Raman spectroscopy is gaining ground in the analysis of microplastics, especially due to its high spatial resolution that allows the investigation of small plastic particles, whose numeric abundance is argued to be particularly relevant in aquatic systems. Here, we aimed at outlining the status of Raman analysis of microplastics from aquatic systems, highlighting the advantages and the drawbacks of

This paper describes a data preprocessing algorithm that can be used to mitigate the effects of interfering spectral components when the goal is to detect the spectrum of unknown components in a mixture of known components or to verify the presence of suspected components in the spectrum of a mixture of known components. The algorithm is both relatively simple and applicable to a wide range of problems

Spectroscopic signatures of cased high-explosive charge denotations are examined using emission spectroscopy with sub nanometer resolution. Eleven distinct case materials are investigated for atomic features of their major alloying elements. Molecular features of case material combustion products are also investigated for five case materials. Emission is monitored within the 275–425 nm range for atomic

The chemical composition of recent and fossil organic-walled dinoflagellate cyst walls and its diversity is poorly understood and analyses on single microscopic specimens are rare. A series of infrared spectroscopic experiments resulted in the proposition of a standardized attenuated total reflection micro-Fourier transform infrared-based method that allows the collection of robust data sets consisting

Femtosecond laser-induced breakdown spectroscopy (fs-LIBS) is employed to detect tiny amounts of mass ablated from macroscopic specimens and to measure chemical images of microstructured samples with high spatial resolution. Frequency-doubled fs-pulses (length 400 fs, wavelength 520 nm) are tightly focused with a Schwarzschild microscope objective to ablate the sample surface. The optical emission

We report the observation of photoluminescence emission from airborne gold, silver, and copper nanoparticles. A continuous wave 532 nm laser was employed for excitation. Photoluminescence from gold nanoparticles carried in a nitrogen gas flow was both spectrally resolved and directly imaged in situ using an intensified charge-coupled device camera. The simultaneously detected Raman signal from the

Studying dielectric properties of heterogeneous systems is challenged by a problem of uncertainty of the ratio between dielectric permittivity of the system and dielectric permittivities of its components. Such ratios can be obtained in some cases using theoretical effective medium models. However, such models have not yet been developed for all the systems possible. Particularly, there is no effective

Laser-induced breakdown spectroscopy (LIBS) was explored as a method of monitoring oxygen (O) concentration in electrolytic reduction salt of pyroprocessing. Simulated salt samples were fabricated, and each sample was put in a transparent and sealed vial filled with argon gas. An Nd:YAG laser pulse was applied to the sample through the vial surface, and the optical emission spectrum was measured. O(I)

The long–short double-pulse laser-induced breakdown spectroscopy (LS-DP-LIBS) method was applied to qualitative and quantitative analyses of underwater steel samples to improve the detection ability of underwater measurement. The stable plasma intensity and discrete emission lines were detected using LS-DP-LIBS when comparing the measured results of single-pulse LIBS (SP-LIBS) and LS-DP-LIBS. The long

We suggest a new modality of infrared spectroscopy termed Infrared Refraction Spectroscopy, which is complimentary to absorption spectroscopy. The beauty of this new modality lies not only in its simplicity but also in the fact that it closes an important gap: It allows to quantitatively interpret reflectance spectra by simplest means. First, the refractive index spectrum is calculated from reflectance

Raman spectroscopy is a non-invasive optical technique that can be used to investigate biochemical information embedded in cells and tissues exposed to ionizing radiation used in cancer therapy. Raman spectroscopy could potentially be incorporated in personalized radiation treatment design as a tool to monitor radiation response in at the metabolic level. However, tracking biochemical dynamics remains

There is considerable confusion when naming vibrations in infrared and Raman spectra. One of the most common errors is the identification of some stretching and bending vibrations as “asymmetric”. There are no asymmetric vibrations as such vibrations incur rotations and translations. The correct term is antisymmetric and it is demonstrated, through molecular symmetry operations, why this is the correct

In the spectral quantitative analysis of scattering solution, the improvement of accuracy is seriously restricted by the nonlinearity caused by scattering, and even the measurement will fail due to the influence of scattering. The important reasons are that the modeling variables are greatly affected by nonlinearity, and the information contained in the modeling data cannot represent the scattering

* These authors contributed equally to this work.The molecular-level insight of protein adsorption and its kinetics at interfaces is crucial because of its multifold role in diverse fundamental biological processes and applications. In the present study, the sum frequency generation (SFG) vibrational spectroscopy has been employed to demonstrate the adsorption process of bovine hemoglobin (BHb) protein

