Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy最新文献

Nonylphenol polyethoxylate (NPEO) and its primary metabolite nonylphenol (NP) are novel endocrine disrupting compounds and emerging pollutants, resulting in hazards toward human health. Developing a portable, ultrasensitive and rapid detection method toward NPEO and NP is a great significance for protecting human health. Here, a Python-assisted intelligent capillary imprinted fluorescence platform based on bimetallic nanozymes was developed for rapid microvolume analysis NPEO and NP. Interestingly, manganese with enzyme-like activity was introduced into iron metal organic framework (Fe-MIL(53)) to bring out a superior catalytic activity of Fe/Mn bimetallic nanozyme (Fe/Mn-MIL(53)). A nanozyme fluorescence imprinted polymer (B-CDs@Fe/Mn-MIL(53)@MIP) was prepared by one-pot method with blue carbon dots (B-CDs) as fluorescence source and NPEO as the template. Red carbon dots (R-CDs) and B-CDs@Fe/Mn-MIL(53)@MIP mixture solution was inhaled into a capillary to develop a dual-nanozyme capillary imprinted sensor. A good linear relationship existed between the fluorescence ratios of F₄₄₄/F₅₅₁/F₆₇₉ with NPEO and NP concentrations within the ranges of 0.01 nM - 110 nM and 0.01 nM - 90 nM, respectively. Additionally, the Python-assisted fluorescence imprinted capillary sensor was developed for the rapid intelligent detection of NPEO and NP with the detection limit of 0.0025 nM and 0.003 nM, respectively. The Python-assisted fluorescence imprinted capillary sensor achieves ultrasensitive microanalysis (18 μL/time) of NPEO and NP in real water samples, providing an alternative determination strategy for NPEO and NP in the environment.

Safe drinking water monitoring requires inexpensive, on-site tools that can sensitively quantify multiple inorganic anions in complex matrices. We report an integrated, low-cost (<$80) portable fluorescence sensor with the dual-responsive coumarin probe for the quantitative sequential detection of cyanide and fluoride. The device consists of a 405 nm micro-laser as a light source along with AS7265x multispectral detector and ESP32 based microcontroller. Using this device, we achieved the LOD value of 0.08 ppm for cyanide and 0.02 ppm for fluoride with robust linear calibrations (R² = 0.995 and 0.991, 1-10 ppm), Machine-learning regressors further compensated matrix and co-analyte effects, and pH/interference studies (common cations/anions, pH 6-8) validated field-relevant support. We employed the open-source hardware, a solvent-tuned sequential assay, and data-driven quantification, made the device as a good chemo sensor and the device is the first of this kind for portable fluorescence sensor developed for the fluoride and cyanide with the superior LOD values and it can be extendable for making of device for various toxic molecules and ions.

The Shixi block, located on the eastern margin of the Ordos Basin, hosts significant tight sandstone gas resources. However, the timing and processes of gas accumulation in this area remain poorly understood. In this study, we integrate detailed fluid inclusion analyses with burial and thermal history modeling to reconstruct the hydrocarbon accumulation history. Thirty-six tight sandstone samples from the Carboniferous-Permian coal-bearing strata in nine wells were analyzed using petrography, microthermometry, laser Raman spectroscopy, paleo-pressure estimation, and stable carbon isotope techniques. The results indicate the widespread occurrence of hydrocarbon-bearing aqueous inclusions, gas inclusions (CH₄ and CO₂), bitumen inclusions, and minor oil inclusions hosted mainly in quartz grains and fractures. The homogenization temperatures and salinities of aqueous inclusions range from 128.6 °C to 186.3 °C and from 0.88% to 22.17%, respectively, suggesting a relatively unified paleo-fluid system. Trapping pressures of CH₄ inclusions vary from 33.09 to 71.71 MPa, indicating significant fluid overpressure during hydrocarbon charging. The methane carbon isotopic compositions (δ¹³C₁) of inclusion gases range from -41.2‰ to -33.7‰, which are markedly lighter than those of the produced reservoir gas, implying a genetic contribution from sapropelic organic matter and secondary cracking of crude oil. Burial-thermal history modeling reveals three major hydrocarbon charging events: an initial oil charge during the Late Triassic, a subsequent oil-gas charge accompanied by oil cracking near the end of the Late Triassic, and a main phase of natural gas charging stage from the Late Jurassic to Middle Jurassic. These results provide new insights into the accumulation mechanisms and dynamic evolution of tight sandstone gas in the Shixi block.

