Spectrochimica Acta. Part A, Molecular And Biomolecular Spectroscopy[JOURNAL]
Sun
200 papers
High-sensitivity optical thermometry in CaWO: Bi, Pr phosphors based on distinct thermal quenching behaviors.
Sun B, Meng Q, Sun W
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42288092 · Publisher ↗
Within the present investigation, varying-concentration Bi, Pr co-doped CaWO samples were prepared via the hydrothermal approach. The present comprehensive investigation was performed into their optical temperature sensi...
Within the present investigation, varying-concentration Bi, Pr co-doped CaWO samples were prepared via the hydrothermal approach. The present comprehensive investigation was performed into their optical temperature sensing characteristics. Experimental results indicate that, in the CaWO host, the emission characteristics of Bi shows a pronounced tendency toward thermal luminescence quenching, while the thermal luminescence quenching process of Pr emission is significantly slower in comparison with Bi. Therefore, the FIR of Pr and Bi rises markedly as the temperature elevates, a property that allows it to be employed for temperature characterization, and achieved a relatively higher sensitivity. The prepared phosphors can achieve temperature characterization through two sets of FIR: I/I and I/I, corresponding to Pr (D → H, P → F) and Bi (P → S). The acquired results can cross-verify one another, thus enabling the realization of self-calibration. In the case where the FIR of I/I is used for temperature characterization, exhibits the highest S of 4.36% K (in the CaWO co-doped with 5 mol% Bi and 0.5 mol% Pr phosphor at 298 K). When the FIR of I/I is used for temperature characterization, exhibits the highest S of 4.06% K (in the CaWO co-doped with 5 mol% Bi and 0.5 mol% Pr phosphor at 298 K). Furthermore, with an increase in temperature, the emission color of the phosphors gradually changes from the blue region to the orange-red region, this luminescent color change allows for the rough estimation of temperature. Findings from the present investigation demonstrate that CaWO: Bi, Pr phosphors possess considerable practical application value in the realm of luminescence thermometry.
Tunable photoluminescence and investigation on the Pr → Eu energy transfer mechanism based on NaGdF:Pr, Eu@void @SiO ball-in-tube structured nanofibers prepared by one-step fluorination method.
Xue R, He Z, Lv C … +2 more , Li D, Dong X
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42288091 · Publisher ↗
NaGdF:Pr, Eu@void @SiO ball-in-tube structured nanofibers (BITSN) with tunable luminescent colors are successfully obtained by combining single-axis electrostatic spinning and one-step fluorination in a single crucible....
NaGdF:Pr, Eu@void @SiO ball-in-tube structured nanofibers (BITSN) with tunable luminescent colors are successfully obtained by combining single-axis electrostatic spinning and one-step fluorination in a single crucible. The products exhibit a pure hexagonal crystalline structure. The average diameters of PVP/[NaNO + Gd(NO) + Pr(NO) + Eu(NO) + TEOS] pristine nanofibers and NaGdF:Pr, Eu@void@SiO BITSN are 476.52 ± 39.54 nm and 462.77 ± 30.37 nm, respectively. NaGdF:x%Pr@void@SiO (x = 0.2, 0.3, 0.5, 0.7, 1) BITSN and NaGdF:0.7%Pr, y%Eu@void@SiO (y = 0.5, 1, 2, 3, 5) BITSN have been effectively fabricated to study phenomenon of energy transfer and the adjustable alteration of light color. The luminescence spectra of the samples have demonstrated the occurrence of energy transfer from Pr ions to Eu ions. NaGdF:Pr, Eu@void@SiO BITSN show white light emission and multicolor luminescence. The introduction of Pr as a sensitizer alongside Eu establishes a multistep energy transfer channel of Gd → Pr → Eu. By simultaneously adjusting the excitation wavelength (273 nm, 393 nm or 444 nm) and the Pr/Eu doping ratio, the emission color can be tuned over a wide range. The materials have promising applications in displays, cancer treatment, medication delivery, lighting, optical visualization, MRI, and biomedical fields. This work proposes a new method for constructing ball-in-tube structured nanofiber, providing a new perspective for the preparation of other nanomaterials with unique structures.
Spectroscopic insights into the dual-mode sensing of uric acid by iron-doped carbon dots: peroxidase-like activity and the inner filter effect.
Sun Y, Cheng Y, Chen K … +2 more , Ge Y, Wu F
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42288090 · Publisher ↗
Enzymatic assays have been widely used for uric acid (UA) detection owing to their high specificity and favorable catalytic efficiency, playing an indispensable role in clinical diagnosis and point-of-care testing. Never...
