Journal of Raman Spectroscopy最新文献

The residues of crystal violet (CV) in shrimp were easily absorbed by biological tissues and caused serious damage to human health. In this study, doped TiO₂ SERS substrates were fabricated with three doping metals including Fe, Cu, and Co by sol-hydrothermal method. The SERS intensities reached the optimum at a Fe³⁺ doping ratio of 5% with probe molecules of 4-MBA and CV. The 5% Fe-TiO₂ SERS substrates for monitoring CV residues obtained the best performance with LOD of 0.016 ppm and 0.03 ppm for standard solutions and shrimp protein extract solutions, respectively. The results indicated suitable doping metals could effectively modulate the energy bands of the semiconductor and improve the charge transfer between the substrate and analyte for a stronger SERS signal. The study would enrich the SERS technique for the fast test of CV in the actual samples.

Molybdenum chalcogenides are one of the most studied layered materials. They have hexagonal symmetry in the single layer case as many other van der Waals materials. Thus, they can serve as a model for the analysis of many physical properties, in particular the phonon modes, the appearance of new low wave number modes when going from the single layer to the bulk, the existence of a flexural acoustic mode and the grouping of the optical modes into pairs whose difference comes from the interlayer coupling. In this work, to address some of these points, we have calculated the phonon dispersion of MoS$�{}_{�2�}$, MoSe$�{}_{�2�}$, and MoTe$�{}_{�2�}$ in bulk and in a single layer using Density Functional Perturbation Theory and discuss the evolution of the energy branches along the different directions of the Brillouin zone. The calculated values are in very good agreement with Raman data reported in the literature. We have also calculated the static and optical dielectric constants, as well as the reflectance, which has been compared with available infrared reflectance data available in the literature. Finally, we discuss the activity of the optical modes in the bulk and single layer case.

Carbonaceous materials (CMs) in black-shale rock specimens from the Kular Range, Sakha Republic, Yakutia, Russia, were investigated by micro-Raman spectroscopy. Studies of CM in Permian rock samples from the Ulakhan-Sis anticline collected from various boreholes in the Kular gold-bearing area, and CM in nodular monazite (NM) samples from alluvial sediments of different creeks of the Yana River basin revealed similar spectral features. Micro-Raman spectra excited at a wavelength of 532 nm exhibited characteristic CM bands together with bands of quartz, muscovite, anatase, rutile, carbonate, and pyrite. In the first-order Raman spectra of CM, G-bands were observed in the wavenumber range of ~1584–1597 cm⁻¹, and D1 bands at ~1347–1351 cm⁻¹ for black shale specimens, whereas for NM, G bands appeared between ~ 1572 cm⁻¹ and 1594 cm⁻¹, and D1 bands between ~1340 cm⁻¹ and 1351 cm⁻¹. NM grains consist of monazite containing numerous mineral inclusions of various sizes (from several to 10–20 μm). The Raman spectral characteristics of these associated minerals are discussed. Temperature ranges for metamorphic transformations derived from the Raman data are estimated to be 300–360 °C for CM bedrock and 346–430 °C for CM NM.

Renal failure (RF) is a progressive disorder characterized by incurability, elevated morbidity, and increased mortality, frequently affecting the adult population, particularly individuals diagnosed with diabetes and hypertension. In this paper, a rapid, easy, and non-invasive diagnostic technique, surface-enhanced Raman spectroscopy (SERS), is discussed for the screening of RF using blood serum samples with elevated creatinine concentrations. Silver nanoparticles (AgNPs) were employed as SERS substrates to enhance the Raman signals of biomolecules present in the serum samples. For this purpose, serum samples from healthy/control individuals and RF patients with varying creatinine concentrations were used for SERS spectral measurements. The diagnostic capability of SERS was further improved by applying multivariate analysis techniques such as principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA) to evaluate the potential of SERS for differentiating and classifying healthy and RF blood serum samples. Moreover, partial least-squares regression (PLSR) was used to predict unknown creatinine concentrations in RF serum samples, yielding coefficients of determination of 0.9395 mg/dL for calibration and 0.9561 mg/dL for prediction/validation. The associated errors included a root mean squared error of calibration (RMSEC) of 0.6977 mg/dL and a root mean squared error of prediction (RMSEP) of 0.8595 mg/dL. This study demonstrates that SERS, combined with multivariate analysis, is a valuable tool for the effective diagnosis of RF.

A stainless steel mesh loaded with silver nanoparticles (SSM/Ag) was developed as a low-cost and high-performance flexible surface-enhanced Raman spectroscopy (SERS) substrate for residual detection of methylene blue (MB) on curved samples. The sensor's performance was systematically investigated using rhodamine 6G (R6G) as a target molecule. The SSM/Ag substrate showed a limit of detection (LOD) of 10⁻⁸ M and an enhancement factor (EF) of 1.4 × 10⁶. The experiment also utilized the SSM/Ag substrate to detect MB residues by wiping Alternanthera philoxeroides leaves, immersing river water samples, and performing in situ detection of the delivery label on the cup body. The results showed that the limits of detection (LODs) for these three cases were 10⁻⁶, 10⁻⁷, and 10⁻⁷ M, respectively, exhibiting a reproducibility relative standard deviation (RSD) below 12%. This provides strong evidence for the validity and feasibility of the SSM/Ag substrate for in situ detection of MB residues on curved samples.

Organic memristors (OMEMRs) based on biopolymeric matrices functionalized with silver nanoparticles (AgNPs) are emerging as promising candidates for next-generation non-volatile memory technologies, owing to their multilevel resistive switching behavior, scalability, and compatibility with solution-processable fabrication methods. In this study, AgNPs were coordinated with chondroitin sulfate (ChS) to produce Ag@ChS-based OMEMRs, which were fabricated via spin-coating and subjected to a comprehensive thermal stability assessment using temperature-resolved Raman spectroscopy over the 25°C–275°C range. The Raman spectra revealed a prominent vibrational mode at 76 cm⁻¹, attributed to AgNP lattice dynamics, along with a distinct Ag–O stretching feature near 240 cm⁻¹, indicative of coordination with carboxylate groups within the ChS matrix. A marked attenuation of sulfate-associated Raman bands was observed at approximately 175°C, signifying a critical degradation threshold associated with desulfation, interfacial breakdown, and irreversible loss of memristive functionality. These findings demonstrate that Raman spectroscopy provides a sensitive, non-destructive platform for probing thermally induced molecular transformations and diagnosing early-stage failure in biopolymer-based memristive systems. The insights gained herein offer valuable guidance for the rational design of thermally robust organic memory devices.