This paper describes the effects of laser pulse rate and solution flow rate on the determination of lithium at high pressure for water and 2.5% sodium chloride solutions using laser-induced breakdown spectroscopy (LIBS). Preliminary studies were performed with 0–40 mg L−1 Li solutions, at ambient pressure and at 210 bar, and in static and flowing (6 mL · min−1) regimes, for a combination of four different

Photoluminescence spectroscopy is a nondestructive optical method that is widely used to characterize semiconductors. In the photoluminescence process, a substance absorbs photons and emits light with longer wavelengths via electronic transitions. This paper discusses a method for identifying substances from their photoluminescence spectra using machine learning, a technique that is efficient in making

Surface-enhanced Raman scattering (SERS) is a powerful technique for sensitive label-free analysis of chemical and biological samples. While much recent work has established sophisticated automation routines using machine learning and related artificial intelligence methods, these efforts have largely focused on downstream processing (e.g., classification tasks) of previously collected data. While

Selenium detection and removal from industrial and mining effluents have gained attention recently due to the negative effects of this trace element on aquatic life. However, the current methods for the detection of selenium in effluents are off-line by nature. In order to fill this gap, we investigated the use of laser ablation-assisted laser-induced fluorescence (LA-LIF) to measure trace amount of

Recently there has been upsurge in reports that illicit seizures of cocaine and heroin have been adulterated with fentanyl. Surface-enhanced Raman spectroscopy (SERS) provides a useful alternative to current screening procedures that permits detection of trace levels of fentanyl in mixtures. Samples are solubilized and allowed to interact with aggregated colloidal nanostars to produce a rapid and sensitive

We have developed a compact instrument called the “COmpact COlor BIofinder”, or CoCoBi, for the standoff detection of biological materials and organics with polyaromatic hydrocarbons (PAHs) using a nondestructive approach in a wide area. The CoCoBi system uses a compact solid state, conductively cooled neodymium-doped yttrium aluminum garnet (Nd:YAG) nanosecond pulsed laser capable of simultaneously

Often only small amounts of sample are available for spectroscopic analytical determinations. This work investigates the enhancement of signal in columns packed with silica particles. We propose that silica particles cause the light to scatter through the column, effectively increasing optical path length. Packed columns are shown to be effective with fluorescence spectroscopy, but results were inconclusive

The purpose of this study was to understand the ordered structure of starch in rice flour based on a physical modification with non-heating, milling, and water sorption through the structural evaluation of rice flour using small-angle X-ray scattering (SAXS) and infrared spectroscopy within the 4000–100 cm−1 region. The SAXS pattern of the samples with low moisture contents subjected to milling yield

In this experimental research, a label-free sensing strategy is developed and employed to detect adenosine triphosphate with utilization of aptamers, including exonuclease I and SYBR Gold. The conformation of aptamers bonding to the specific target molecule (ATP) is transformed into an antiparallel G-quadruplex structure from a random coil. Afterwards, considering the unfolded aptamers are the preferred

Simple ultraviolet–visible spectroscopy-based methodology was proposed and utilized for the initial characterization of potential changes in selectivity of doped magnetic nanoparticles. Doped and undoped iron(II,III) (Fe3O4) magnetic nanoparticles were synthesized by the coprecipitation method. The doping processes of nanoparticles were confirmed using optical emission spectrometry, while the sizes

Fluorescence imaging is a major driver of discovery in biology, and an invaluable asset in clinical diagnostics. To overcome quenching limitations of conventional fluorescent dyes and further improve intensity, nanoparticle-based constructs have been the subject of intense investigation, and within this realm, dye-doped silica-coated nanoparticles have garnered significant attention. Despite their

The functionality of active centers in proteins is governed by the secondary and higher structure of proteins which often lead to structures in the active center that are different from the structures found in protein-free models of the active center. To elucidate this structure–function relationship, it is therefore necessary to investigate both the protein structure and the local structure of the

We investigated the near-infrared spectrum of piperine using quantum mechanical calculations. We evaluated two efficient approaches, DVPT2//PM6 and DVPT2//ONIOM [PM6:B3LYP/6-311++G(2df, 2pd)] that yielded a simulated spectrum with varying accuracy versus computing time factor. We performed vibrational assignments and unveiled complex nature of the near-infrared spectrum of piperine, resulting from

The global fight against mosquito-borne viral diseases has in recent years been bolstered by the introduction of the endosymbiotic bacteria Wolbachia to vector populations, which in host mosquitoes supresses the transmissibility of several viruses. Researchers engaged on this front of the battle often need to know the Wolbachia infection status of individual mosquitoes as the intervention progresses

Multidrug resistance (MDR) is highly associated with poor prognosis of chronic myeloid leukemia (CML). This work aims to explore whether the laser tweezers Raman spectroscopy (LTRS) could be practical in separating adriamycin (ADR) resistance CML cells K562/ADR from its parental cells K562, and to explore the potential mechanisms. Detection of LTRS initially reflected the spectral differences caused