Enzymatic assays have been widely used for uric acid (UA) detection owing to their high specificity and favorable catalytic efficiency, playing an indispensable role in clinical diagnosis and point-of-care testing. Nevertheless, the practical applications of natural enzymes in sensing and detection are severely limited by their high cost and poor structural stability. Herein, a potent peroxidase-mimetic nanoagent was developed from iron-doped carbon nanodots (Fe-CDs). This material enabled a dual-signal output (colorimetric/fluorometric) for UA analysis. Fe-CDs exhibited robust peroxidase-like activity and catalyzed the conversion of colorless 3,3',5,5'-tetramethylbenzidine (TMB) into a visible blue oxidized TMB (oxTMB) signal via a superoxide radical (O)-dominated pathway, while simultaneously suppressing the native fluorescence of Fe-CDs through the inner filter effect (IFE). Introduction of UA reduced the oxidized TMB, triggering a coordinated color-fading and fluorescence-recovery response. Exceptional sensitivity to urate is demonstrated by the dual-channel LODs, which stand at 0.177 μM (colorimetric) and 0.067 μM (fluorometric). The platform exhibited outstanding selectivity against both single interferents and a mixture of common reducing species, enabling reliable UA quantification in complex biological matrices. Practical performance was validated in fetal bovine serum and healthy human urine, with recoveries of 99.06-100.47% (RSD < 6.03%) and 95.2-106.8% (RSD < 4.37%), respectively. Our findings provide spectroscopic insights into the catalytic and fluorescence modulation mechanisms of Fe-CDs, highlighting their potential as a precise and cost-effective probe for clinical UA analysis.
Methanol detection under variable humidity conditions using an improved wavelength modulation spectroscopy method based on first harmonic signal analysis.
Wang R, Sun L, Xiong Y … +1 more , Yin P
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42288089 · Publisher ↗
Methanol is a hazardous volatile organic compound, and its reliable detection under varying ambient conditions remains challenging, particularly due to interference from water vapor. In this work, an improved wavelength...
Methanol is a hazardous volatile organic compound, and its reliable detection under varying ambient conditions remains challenging, particularly due to interference from water vapor. In this work, an improved wavelength modulation spectroscopy (WMS) method based on first-harmonic (1f) signal analysis is proposed for methanol measurement under variable humidity. By applying a logarithmic transformation to the transmitted intensity, a linear relationship between the 1f signal and methanol concentration is established without relying on the absorption line shape. Furthermore, a point-selection strategy is introduced to suppress water-vapor interference, by selecting a wavelength where the first-harmonic (1f) contribution of water vapor is nearly zero-corresponding to its absorption peak-thereby enabling direct concentration retrieval of methanol. The proposed method was validated via calibration experiments, exhibiting excellent linearity with a coefficient of determination R = 0.999. Allan deviation analysis yielded a minimum detectable concentration of 182 ppb at an optimal integration time of 8.2 s. Measurements under different humidity levels showed stable retrieved methanol concentrations, with a maximum relative error of 3.1%. A comparative study confirmed that the proposed 1f-based method significantly outperforms the conventional 2f-based approach in accuracy, detection limit, and robustness against humidity variations. These results demonstrate that the proposed method offers a reliable and effective solution for methanol detection in environments with fluctuating humidity.
A SERS-active molecularly imprinted polymer sensor for ultrasensitive detection of microcystin-LR in water and its application in water safety monitoring.
Ghaderi S, Hassanzadeh A, Hallaj R
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42284868 · Publisher ↗
This work presents a surface-enhanced Raman scattering (SERS)-based molecularly imprinted polymer (MIP) platform for ultrasensitive and selective determination of microcystin-LR (MC-LR) in water. The strategy combines mo...
This work presents a surface-enhanced Raman scattering (SERS)-based molecularly imprinted polymer (MIP) platform for ultrasensitive and selective determination of microcystin-LR (MC-LR) in water. The strategy combines molecular imprinting for selective recognition of MC-LR with SERS as a label-free analytical readout. MC-LR was used as the template, and a sol-gel copolymer based on 3-aminopropyltriethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) was employed for MIP fabrication. The plasmonic effect of silver nanowires (AgNWs) was integrated with the MIP by coating a uniform and thin sol-gel layer onto the AgNW surface (AgNW@MIP). After template removal, the AgNW@MIP/MC-LR system exhibited over 30-fold Raman signal enhancement. A good linear relationship was obtained between Raman intensity and MC-LR concentration, achieving a detection limit of 5.4 ngL over a range of 6.4 ngL to 500 μgL. The sensor was successfully applied to reservoir water samples, showing good agreement with ELISA.
Agricultural waste to green catalyst: Lupinus peel-supported cobalt-based catalyst for environmental remediation.
