In general, many Raman measurements suffer from fluorescence, which forces the use of longer excitation wavelength (lower photon energy) lasers to prevent the fluorescence signal from overwhelming the Raman signal. However, this results in reduced sensitivity of low-cost silicon CCD detectors at higher wavenumbers, making it difficult (or impossible) to observe the “stretch” portion of the Raman spectra.
In this paper, a one-time digestion method for the determination of arsenic (As), antimony (Sb), selenium (Se), and mercury (Hg) in geological samples was established.
The study developed an effective mid-infrared spectroscopic identification model, combining principal component analysis (PCA) and support vector machine (SVM), to accurately determine the geographical origin of five types of millet with a recognition accuracy of up to 99.2% for the training set and 98.3% for the prediction set.
Accurate determination of the elemental composition of nickel-based alloys is essential, given their use in high-performance equipment. This XRF technique enables rapid and nondestructive detection, as an alternative to existing approaches.
The relationship between leaf nitrogen content (LNC) and hyperspectral remote sensing imagery (HYP) was determined to construct an estimation model of the LNC of drip-irrigated sugar beets, to enable real-time monitoring of sugar beet growth and nitrogen management in arid areas.
The possible energy transfer modes between Yb3+ and Tm3+ ions were analyzed.
An artificial neural network was combined with LIBS to provide a rapid and accurate coal-rock recognition method for unmanned coal mining.
Using Raman imaging, wild-type and engineered yeast cells were compared for their ability to produce bioactive compounds. Raman imaging microscopy is able to visualize locales, relative abundance, and production efficiencies of biologically active compounds for the individual yeast cells.
In this paper, a system based on laser induced breakdown spectroscopy (LIBS) and back propagation (BP) method was developed for the composition and traceability analysis of crop burning smoke.
A proposed solution is a coal species classification method that combines terahertz time-domain spectroscopy with machine learning - specifically, principal component analysis (PCA) and cluster analysis (CA). By using terahertz (THz) time-domain spectroscopy (TDS), the absorption coefficient, dielectric constant, and refractive index of each sample were obtained from lignite, bituminous coal, and anthracite samples.
A novel intelligent inversion model integrating multiscale fractal analysis, PCA, and machine learning techniques (RF and SVM) was devised to accurately estimate soil organic matter (SOM) using hyperspectral data.
This month’s column investigates the elemental composition of electrolytes in lithium-ion batteries (LIBs) using inductively coupled plasma–mass spectrometry (ICP-MS).
The case studies presented here successfully demonstrate the use of inline Raman spectroscopic analysis to estimate solvent content during the solvent exchange and distillation operations in the synthesis of active pharmaceutical ingredients.
An ongoing challenge within the forensic science community is the development of consistent report and testimony language that conveys results in a meaningful manner.
Graphene exhibits special properties, such as high strength and high electrical and thermal conductivity and as such is highly desirable for key electronic components. A new Raman spectroscopy sampling technique has been applied to the characterization of batches of graphene that provides a simple, at-line method for obtaining key product data.
We show how FT-IR may be used for quality control analysis of natrii sulfas, a transparent crystalline material used in natural medicine that primarily contains sodium sulfate decahydrate, crystallized from sulfate minerals.
Reliable quantitative FT-IR measurements require that the pathlength be known to within 1%. Pathlength estimations based on nominal spacer thickness are not reliable and require that the actual pathlength be measured for accurate data. We demonstrate how.
This study aimed to establish a fast, accurate method for quality evaluation of herbal medicine using NIR and chemometrics with ultraviolet-visible spectrophotometry (UV-vis) as a standard method to determine the total flavonoids content.
Analysis of 66 pesticides and 5 mycotoxins regulated by the State of California in cannabis tinctures were analyzed using LC–MS/MS with an ESI source, and LC–MS/MS with an APCI source. A simple, fast, and cheap acetonitrile solvent extraction method was used for sample preparation for good recovery and high throughput, and internal standards were used to compensate for ion suppression effects from the hydrophobic matrix.
Great interest has recently aroused in the study of the dysregulation of chemical elements within tissues. Information about the distribution of elements in biological tissues can contribute to a more complete medical diagnosis, and can guide therapeutic procedures for many pathologies.
In this study, in situ Raman spectroscopy was used to detect the formation, growth, and evolution of corrosion inside a salt fog chamber. These results pave the way for monitoring the real-time observation of corrosion on metal surfaces.
This article discusses how FT-IR and SERS is being used to detect counterfeit pharmaceutical drugs.
Utilizing a low-altitude unmanned aerial vehicle (UAV), a hyperspectral remote-sensing system can identify key grass species indicating grassland degradation, developing an ASI index and classification rules and leveraging spectral differences and plant senescence reflectance to effectively monitor and evaluate grassland conditions and degradation.
To study the optical properties of mixed crude oil, the optical constants of samples consisting of two crude oils mixed in different proportions were obtained by the double-thickness transmittance method based on transmittance spectra.