Label-free molecular imaging is a promising utility to study tissues in terms of the identification of their compartments as well as chemical features and alterations induced by disease. The aim of this work was to assess if higher magnification of optics in the FTIR microscope coupled with the focal plane detector (FPA) resulted in better resolution of lung structures and if the histopathological

The ultraviolet resonance Raman (UVRR) spectra of the adenine-containing enzymatic redox cofactors nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD) in aqueous solution of physiological concentration are compared with the aim of distinguishing between them and their building block adenine in potential co-occurrence in biological materials. At an excitation wavelength of

Coherent anti-Stokes Raman scattering (CARS) spectroscopy is a powerful tool for Raman imaging technology. In contrast, conventional spontaneous Raman spectroscopy is often used for biological analysis with multivariate analysis. This study develops a new type of CARS instrument with a double-wavelength-emission background-free electronically tuned Ti:sapphire laser (DW-ETL). DW-ETL generates two laser

This focal point article discusses the developments of biomedical Raman and infrared spectroscopy, and the recent strive towards being a recognised clinical tool for various applications. The promise of vibrational spectroscopy in the field of biomedical science, alongside the development of computational methods for spectral analysis, has driven a plethora of proof-of-concept studies which convey

Melamine is a kind of small molecule compound, which has been illegally adulterated in dairy food because of the rich nitrogen content and stable chemical properties. Therefore, the detection of melamine is of great significance to food safety and human's health protection. Melamine can emit weak fluorescence, making it difficult to detect melamine directly. However melamine can significantly enhance

One of the primary objectives of planetary exploration is the search for signs of life (past, present, or future). Formulating an understanding of the geochemical processes on planetary bodies may allow us to define the precursors for biological processes, thus providing insight into the evolution of past life on Earth and other planets, and perhaps a projection into future biological processes. Several

Type II diabetes mellitus (T2DM) is a metabolic disorder that is characterized by chronically elevated glucose caused by insulin resistance. Although T2DM is manageable through insulin therapy, the disorder itself is a risk factor for much more dangerous diseases including cardiovascular disease, kidney disease, retinopathy, Alzheimer’s disease, and more. T2DM affects 450 million people worldwide

A benchtop Laser-Induced Breakdown Spectroscopy (LIBS) is demonstrated to determine the elemental carbon content present in raw coal used for combustion in power plants. The spectral intensities of molecular CN and C2 emission are measured together with the atomic carbon (C) and other inorganic elements (Si, Fe, Mg, Al, Ca, Na, and K) in the LIBS spectrum of coal. The emission persistence time of C2

Malaria is considered to be one of the most catastrophic health issues in the whole world. Vibrational spectroscopy is a rapid, robust, label-free, inexpensive, highly sensitive, non-perturbative and non-destructive technique with high diagnostic potential for the early detection of disease agents. In particular, the fingerprinting capability of Attenuated Total Reflection (ATR) spectroscopy is promising

We describe the wavelength calibration of the spectrometer for the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument onboard NASA’s Perseverance Rover. SHERLOC utilizes deep-UV Raman and fluorescence (DUV R/F) spectroscopy to enable analysis of samples from the martian surface. SHERLOC employs a 248.6 nm deep UV laser to generate Raman scattered

A linear Boltzmann plot was constructed using Cu I-lines of well-known atomic parameters. Aligning other spectral lines to the plot was adopted as a viable way to estimate the most probable values of Stark broadening parameters of Cu I-lines at 330.79, 359.91, and 360.2 nm. Plasma was generated by focusing of Nd: YAG laser radiation at wavelength 532 nm on a pure copper target in open air. Plasma emission

Discrete frequency infrared (DFIR) chemical imaging is transforming the practice of microspectroscopy by enabling a diversity of instrumentation and new measurement capabilities. While a variety of hardware implementations have been realized, considerations in the design of all-IR microscopes have not yet been compiled. Here we describe the evolution of IR microscopes, provide rationales for design

In this study, we explored the electronic structure of the surfaces of polyethylene samples having different crystallinities using attenuated total reflection (ATR)-far-ultraviolet (FUV) spectroscopy and quantum chemical calculations. Specifically, the ATR-FUV spectra of five types of high-density polyethylene (HDPE), six types of linear low-density PE (LLDPE), and seven types of low-density PE (LDPE)

A pair of ATR IR spectra obtained during the crystallization of bioplastic copolymer poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] or PHBHx from the melt by spontaneous cooling were examined using the two-trace two-dimensional correlation spectroscopy (2T2D-COS) analysis. Unlike conventional difference spectra, 2T2D spectra showed unexpected details for the patterns of spectral intensity changes