Eisa WH, Zeid AMA, Anis B … +1 more , Zayed MF
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42284867 · Publisher ↗
A different approach to using agricultural waste as a solid support for nanocatalysts was developed. The waste itself was used, without the need to convert it into carbon-based compounds or perform liquid extractions, as...
A different approach to using agricultural waste as a solid support for nanocatalysts was developed. The waste itself was used, without the need to convert it into carbon-based compounds or perform liquid extractions, as was previously the case. Our method combined the use of the waste's chemical structure to stabilize the nanoparticles with its physical form (film-like), which allowed for easy separation and reuse. Lupinus albus peel (LAP) was used as solid support for Co-based catalyst (denoted as Co@LAP) and evaluated as green catalyst for the degradation of organic pollutants. The prepared Co nanoparticles have an average crystallite size of 33 nm, as calculated using X-ray diffraction (XRD) and have a semi-spherical shape as shown by scanning electron microscopy (SEM). The catalytic activity of Co@LAP toward the degradation of 4-nitrophenol (4-NP) and methyl orange (MO) was evaluated. These results highlight the potential of agricultural waste as efficient, economical, and eco-friendly matrix for environmental remediation, providing a promising alternative to traditional heterogeneous catalysts.
Viscosity-activated near-infrared fluorescent probe for paw edema diagnosis and evaluation of herbal efficacy.
Yu Y, Xia C, Wu Y … +5 more , Zhang L, Zhang X, Wang Y, Long G, Wang W
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42284866 · Publisher ↗
Paw edema (PE), as a typical acute inflammatory model, is accompanied by significant alterations in cellular viscosity during its progression. Currently, the mainstream methods for evaluating the anti-inflammatory effica...
Paw edema (PE), as a typical acute inflammatory model, is accompanied by significant alterations in cellular viscosity during its progression. Currently, the mainstream methods for evaluating the anti-inflammatory efficacy of herbs have limitations such as operational complexity, invasiveness and non-real-time, making it urgent to develop a new method for efficacy assessment. Herein, a novel near-infrared (NIR) fluorescent probe named BXN with long absorption and emission wavelengths was developed for visualizing viscosity in inflammation and evaluating drug efficacy. BXN has a typical D-π-A molecular structure, formed by the conjugation of benz[c,d]indole and xanthene. The fluorescence of BXN is negligible in low-viscosity solvents. Under high viscosity conditions, the maximum absorption of BXN red-shifted to 750 nm, and the fluorescence intensity at 800 nm increased by 84-fold. Meanwhile, BXN towards viscosity exhibits excellent selectivity, sensitivity and good biocompatibility. Furthermore, BXN has enabled the visualization of cell viscosity under different drug stimulation, and can distinguish between normal cells and cancer cells. Based on the NIR emission of BXN, the abnormal increase of viscosity in paw edema mice is confirmed for the first time through fluorescence imaging. More importantly, after treatment with Bryophyllum pinnatum (BP), it is possible to dynamically and intuitively monitor the significant reduction in the viscosity of the foot, further achieving a non-invasive and real-time assessment of the anti-inflammatory effect of herbal BP. In conclusion, BXN not only provides a new tool for the diagnosis of inflammatory diseases, but also establishes a new method for evaluating herbal efficacy in real-time and non-invasive.
Machine learning UV-vis spectroscopy for total nitrogen and phosphorus measurement in wastewater with wavelength-wise insight.
Luo Y, Liu S, Xin H … +12 more , Zhang Z, Leng G, Zhang H, Wang S, Luo J, Xu W, Luo X, Wang Y, Xie Z, He L, Wang J, Pei L
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42284865 · Publisher ↗
High-quality total nitrogen (TN) and total phosphorus (TP) data are essential for wastewater management and aquatic ecosystem protection, yet routine determinations rely on labor- and reagent-intensive wet chemistry. Ult...
High-quality total nitrogen (TN) and total phosphorus (TP) data are essential for wastewater management and aquatic ecosystem protection, yet routine determinations rely on labor- and reagent-intensive wet chemistry. Ultraviolet-visible (UV-Vis) spectroscopy offers a rapid, low-consumable alternative, but TN/TP quantification in heterogeneous wastewater remains challenging because they are composite indices with weak, dispersed spectral features and strong matrix effects. Here we introduce a task-specific machine learning framework for TN/TP measurement via UV-Vis. TN is modeled with eXtreme Gradient Boosting (XGB) on pretreated spectra to capture nonlinearities with built-in regularization; TP, whose spectral cues are weaker and more dispersed, is addressed by a 1D-CNN-XGB hybrid pipeline, where the CNN distills shift-tolerant local motifs and reduces collinearity before nonlinear regression by XGB. The proposed method achieves R = 0.9691 (RPD = 5.94) for TN and R = 0.8738 (RPD = 3.43) for TP. Wavelength-resolved attributions with latent back-projection reveal distinct spectral drivers: TN is dominated by compact deep-UV motifs with a secondary UV band and minor near-UV features consistent with matrix/background variability, whereas TP follows a distributed, shape-based multi-band UV rule captured by the CNN. This framework outlines an effective and interpretable UV-Vis approach for TN/TP measurement in wastewater and may enable rapid, in-situ, low-consumable monitoring workflow towards field deployment.
