman band and the emergence of a low-wavenumber sulfate population near saturation. Simulations show that DMSO is largely excluded from the first solvation shell of SO, preserving a locally water-rich hydration structure even as the bulk water network becomes strongly disrupted. Consistent with this picture, neither contact ion pairs nor large ionic aggregates become dominant prior to precipitation. Instead, the results support a solvation-heterogeneity-mediated pathway in which distinct hydrated sulfate environments persist up to the precipitation threshold. Crystallization is subsequently triggered by the collapse of hydration stability rather than by extensive ion aggregation. These findings provide molecular-level insight into ion-specific solvation effects in mixed-solvent crystallization.
Mechanism guided near-infrared determination of soluble solids content in whole European plum based on optical properties and Monte Carlo simulation.
Zhang H, Su Q, Li Q
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42335706 · Publisher ↗
Soluble solids content (SSC) is a key indicator of sweetness and quality in European plum, yet rapid and non-destructive detection methods remain limited. This study aimed to develop an optical property-guided near-infra...
Soluble solids content (SSC) is a key indicator of sweetness and quality in European plum, yet rapid and non-destructive detection methods remain limited. This study aimed to develop an optical property-guided near-infrared (NIR) detection method for SSC in whole European plum. An integrating sphere system combined with the inverse adding-doubling (IAD) algorithm was used to determine the absorption coefficient (μ), reduced scattering coefficient (μ'), and anisotropy factor (g) of plum peel and flesh. The relationships between optical properties and SSC were analyzed, and optical penetration depths were calculated. Voxel-based Monte Carlo simulations were further performed to investigate photon transport in plum tissues and to optimize the detection configuration. Results showed that SSC variation was mainly associated with the absorption coefficient of the flesh. Light in the range of 900-1350 nm could penetrate the peel and reach the flesh tissue. Diffuse reflectance was identified as an effective detection mode, and the integrating sphere enabled a balance between sampling depth and signal intensity. The informative spectral regions were further refined to 900-950 nm and 1010-1125 nm based on penetration depth and detector sampling characteristics. Based on the optimized detection scheme, NIR spectra were collected and separately preprocessed using SG and MSC before modeling. Prediction models were developed using PLSR, SVR, and LSSVM. The results of the validation experiments showed that the MSC-LSSVM model achieved the best performance (R = 0.887, RMSE = 0.024, and RPD = 2.946), indicating reliable predictive ability for SSC. This study provides a mechanistic and practical basis for non-destructive SSC detection in European plum and supports the development of rapid optical sensing methods.
Interpretable Raman phenotyping of human granulosa cells aligns with endocrine-defined ovarian status.
Xiong W, Zhao W, Wu Y … +2 more , Mao S, Li Y
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42335705 · Publisher ↗
Assessment of ovarian status in in vitro fertilization (IVF) is critically reliant on systemic endocrine and morphological markers, which often lack the temporal resolution and mechanistic specificity to predict individu...
Assessment of ovarian status in in vitro fertilization (IVF) is critically reliant on systemic endocrine and morphological markers, which often lack the temporal resolution and mechanistic specificity to predict individual oocyte competence, necessitating a proximal, label-free molecular phenotype. Here, we present a high-definition, label-free Raman microspectroscopy pipeline for the non-destructive phenotyping of human granulosa cells (GCs)-the essential somatic niche of the oocyte. By profiling 140 participants using a participant-anchored analytical framework and machine learning, we identified a robust biochemical axis that discriminates between good ovarian status (GOS) and poor ovarian status (POS) cohorts. GOS cells are characterized by significantly higher intensities in lipid (1444, 2856, and 2928 cm) and amide bands, reflecting enhanced steroidogenesis and membrane remodeling. Conversely, POS cells exhibit a relative prominence in nucleic-acid-linked features (915 and 1180 cm), suggesting altered biosynthetic balance or stress signatures. Our convolutional neural network models leveraged this molecular gradient to achieve a participant-level Receiver-Operating Characteristic (ROC) area of 0.882 on a blinded test cohort. These spectral markers showed concordance with established endocrine indices (AMH and FSH), anchoring the Raman phenotype to endocrine-defined ovarian status. This study therefore establishes interpretable granulosa-cell Raman phenotyping as a reproducible molecular readout aligned with endocrine stratification. Further validation against clinically meaningful reproductive outcomes and in external multicenter cohorts will be required to determine translational value beyond current endocrine assessment.
Unveiling the sensing mechanism of a Nile Red-naphthoquinone H₂S fluorescent probe: theoretical calculation and deep learning prediction.
Liu L, Xu KR, Xiao ZX … +4 more , Fu L, Peng YJ, Han D, Jia A
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42335704 · Publisher ↗
Hydrogen sulfide (H₂S) is a vital endogenous gasotransmitter implicated in numerous physiological and pathological processes; thus, its precise detection in biological and environmental systems is of great significance....
Hydrogen sulfide (H₂S) is a vital endogenous gasotransmitter implicated in numerous physiological and pathological processes; thus, its precise detection in biological and environmental systems is of great significance. This work is a theoretical computational study aiming to interpret the sensing mechanism of a previously reported Nile Red-naphthoquinone fluorescent probe NR-H₂S. A comprehensive investigation combining systematic theoretical calculations and deep learning prediction was carried out. Theoretical analyses including average local ionization energy (ALIE), density of states (DOS), charge decomposition analysis (CDA) and electron-hole distribution provide theoretical evidence that the fluorescence quenching of NR-H₂S originates from a photoinduced electron transfer (PET) process. Specifically, ALIE identified electrophilic reaction sites of the molecules. DOS and CDA results revealed that the highest occupied molecular orbital (HOMO) is dominated by the Nile Red moiety, while the lowest unoccupied molecular orbital (LUMO) is localized on the 2,3-dichloro-1,4-naphthoquinone unit, which facilitates efficient PET quenching. Furthermore, the FLSF (FLuorescence prediction with fluoroScaFfold-driven model) deep learning model was adopted to quantitatively predict key photophysical properties of NR-H₂S and its reaction product NR-OH. The predictions from FLSF are broadly consistent with the low photoluminescence quantum yield of NR-H₂S caused by PET quenching and the distinct fluorescence enhancement of NR-OH, which agrees well with experimental trends and quantum chemical results. This study not only offers a reliable reference for the rational design of H₂S-selective fluorescent probes, but also demonstrates the complementary value of quantum chemical calculations and artificial intelligence in accelerating the research and development of advanced optical functional materials.
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