Label-free imaging using intrinsic signals can be used to examine the behavior of molecular species in live cells, and vibrational imaging is an informative technique because each molecule has a distinct vibrational fingerprint. Ji-Xin Cheng is a Professor of Biomedical Engineering, Chemistry, and Electrical and Computer Engineering at Purdue University. He is the recipient of the 2015 Coblentz Society Craver Award, which recognizes young individuals who have made significant contributions in applied analytical vibrational spectroscopy. Prof. Cheng and his group develop such label-free spectroscopic imaging technologies to monitor cellular states on a microsecond scale and to diagnose lipid-laden plaques in cardiovascular diseases. He recently spoke to us about two of his recent studies.
Macro attenuated total reflection FT-IR spectroscopic imaging is a powerful and underutilized tool. This article presents an overview of approaches and opportunities for using this method to study dynamic processes such as diffusion, sorption, crystallization, and dissolution.
Resonance-enhanced atomic force microscopy (AFM)–infrared (IR) is a new technique that couples an atomic force microscope with a pulsed tunable IR laser source to provide high spatial resolution chemical analysis of samples as thin as a monolayer. The AFM probe tip acts as a small local detector of the thermal expansion of the sample caused by the absorption of the monochromatic IR radiation.
The mechanical properties of polymer films such as tensile strength and resistance to tearing depend strongly on the orientation of the polymer chains. Fourier transform infrared (FT-IR) spectroscopy can be used to measure the degree of orientation both within the plane of the film and normal to it.
Counterfeit and illicit tobacco may contain potentially toxic organic impurities that result in adverse health effects to the consumer. The aim of this work was to investigate the feasibility of the identification of organic impurities in counterfeit or illicit tobacco using attenuated total reflectance-Fourier transform infrared (ATR-FT-IR) spectroscopy.
Law enforcement relies upon "schedules" or lists of controlled substances. In an attempt to circumvent the law, clandestine laboratories produce synthetic designer drugs that are chemically related to a controlled substance, but are different enough to raise legal issues with prosecution.
Locate particles, generate size or shape statistics, select particles based on size or shape, and acquire Raman spectra. Easily locate and identify particulate matter, including pharmaceutical materials, trace forensic evidence, geological rock or mineral particles, and airborne contaminants trapped on filters.
Resonance and off-resonance Raman spectroscopy and imaging are used to examine the spatial variation of the solid-state structure and electronic character of few-layer MoS2 flakes. Simultaneous acquisition of photoluminescence spectra with the Raman scattering provides complementary ways of rendering Raman and photoluminescence spectral images of thin-film MoS2.
This article provides a basic overview of the capabilities of transmission gratings optimized for molecular spectroscopy.
Simulated leaf spectral data were generated to analyze scattering impact and then compared to experimental data to validate the conclusions of the simulation.
The wavelet packet transform (WPT) combined with the modified uninformative variable elimination (MUVE) method (WPT–MUVE) is proposed to select variables for multivariate calibration of spectral data.
The development of a method for the simultaneous determination of glycine, triglycine and fructose using UV–vis and evaporative light-scattering detection (ELSD) is described. This was necessary as part of a research project dealing with the recovery of functional peptides from aqueous streams on an industrial scale using adsorption or related technologies. Fructose is barely detectable by UV–vis as it lacks detectable functionalities, while glycine and triglycine are both UV–vis sensitive. An NH2 phase was chosen as a column and separation was obtained within seven minutes on a 250 X 4.6 mm column. Limits of detection are approximately 40 mg fructose/L, 4 mg glycine/L and 0.05 mg triglycine/L. Calibration functions are linear in a range of 40–1400 mg/L for fructose, 5–200 mg/L for glycine and 0.5–70 mg/L for triglycine.
An interlaboratory comparison study for the measurement of arsenic species in rice,kelp, and apple juice was carried out
The analysis of seals, mostly via the ink types, can provide evidence to authenticate the related documents and can play a key role in legal cases. In the present study, a method to discriminate red seal inks using Raman microscopy and Fourier transform infrared (FT-IR) spectroscopy was developed.
Zinc oxide levels in cosmetic formulations are commonly analyzed by atomic absorption (AA) spectroscopy using the fusion method for sample digestion, a labor-intensive and time-consuming process that causes lengthy delays in product manufacturing.
A method for the multielemental determination of metals and nonmetals in goji berries (Lycium barbarum L.) by axially and radially viewed inductively coupled plasma-optical emission spectrometry (ICP-OES) is presented.
The Gordon F. Kirkbright bursary award is a prestigious annual award that enables a promising student/non-tenured young scientist of any nation to attend a recognised scientific meeting or visit a place of learning.
Bivalves, such as clams, frequently are used as bioindicators to assess coastal aquatic environments because they can accumulate trace metals and other substancesâup to 100 times higher than the concentration levels found in the water in which they live, including elements such as chromium, lead, arsenic, and cadmium, which can be toxic even at low concentrations. Given that many bivalves are consumed by people, this bio-accumulation presents food safety as well as environmental risks.
Researchers at Monash University (Melbourne, Australia) used electron paramagnetic resonance (EPR) spectroscopy and in vitro antiradical assays to study the radical content and antiradical capacity of Coffea arabica sourced from an industrial roasting plant.
Rare earth elements (REEs) have become indispensable in many electronic, optical, magnetic, and catalytic applications because of their specific properties such as magnetism and phosphorescence, as well as their ability to both donate and accept electrons.
This article compares several performance criteria such as full width at half maximum, background equivalent concentrations, limits of detection, purge requirements, and results for some substances for the "traditional" As lines at 188.979, 193.696, and 197.197 nm for the "new" line at 228.812 nm.
A novel approach to handling samples with very high and variable levels of sample matrix is to use aerosol dilution, whereby the amount of sample aerosol that reaches the plasma is reduced by dilution with an additional argon gas stream.
By Spectroscopy Editors
Multiple-collector inductively coupled plasma–mass spectrometry (MC-ICP-MS) has some specific advantages over traditional ICP-MS instruments.
By David Gunn
Low-level analysis of food matrices has placed a demand on manufacturers, testing laboratories, and instrumentation vendors worldwide. Stricter regulations, better analytical instrumentation, and greatly improved sample preparation (preanalytical) techniques have focused efforts to simplify and standardize these analyses.
A multiresidue method has been developed and validated for the analysis of methylxanthines (caffeine and its metabolites) and cotinine in human plasma.
This article describes the development of a new data-independent acquisition (DIA) workflow for protein quantification that uses a mass spectrometer that combines three types of mass analyzers to achieve lower limits of detection (LOD), higher sensitivity, more accurate quantitative results, wider dynamic range, and better reproducibility than existing high-resolution accurate-mass (HRAM) tandem mass spectrometry (MS-MS) DIA workflows.
In most countries, herbal medicinal products (HMPs) are introduced into the market without proper scientific evaluation or enforced safety and toxicological studies.
Worldwide trends in illicit drug use and production have shifted toward an increase in synthetic analogues and the emergence of new variations in their manufacture.
By Spectroscopy Editors
We recently spoke to Gary Duncan and Wendy Russell of the Rowett Institute of Nutrition & Health in Aberdeen, Scotland, about the significance of phytochemical bioavailability to human health and the important role of liquid chromatography linked to tandem mass spectrometry (LC–MS-MS) in their research.