Identification and content prediction of antibiotics in milk based on fluorescence hyperspectral technology.
Long Y, Bian Y, Song F … +5 more , Jin G, Li Z, Teng H, Xu W, Song C
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42284864 · Publisher ↗
Antibiotic residues in milk affect the quality and safety of dairy products, which are crucial to the health of consumers and the sustainable development of the dairy industry. This study utilizes fluorescence hyperspect...
Antibiotic residues in milk affect the quality and safety of dairy products, which are crucial to the health of consumers and the sustainable development of the dairy industry. This study utilizes fluorescence hyperspectral imaging (F-HSI) technology in combination with machine learning algorithms for the rapid, nondestructive detection of quinolone antibiotics (ciprofloxacin, ofloxacin) and chloramphenicol antibiotics in milk. The results demonstrated that the MSC-whole-band-SVM and MSC-RF-SVM combination classification models performed the best, with accuracies of 100% for the calibration set and 97.5610% for the prediction set. The original spectrum-SPA+2D-COS-PLSR algorithm model was the best quantitative model for ciprofloxacin residue samples, with an R2 P of 0.88167 and an RMSEP of 0.030637. The MSC-RF + 2D-COS algorithm model was the best quantitative model for ofloxacin residue samples, with an R2 P of 0.89832 and an RMSEP of 0.030531. The SNV-RF + 2D-COS algorithm model was the best quantitative model for chloramphenicol residue samples, with an R2 P of 0.8755 and an RMSEP of 0.036625. These results indicate that F-HSI combined with machine learning can effectively identify and predict the type and concentration of antibiotic residues in milk, and further evaluation under regulatory standards and practical conditions may enhance understanding of its applicability.
Fluorescence detection of 2,4-dinitrophenol and 2,4,6-trinitrophenol using the 2D benzimidazole-linked covalent organic frameworks.
Geng TM, Gui YL, Li XY … +2 more , Pan R, Xu H
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42284863 · Publisher ↗
Due to their electron-rich nature, benzimidazole-linked COFs should exhibit excellent fluorescence sensing properties for nitroaromatic compounds (NACs). However, there has been no report on the application of benzimidaz...
Due to their electron-rich nature, benzimidazole-linked COFs should exhibit excellent fluorescence sensing properties for nitroaromatic compounds (NACs). However, there has been no report on the application of benzimidazole-linked COFs for fluorescence sensing NACs. This study reports two 2D benzimidazole-linked COFs, which were prepared via Schiff base polymerization and cyclicization reaction of 3,3'-diaminobenzidine (DAB) or 1,2,4,5-benzenetetramine tetrahydrochloride (TAB) with ether-linked knot, TPT-3-CHO (TDAB and TTAB). TDAB and TTAB exhibit large specific areas of 2087 and 1912 m g, excellent crystallinity, and high thermal and chemical stability. The porous 2D benzimidazole-linked COFs can serve as fluorescent sensors for the selective and sensitive detection of 2,4-dinitrophenol (DNP) and 2,4,6-trinitrophenol (TNP), exhibiting high quenching constants (K) and low limits of detection (LODs). The K values and LODs of TDAB for DNP are 2.66 × 10 L moland 3.24 × 10 mol L, and these of TDAB for TNP are 2.55 × 10 L mol and 3.79 × 10 mol L. The K values and LODs of TTAB for TNP are 1.06 × 10 L moland 4.65 × 10 mol L. The fluorescence quenching arises from both photoinduced electron transfer mechanism and absorption competition quenching mechanism. This study authenticates that benzimidazole-linked COFs are promising candidates as fluorescent chemosensors, and opens new avenue for exploring their potential applications to detect NACs for pollution control and prevention.
A pyranopyrazole-rhodamine chemosensor for selective Pb detection: dual colorimetric-fluorescent sensing and mechanistic insights.
