Peer-reviewed Articles

Infrared and Raman bands are typically described in terms of peak location and peak height. The shape of the peak-its form, width, and asymmetry-is less well understood. Bandshapes largely depend upon interactions between vibrating molecules and their environment. An understanding of this relationship may enhance spectral interpretation and can explain unexpected behaviors, in both qualitative and quantitative analyses. This paper presents basic concepts that influence line shapes and shows the complex lineshape changes in an apparently simple system of acetone and water.

High stability Fourier transform-infrared (FT-IR) interferometers make it possible to conduct experiments designed to identify subtle sample structure changes resulting from external perturbations. In particular, IR spectrum measurements obtained while heating samples can be used to associate specific structure changes with incremental additions of thermal energy. This paper describes the application of variable temperature diffuse reflection infrared Fourier transform spectroscopy (VT-DRIFTS) for analysis of benzoic acid adsorbed on montmorillonite clay. The technique described here is generally applicable for soil adsorbate characterization studies, and therefore should be useful for elucidating soil transport mechanisms for selected contaminants.

Raman spectroscopy is applied to quality control of agricultural products with greater frequency, and can also be used to refine regulatory criteria for both agricultural and environmental monitoring. It is now integrated into everything from hand held SERS detectors to unmanned aerial vehicles to monitor the gamut from genetic variation to soil and water content. Development opportunities, particularly with bundled technologies, continue to emerge as demand for quality assurance increases.

Surface-enhanced Raman scattering (SERS) has been applied to the determination of the antioxidant butylated hydroxyanisole (BHA), commonly used in fatty foods and oils to prevent their oxidation. The use of SERS-Raman microscopy with an inexpensive homemade silver substrate allowed the direct determination of BHA in oils without any sample handling. Several edible and essential oils (used as flavorings) have been considered for this purpose.

Zinc telluride films doped with gadolinium (ZnTe:Gd)-made by laser ablation and deposition-have been characterized by X-ray photoelectron spectroscopy (XPS) to determine the molecular species of the elements in the material and their presence as intentionally formed contaminants.

An interlaboratory comparison study for the measurement of arsenic species in rice, kelp, and apple juice was carried out. The purpose of the study was to enable participating laboratories to evaluate their analytical capability to determine inorganic arsenic, arsenite, arsenate, monomethylarsonic acid, and dimethylarsinic acid, assess the intercomparability of the data generated, and look for any correlation trends between the results and the analytical procedures used.

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.

Dispersion of surface polaritons in zinc phosphide (Zn3P2) single crystals is presented in this article for the first time. Surface polaritons in Zn3P2 were excited using the attenuated total reflectance (ATR) method.

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.

A method for removing fluorescence-induced backgrounds from Raman spectra using sequentially shifted excitation (SSE) is described. The method uses a temperature-tuned, distributed Bragg reflector diode laser to produce the multiple excitation spectra required to implement the SSE algorithm. Examples applying the SSE method to analysis of motor oils and edible oils are given.

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.

This study describes a validated spectrofluorometric method for the analysis of L-amlodipine in tablets.

Examples are shown that highlight how elemental fingerprinting could provide valuable information about the geographical origin of a food or beverage as well as how different steps in the production of wines impact their elemental composition.

Determination of trace metals in oil and petroleum typically is based on ICP-OES methods, requiring signficant sample preparation and expensive instrumentation. This article presents an alternative method, based on the use of a handheld energy-dispersive X-ray fluorescence analyzer, that involves minimal sample preparation, uses authentic standards for calibration, gives low parts-per-million detection limits, and provides significant time and cost savings.

This article describes measurements of isotopes of hydrogen, boron, carbon, nitrogen, oxygen, and chlorine using laser ablation molecular isotopic spectrometry (LAMIS).

This article provides a basic overview of the capabilities of transmission gratings optimized for molecular spectroscopy.

Here, hyperspectral imaging was used to simultaneously estimate chlorophyll and water content of Gannan navel orange leaves.

In this study, regression and classification chemometrical algorithms were combined to achieve effective discrimination of pure body fluids from their binary mixtures.

A summary of the efforts to study microorganism biofilms using surface-enhanced Raman scattering, a powerful technique for in situ analysis of biological molecules and biomolecular organizations

Fourier transform infrared (FT-IR) spectroscopic imaging is a highly versatile technique that can be applied to a wide range of systems. This article summarizes some of the recent efforts developing applications of FT-IR imaging for microfluidics. The main advantage of FT-IR imaging compared to traditional imaging methods is that it is a label-free imaging technique.

Fourier transform infrared (FT-IR) spectroscopic imaging is a highly versatile technique that can be applied to a wide range of systems. This article summarizes some of the recent efforts developing applications of FT-IR imaging for microfluidics. The main advantage of FT-IR imaging compared to traditional imaging methods is that it is a label-free imaging technique.