Fluorescence-based single molecule techniques, mainly including fluorescence correlation spectroscopy (FCS) and single-molecule fluorescence resonance energy transfer (smFRET), are able to analyze the conformational dynamics and diversity of biological macromolecules. They have been applied to analysis of the dynamics of membrane proteins, such as membrane receptors and membrane transport proteins

Inter- and intramolecular interactions in multicomponent polymer systems influence their physical and chemical properties significantly and thus have implications on their synthesis and processing. In the present study, chemical images were obtained by plotting the peak position of a spectral band from the datasets generated by in-situ ATR-FTIR spectroscopic imaging. This approach was successfully

A technique for analyzing IR imaging data based on two-trace two-dimensional (2T2D) correlation analysis is presented to extract pertinent information underlying spectroscopic imaging data. In 2T2D correlation mapping, each spectrum in hyperspectral data is individually compared with a reference spectrum to generate 2T2D asynchronous correlation intensity at the x- and y-coordinates on a 2T2D correlation

Determination of elemental concentrations in biological tissue is fundamental to many environmental studies. Analytical methods typically used to quantify concentrations in such studies have minimum sample volumes that necessitate lethal or impactful collection of tissues. Laser-ablation inductively coupled mass spectrometry (LA-ICP-MS) has small sample-volume requirements and offers environmental

Photoacoustic spectroscopic (PAS) detection of infrared absorption often produces spectra with enhanced intensities for weaker peaks, enabling the detection of features due to overtones and combinations, as well as less-abundant isotopic species. To illustrate this phenomenon, we present and discuss PAS infrared spectra of calcite (CaCO3). We use linearization of rapid-scan spectra, as well as comparing

In this study, one of the thermoresponsive polymers, block copolymer consisting of poly(ethylene glycol) and poly(N-isopropylacylamide), was investigated using Fourier-transform infrared (FTIR) spectroscopy, principal component analysis (PCA), and two-dimensional correlation spectroscopy (2D-COS). The apparent trend of the spectral changes in the temperature-dependent FTIR spectra of poly(ethylene

In the study of laser-induced plasmas it is customary to use the branching ratio method for assessing the conditions of optically thin plasma, which are important for the application of analytical methods such Calibration-Free LIBS. In this communication, we warn on the possibility that in some circumstances, the branching-ratio method might give results close to the one characterizing optically thin

There is a great need for the analysis of the chemical composition, structure, functional groups and interactions at polymer–metal interfaces in terms of adhesion, corrosion, and insulation. Although atomic-force-microscopy-based infrared spectroscopy (AFM-IR) can provides chemical analysis with nanoscale spatial resolution, it generally requires to thin a sample to be placed on a substrate that

Raman spectroscopy (RS) has for decades been considered a promising tool for food analysis, but widespread adoption has been held back by e.g. high instrument costs and sampling limitations regarding heterogeneous samples. The aim of the present study was to use wide area RS in conjunction with surface scanning to overcome the obstacle of heterogeneity. Four different food matrices were scanned (intact

Using the recently discovered THORS phenomenon, it is possible to generate optically induced, local density barriers in air by the absorption of intense, modulated laser light (the THORS phenomenon), which results in abrupt differences in compressibility of the air at these barriers that can efficiently reflect incident acoustic waves. In this note, we demonstrate the ability to optically manipulate

The heterogeneity of metal island films electrodeposited on conductive metal oxide modified internal reflection elements is shown to provide a variable ATR-SEIRAS (attenuated total reflection surface enhanced infrared absorption spectroscopy) response. A self-assembled monolayer of a ferrocene-terminated thiol monolayer (FcC11SH) was formed on the gold islands covering a single substrate, which was

Quartz is the most abundant mineral on the earth’s surface. It is spectrally active in the longwave infrared (LWIR) region with no significant spectral features in the optical domain, i.e., visible–near-infrared–shortwave-infrared (Vis–NIR–SWIR) region. Several space agencies are planning to mount optical image spectrometers in space, with one of their missions being to map raw materials. However,

Terahertz (THz) time-domain spectroscopy provides a direct and nondestructive method for measuring the dielectric properties of materials directly from the phase delay of coherent electromagnetic radiation propagating through the sample. In cases when crystals are embedded within an inert polymeric pellet, the Landau, Lifshitz, and Looyenga (LLL) effective medium model can be used to extract the intrinsic

We describe the fabrication of an underwater time-gated standoff Raman sensor, consisting of a custom Raman spectrometer, custom scanner, and commercial diode-pumped pulsed 532-nm laser all located inside pressure housing. The Raman sensor was tested in the laboratory with samples in air, a tank containing tap water and seawater, and in the coastal Hawaiian harbor. We demonstrate our new system by