Takkar P, Negi S, Singh B … +4 more , Pani B, Bhandari M, Kakkar R, Kumar R
Spectrochim Acta A Mol Biomol Spectrosc · 2026 May · PMID 42275727 · Publisher ↗
The physiological and environmental impacts of toxic heavy metal ions have driven the development of selective and sensitive chemosensors. In this study, a pyranopyrazole-appended rhodamine B derivative (PR) was synthesi...
The physiological and environmental impacts of toxic heavy metal ions have driven the development of selective and sensitive chemosensors. In this study, a pyranopyrazole-appended rhodamine B derivative (PR) was synthesized and evaluated as a selective chemosensor for Pb detection. The probe exhibited distinct colorimetric and fluorescence "turn-on" responses upon interaction with Pb ions in both solution and solid-state systems. Spectroscopic studies indicated the formation of a stable 1:1 complex with a binding constant of 1.523 × 10 M and a detection limit of 4.392 nM. The sensing mechanism involves the opening of the spirolactam ring, which is supported by fluorescence studies and density functional theory (DFT) calculations. The probe demonstrated good selectivity in the presence of competing metal ions and showed practical applicability in real sample analysis. Additionally, the system was used to construct molecular logic gate operations. This combined experimental and theoretical investigation demonstrates the potential of PR as a multifunctional sensing platform for Pb detection.
An object-based framework for identifying moldy corn using hyperspectral images.
Niu Y, Yang Z, Tian W … +4 more , Jiang H, Zhao L, Wang X, Liu X
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42275726 · Publisher ↗
Hyperspectral imaging (HSI), leveraging its non-destructive and rapid detection capabilities, has become a pivotal technology for mold detection of corn and other grains. Currently, prevalent methodologies for grain mold...
Hyperspectral imaging (HSI), leveraging its non-destructive and rapid detection capabilities, has become a pivotal technology for mold detection of corn and other grains. Currently, prevalent methodologies for grain mold detection are broadly classified into pixel-based (PB) and kernel-based (KB) methods, but both have inherent limitations. PB methods depend only on spectral data for mold identification, ignoring spatial features and causing misclassifications of substances with similar spectra. KB methods extract overall kernel features to detect mold but overlook fine-grained corn characteristics, making it hard to capture mold features when mold pixels are scarce. To address these issues and improve the accuracy of moldy corn detection, this study proposes an innovative object-based (OB) framework for identifying moldy corn. In this framework, a Normalized Corn Mold Index (NCMI) for near-infrared (NIR) hyperspectral images is proposed to enhance the separability of healthy and moldy corn kernels. Subsequently, multiresolution segmentation partitions each corn kernel into homogeneous objects, forming a structured foundation for feature extraction. A multi-scale convolutional network (MSCNN) is then designed to extract hierarchical features from these objects, effectively capturing fine-grained details and contextual information across scales. The extracted features are fed into a support vector machine (SVM) for final classification, constructing an MSCNN-SVM model that integrates multi-scale feature extraction with discriminative classification. Experiments show our OB framework achieves 97.01% accuracy, outperforming PB and KB methods. The newly developed framework offers robust technical support for the intelligent monitoring of food quality and safety, demonstrating extensive application prospects and significant promotion value.
Fourier transform infrared spectroscopy (FTIR) for human infectious disease diagnosis, microbial identification and strain discrimination: a systematic review (2015-2025).
Kaufmann G, Boaro AP, Goergen A … +5 more , Juchem CF, Santos RO, Corbellini VA, Hoehne L, Heidrich D
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42275725 · Publisher ↗
Infectious diseases remain a persistent and evolving public health challenge, driven by factors such as antimicrobial resistance, emerging pathogens and environmental changes. In this context, this systematic review aims...
Infectious diseases remain a persistent and evolving public health challenge, driven by factors such as antimicrobial resistance, emerging pathogens and environmental changes. In this context, this systematic review aims to analyze the analytical performance of Fourier Transform Infrared Spectroscopy (FTIR) for the microbiological identification, strain discrimination and diagnosis of human infectious diseases, based on studies published between 2015 and 2025. The review followed PRISMA guidelines and included 50 articles selected from PubMed, Scopus, and ScienceDirect databases. The findings demonstrate that FTIR is a promising analytical tool for microbial discrimination, identification, and diagnosis, particularly in studies involving cultured microorganisms combined with chemometric modelling. Most studies focused on bacteria (42%) and fungi (32%), with fewer addressing viruses (20%) and protozoa (6%). Chemometric analysis played a central role in enabling FTIR applications, particularly through the integration of unsupervised methods, such as Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA), with supervised techniques like Linear Discriminant Analysis (LDA), Support Vector Machines (SVM), and Artificial Neural Networks (ANN). Most studies aimed at microbial identification (58%) or diagnosis (14%), while 28% focused on discrimination without proposing predictive models. Overall, FTIR shows strong potential as a complementary tool for rapid diagnosis and screening of infectious diseases. However, its clinical implementation still depends on further standardization, robust validation, and the development of reliable spectral databases.