Knee osteoarthritis (KOA) is a prevalent chronic degenerative joint disorder hallmarked by progressive cartilage deterioration, localized inflammation, and declining joint mobility. Current approaches for evaluating therapeutic outcomes rely mainly on invasive methods that preclude longitudinal monitoring, or macroscopic imaging techniques that lack molecular-level biochemical specificity. To bridge this gap, we present a compact Resonance Scanning Confocal Raman Spectral Imaging (RSCRSI) system capable of non-invasive, real-time monitoring of biochemical tissue alterations throughout KOA treatment. This platform delivers a high spectral resolution of 0.29 nm alongside a lateral spatial resolution of 2.19 μm. We applied RSCRSI to monitor the efficacy of magnesium containing gelatin-methacryloyl microspheres (G-Mg) as a model therapeutic agent for KOA. Raman spectral biomarkers were quantified in vivo using characteristic vibrational bands, including cytochrome-related peaks at 1580 cm^-1 (mitochondrial redox state indicators), hydroxyapatite ν1-PO4^3- at 956 cm^-1 (mineralization), and collagen-associated peaks at ∼1452 and 1650 cm^-1. Raman spectral imaging of the gastrocnemius muscle and tibial cartilage in KOA rats demonstrated that G-Mg treatment successfully reduced mitochondrial oxidative stress, attenuated inflammatory signals, preserved collagen spectral features, and minimized subchondral mineral exposure. Therapeutic efficacy was further corroborated by microcomputed tomography (Micro-CT). This study establishes the compact RSCRSI system as a robust platform providing real-time, spatially resolved biochemical feedback for monitoring KOA therapies in vivo. Using novel G-Mg microspheres as a representative model, we directly visualized the treatment response, including reduced oxidative stress and cartilage preservation, providing a new paradigm for the precision management of KOA.

High-sensitive detection of extracellular pH is prerequisite for finding the abnormality of several serious diseases at early stage and clarifying their pathogenesis. However, the present fluorescence pH probes were deficient in sensitivity to accurately detect extracellular pH. Here, we fabricated a high-sensitive ratiometric fluorescence pH probe, SiRho-F-pH, through the click reaction between a Si-rhodamine and a fluorescein, which had the opposite pH-responses. Upon 450 nm light excitation on the spectrometer, the ratio R_680/520 of fluorescence intensities of SiRho-F-pH at 680 nm and 520 nm changed by 1065-fold in the pH range of 4.57-9.33. While, SiRho-F-pH possessed the excellently reversible pH-response, high pH-selectivity, favorable biocompatibility, and ability to target the detection of extracellular pH. The microscope imaging at fixed cells stained with SiRho-F-pH showed that the ratio R/G of fluorescence from red and green channels changed by a notable 4858-fold in the pH range of 5.00-8.00 under 488 nm laser excitation. The mouse brain slice imaging further demonstrated that SiRho-F-pH could clearly reveal tiny changes of extracellular pH in the pH range of 6.61-6.71 with micrometer spatial resolution. The ratiometric fluorescence mode of SiRho-F-pH could be used to detect the extracellular pH with high sensitivity and spatial-resolution.

Metal-organic frameworks (MOFs) offer significant potential for tunable luminescence due to their structural versatility. This study investigated the MOFs (Bio-MOF-1-Me) with an anionic structure, which exhibited extremely strong intrinsic ultraviolet fluorescence. To achieve color tunability, Bio-MOF-1-Me undergoes ion exchange with cationic dyes 4-[p-(dimethylamino)styryl]-1- ethyl-pyridinium iodide (DASEPI) and acriflavine (AF). Structural characterization (PXRD, IR) confirms framework integrity post-exchange and reveals dye incorporation via electrostatic interactions and π-stacking, ensuring uniform dispersion within the pores. By precisely controlling dye type and loading, the host-guest composites exhibit tunable emission colors (red, green, yellow) under 455 nm blue light excitation. This work demonstrates how host-guest structural synergy within MOFs enables controlled multicolor luminescence.

A novel spectrofluorimetric method for sensitive mirtazapine determination was developed based on fluorescence quenching of nitrogen and phosphorus co-doped carbon quantum dots (N,P CQDs). The N,P CQDs were synthesized via microwave-assisted hydrothermal treatment and comprehensively characterized using dynamic light scattering, transmission electron microscopy, FTIR spectroscopy, and fluorescence spectroscopy, revealing uniform nanoparticles (3.57 ± 1.94 nm) with high quantum yieldand optimal excitation/emission wavelengths at 360/435 nm. Subsequently, mechanistic investigations through UV-visible spectroscopy, temperature-dependent fluorescence studies, and quantum mechanical calculations confirmed static quenching via ground-state complex formation. Stern-Volmer analysis revealed high association constants (Ka = 4.20 × 10⁵ M^-1 at 298 K) with negative temperature dependence, while thermodynamic studies indicated spontaneous binding (ΔG = -32.09 kJ/mol) driven by favorable enthalpy and entropy contributions. Quantum mechanical calculations demonstrated specific interactions through hydrogen bonding and electrostatic interactions between phosphonic acid functionalities and mirtazapine's protonated tertiary amine. Following mechanistic elucidation, Box-Behnken experimental design optimized critical parameters (pH 5.5, N,P CQDs concentration 26 μg/mL, reaction time 4 min) achieving maximum quenching efficiency. The validated method demonstrated excellent analytical performance with linear range 0.05-3.0 μg/mL (r² = 0.9998), detection limit 0.016 μg/mL, quantification limit 0.049 μg/mL, accuracy 98.78 ± 1.393%, and precision RSD values below 2%. Furthermore, statistical comparison with reference HPLC method confirmed equivalent performance (t-test p = 0.844, F-test p = 0.759). Recovery studies in pharmaceutical formulations and environmental water samples (river and tap water) yielded 96.27-104.46% recoveries with RSD < 4%, demonstrating broad method applicability. Finally, green chemistry assessment using AGREE (0.72), BAGI (77.5), and RGB12 (89.0% whiteness) tools confirmed superior sustainability compared to conventional methods. The developed method offers a cost-effective, environmentally friendly alternative for routine mirtazapine analysis in pharmaceutical quality control and environmental monitoring, addressing the growing need for sustainable analytical approaches while maintaining excellent analytical performance.