Determination of turbidity in a drinking water reservoir from UV-Vis absorption spectra with multivariate modeling.
Santos I, Nunes P, Baldow MC … +5 more , Gianini E, Merhy D, Roland F, Bell MJ, Anjos V
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42275724 · Publisher ↗
This study evaluates ultraviolet-visible (UV-Vis) spectroscopy as a quantitative approach for turbidity detection in clear freshwater systems, where conventional methods often show limited sensitivity and reduced accurac...
This study evaluates ultraviolet-visible (UV-Vis) spectroscopy as a quantitative approach for turbidity detection in clear freshwater systems, where conventional methods often show limited sensitivity and reduced accuracy at low particle concentrations, particularly in reservoirs used for drinking water supply, where maintaining low turbidity is essential. Water samples were collected in 26 surface and bottom sampling sites, totaling 52 samples, along a clear water drinking water supply reservoir. The samples were analyzed using UV-Vis spectrophotometry (200-900 nm). Principal Component Analysis (PCA) was applied to identify spectral patterns, and Partial Least Squares (PLS) regression was used to develop predictive models for turbidity based on absorbance spectra. The first two PCA components explained 91% of the total variance, and clearly distinguished surface and bottom samples, indicating consistent spectral differences associated with vertical gradients. The PLS model showed a strong correlation (0.71 R) between predicted and measured turbidity, demonstrating reliable performance under low turbidity conditions. These results indicate that UV-Vis spectroscopy enhances sensitivity in clear waters and enables the detection of subtle variations in suspended particles, overcoming limitations of conventional methods. Given the contrasting results reported in the literature regarding the application of spectroscopy to water samples, this study contributes to improving the use of this technique. Also, by integrating spectral analysis with multivariate calibration, this study refines turbidity assessment in freshwater systems and advances the validation of in situ measurements, providing a non-invasive approach for water quality monitoring and sediment dynamics evaluation.
Micellization-controlled self-assembly of ZnPc(SO₂Cl)₄ in aqueous media: spectroscopic, dynamic light scattering, and DFT insights into surfactant-induced aggregation.
Jamoussi B, Gzara L, Halawani RF … +4 more , Chakroun R, Aloufi FA, Almeelbi TB, Aljohani NS
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42275723 · Publisher ↗
The aggregation behavior of zinc tetrasulfonyl chloride phthalocyanine (ZnPc (SO ₂Cl) ₄) in aqueous media was investigated using UV-Visible spectroscopy, dynamic light scattering (DLS), and density functional theory (DFT...
The aggregation behavior of zinc tetrasulfonyl chloride phthalocyanine (ZnPc (SO ₂Cl) ₄) in aqueous media was investigated using UV-Visible spectroscopy, dynamic light scattering (DLS), and density functional theory (DFT) calculations. In DMF, ZnPc(SO₂Cl)₄ exhibits well-defined Q and Soret bands, indicating the presence of predominantly monomeric species. In contrast, increasing the water fraction promoted strong π-π stacking interactions between the macrocycles, leading to H-type aggregates characterized by Q-band broadening and hypochromism. The addition of sodium dodecyl sulfate (SDS) progressively disrupted these aggregates and modulated the supramolecular organization of the phthalocyanine. Spectral evolution combined with second-derivative analysis revealed an apparent micellization threshold at approximately 7.5 mM SDS, corresponding to the transition from aggregated species to surfactant-stabilized chromophores. DLS measurements supported this behavior, showing large aggregates in the premicellar regime (≈614 nm at 4 mM SDS), a significant reduction in hydrodynamic diameter near the critical micelle concentration (≈262 nm at 7.5 mM SDS), and the formation of ZnPc-SDS supramolecular assemblies in the post-micellar regime (≈398 nm at 9 mM SDS). DFT calculations further confirmed the favorable π-π stacking in ZnPc(SO₂Cl)₄ dimers and revealed increasing binding energies for ZnPc(SO₂Cl)₄-(SDS)ₙ complexes, highlighting the cooperative role of hydrophobic and electrostatic interactions in stabilizing the assemblies.
Quantitative detection of cadmium pollution in lettuce leaves under selenium influence via fluorescence hyperspectral imaging.
Shi L, Sun J, Cong S … +6 more , Zhang B, Wu X, Dai C, Kuang Q, Ding Z, Yao K
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42269347 · Publisher ↗
Heavy metal cadmium (Cd) pollution poses a serious threat to agricultural safety, and the application of selenium (Se) to mitigate Cd stress introduces additional complexity for Cd nondestructive detection. This study in...
Heavy metal cadmium (Cd) pollution poses a serious threat to agricultural safety, and the application of selenium (Se) to mitigate Cd stress introduces additional complexity for Cd nondestructive detection. This study investigated the feasibility of employing fluorescence hyperspectral imaging (F-HSI) for detecting Cd pollution in lettuce leaves under Se influence. The raw spectra were preprocessed using savitzky-golay filter to effectively suppress noise and enhance subtle spectral features, thereby highlighting weak fluorescence spectral information. Subsequently, a multi-modal differential fusion selector (MDFS) was proposed to extract sensitive features closely associated with Cd by sorting out the complex fluorescence spectra-Se-Cd relationships under SeCd interaction conditions. Combined with a one-dimensional convolutional neural network (1D-CNN) based on the VGG architecture, the quantitative prediction model for Cd content in lettuce leaves under the background of SeCd interaction was developed. Compared with classical methods, MDFS demonstrated superior feature extraction performance in both machine learning and deep learning models, significantly enhanced the predictive capability of Cd content under Se influence. Ultimately, the 1D-CNN model built using MDFS-features achieved the highest prediction performance (R = 0.9173, RMSEP = 0.0272 mg/kg, RPD = 2.5108). In summary, the method system of F-HSI combined with savitzky-golay filter, MDFS and 1D-CNN provides a reliable approach for nondestructive detection of Cd pollution in lettuce leaves under Se influence, offering a foundation for future research on nondestructive detection of heavy metal under complex agronomic environments.
From traditional medicine to advanced sensing: A natural Fraxin-based supramolecular probe for visual pH detection and in vivo gastrointestinal imaging.
Wang L, Zhang L, Liang T … +6 more , Gao Y, Kang Z, Nan Y, Qiang Z, Wang Y, An Y
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42269346 · Publisher ↗
Dynamic monitoring of intracellular pH homeostasis is critical for revealing pathological mechanisms and enabling early diagnosis of diseases. Accordingly, the development of fluorescent pH probes with high sensitivity,...
Dynamic monitoring of intracellular pH homeostasis is critical for revealing pathological mechanisms and enabling early diagnosis of diseases. Accordingly, the development of fluorescent pH probes with high sensitivity, low-cost, and excellent biocompatibility is of considerable importance for biomedical diagnostics. In this study, a novel fluorescent probe based on a pH-induced reversible self-assembly mechanism was constructed using Fraxin, a natural small molecule extracted from the traditional Chinese medicine Cortex Fraxini. Experimental results show that Fraxin remains in a discrete state with quenched fluorescence in acidic microenvironments. As the pH increases to a weakly alkaline range, the molecules undergo self-assembly into nanosphere structures driven by π-π stacking, hydrogen bonding, and electrostatic interactions, triggering a pronounced "Off-On" fluorescence response. The probe exhibits an excellent linear correlation (R = 0.9985) within the pH range of 5.6-6.8 and demonstrates strong resistance to ambient light interference. In terms of practical applications, we developed a paper-based sensing platform for rapid screening of sulfur-fumigation in medicinal materials and established a smartphone-assisted point-of-care testing (POCT) system for digitalized pH monitoring. Regarding bioimaging, the probe demonstrates excellent cell permeability and specific mitochondrial targeting capability. In vivo studies further demonstrate its capability to monitor pH fluctuations in zebrafish and to track real-time changes in gastric acidity in mice following omeprazole treatment. Overall, this research not only elucidates the supramolecular assembly behavior of Fraxin but also provides new insights into the development of natural-sourced portable diagnostic tools and clinical gastrointestinal disease monitoring.
Salicylaldehyde-functionalized gold-nanocluster-based Ratiometric fluorescent sensor Array for metal-ion detection.
Yang X, Deng L
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42269345 · Publisher ↗
Heavy metal ions often coexist as multi-ion mixtures in aquatic environments, making their multiplex discrimination difficult for conventional fluorescent probes based on specific "lock-and-key" recognition. Herein, we r...