The Ahmed El Hansali reservoir, located in the upper Oum Er-Rbia watershed, is a strategic resource for drinking water and irrigation in the semi-arid Middle Atlas region in Morocco. It is supplied by two tributaries with contrasting inputs. The Oum Er-Rbia River, which receives urban discharges from the Srou water course over a long transport distance (∼15-20 km), and the Ouaoumana stream which conveys urban effluents over a short hydrological pathway (∼5 km). This hydrological setting creates marked spatial heterogeneity in the reservoir water sources and quality. As dissolved organic matter (DOM) is important for determining the chemical properties of natural waters, studying its optical properties could provide valuable information about the sources of organic matter and the processes by which it is transformed. Hence, in the present case, a set of eighty (80) water samples collected across the reservoir were analyzed using UV-visible absorption and fluorescence excitation-emission matrices (EEMs). Optical indices (E2/E3, E2/E4, FI, BIX and HIX), together with the IC/IT fluorescence ratio and principal component analysis (PCA), revealed large differences at the tributary inlets and gradual homogenization within the reservoir, while an anthropogenic imprint persists at the effluent. This study demonstrates that combining absorption and fluorescence spectroscopy with chemometric analysis provides an effective and widely applicable approach for probing the composition and transformation of dissolved organic matter in complex aquatic systems, particularly in contexts where molecular-level analyses are not readily accessible.

The sulfur oxidation axis is a core component of the body's sulfur metabolic network, governing the directional interconversion of sulfur species and maintaining metabolic homeostasis. Disruption of this axis can result in the accumulation of toxic intermediates or impaired biosynthetic disorders, both of which are implicated in a range of various diseases. As a central hub in sulfur metabolism, sulfite represents a critically metabolic junction linking upstream reduced sulfur species to downstream oxidized products. However, traditional analytical approaches rely on tissue homogenization, precluding the resolution of sulfite dynamics in vivo spatiotemporal precision. Although fluorescent probes for sulfite detection have been reported, most suffer from limitations in response speed, emission wavelength or biological applicability. To overcome these challenges, we developed three sulfite-responsive fluorescent probes-PNS, QNS and DNS, and systematically evaluated their performance. Among them, DNS emerged as the optimal candidate, exhibiting an ultra-rapid response time (< 2 s) in aqueous media, near-infrared emission at 700 nm for enhanced tissue penetration and excellent selectivity and biocompatibility. Using DNS, we demonstrated in living HepG2 cells that cysteine (Cys) serves as a precursor for sulfite, which is subsequently oxidized to sulfate. Notably, leveraging the superior photophysical properties of DNS, we achieved rapid dynamic tracking of sulfites in a living mouse model. Collectively, this work establishes essential technical support for in vivo sulfite visualization and provides critical technical support for elucidating the physiological functions of sulfite and the pathological mechanisms associated with dysregulated sulfur metabolism.

The influence of amine-based donors (diphenylamine, carbazole, pyrrolidine, and diethylamine) on the photophysical properties of thiazolidine containing cyanoacrylic acid photosensitizers was studied using density functional theory (DFT) calculations. Two low energy conformers, AALX and AAHX were obtained from the potential energy surface scan and their structural stability was analyzed. The absorption maxima of all the designed dyes exhibited intramolecular charge transfer (ICT) characteristics. Compared to the gas phase, in the solvent medium, the absorption has red shifted and the diphenylamine dye shows a maximum oscillator strength at a longer wavelength than the other dyes, irrespective of the conformers. The orbitals energies and chemical descriptors highlight the donor's contribution in enhancing the interaction of dyes with the surrounding electrolyte. On anchoring dyes over titania, the AAHX conformers have displayed favourable coupling of FMOs for ICT transitions. Photovoltaic parameters such as light harvesting efficiency, electron injection and regeneration, excitation energy and electron-hole pair binding energy further substantiate the function of amine donors in developing a high-performance organic sensitizer. These results elucidate the electronic features governing the photophysical aspects of a dye that enable advancement of sustainable and efficient dye-sensitized solar cells.