Heavy metal ions often coexist as multi-ion mixtures in aquatic environments, making their multiplex discrimination difficult for conventional fluorescent probes based on specific "lock-and-key" recognition. Herein, we report a dual-channel ratiometric fluorescent sensor array constructed from salicylaldehyde (SA)-functionalized, protein-stabilized gold nanoclusters (AuNCs) for the discrimination of ten metal ions (Zn, Hg, Co, Pb, Ag, Cu, Fe, Fe, Ni and Mn). The two nanocluster probes generated distinct ratiometric fluorescence response patterns toward different metal ions, providing informative fingerprints for pattern recognition. Combined with principal component analysis (PCA) and linear discriminant analysis (LDA), the sensor array allowed reliable classification of ten metal ions at concentrations as low as 0.5 μM and enabled the discrimination of multicomponent heavy-metal mixtures. More importantly, the ExtraTrees model further improved concentration-independent classification and enabled satisfactory quantitative prediction. The array also remained applicable for differentiating metal ions in real water samples, highlighting its potential for practical monitoring of multiple heavy metal ions in complex aqueous environments.
Polarity probes targeting different organelles based on aza-coumarin for monitoring ferroptosis and cellular senescence.
Ni WP, Lin Q, Xu HD … +2 more , Sun R, Ge JF
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42269344 · Publisher ↗
Polarity within the cellular microenvironment is a key physical parameter that regulates multiple biological processes, and its dysregulation is closely associated with various diseases. This work designed and synthesize...
Polarity within the cellular microenvironment is a key physical parameter that regulates multiple biological processes, and its dysregulation is closely associated with various diseases. This work designed and synthesized three polarity-sensitive fluorescent probes (3a-3c) based on an aza-coumarin fluorophore with a D-π-A structure, leveraging the intramolecular charge transfer (ICT) mechanism. The optical properties of the probes exhibited distinct solvatochromism in different solvents, with large Stokes shifts (3143, 2899, 3202 cm for 3a-3c, respectively), demonstrating excellent polarity responsiveness and biocompatibility. Colocalization experiments confirmed that, probes 3a-3c at a low concentration of 50 nM localized specifically to lysosomes, lipid droplets (LDs), and the endoplasmic reticulum (ER) with high Pearson's colocalization coefficients of 0.93, 0.98, and 0.97, respectively. In ferroptosis experiments, a marked reduction in fluorescence intensity (3.3-4.1-fold decrease) was observed for probes 3a-3c, highlighting the real-time monitoring capability of the probes. In addition, the probes also successfully distinguished polarity differences between normal and senescent cells in the cellular senescence experiment. This study thus provided a powerful tool and novel insights for elucidating the role of cellular polarity in pathophysiological processes such as ferroptosis and cellular senescence.
Benchmarking analytical parameters of chemiluminescent superoxide systems for robust quantification of graphene oxide redox activity.
Chermashentsev GR, Poimenova IA, Ovseenko ST … +4 more , Ratova DV, Proskurnina EV, Proskurnin MA, Mikheev IV
Spectrochim Acta A Mol Biomol Spectrosc · 2026 Jun · PMID 42269343 · Publisher ↗
Three chemiluminescent (CL) systems for superoxide anion radical (SAR) generation were evaluated using two probes: luminol (Lum), responsive to detecting a broad range of reactive oxygen species (ROS), and lucigenin (Luc...
Three chemiluminescent (CL) systems for superoxide anion radical (SAR) generation were evaluated using two probes: luminol (Lum), responsive to detecting a broad range of reactive oxygen species (ROS), and lucigenin (Luc), most selective to SAR. The Co(II)/HO system, in both Lum- and Luc-based assays, showed good repeatability and reproducibility (s < 15%), suitable for routine screening, whereas the enzymatic system using xanthine/xanthine oxidase (Xa/XO) provided higher SAR generation selectivity but markedly poorer reproducibility (s > 20%). An operational threshold for detectable CL response changes was estimated for the Lum/Co(II)/HO system, whereas the Luc/Xa/XO system is suitable for selective same-day SOD-referenced comparative assays. Thirty aqueous graphene oxide dispersions (aqGO), including pristine (unpurified) and purified by a dialysis bag membrane, were studied in these CL-based assays. The CL intensity decreased by 50-70% in the presence of pristine aqGO and by 80-90% with purified samples, resulting in an operational detectable-response threshold of 1-2 mg L depending on aqGO type under the Lum/Co(II)/HO protocol. Compared to SOD, aqGO exhibits antioxidant activity up to 10 times less efficiently. The obtained results show the advantages and limitations of each CL system for SAR-based antioxidant/prooxidant assessment and validate the strong modulatory role of GO. A practical quantitative criterion of inhibitory activity based on half-suppression of CL intensity (or integrated area) is proposed to evaluate antioxidant and prooxidant activity across a batch of GO samples. An approach to estimate the concentration of accessible sorption-active oxygen-containing sites is proposed. A metrological scheme for Co(II)/HO systems in both probes, standardized assessment of the "antioxidant activity" and nanozyme-like behavior of graphene-based materials, suitable for interlaboratory comparison and batch quality control, is outlined.
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