Infrared (IR) Spectroscopy

Igor K. Lednev at the University at Albany SUNY in New York explains advances in forensic analysis using a variety of chemometrics techniques to classify ATR FT-IR and Raman spectra of bodily fluids.

Infrared nanoscopy is a valuable new spectroscopy tool for exploring the nanoscale of materials science. Mun Seok Jeong of Sungkyunkwan University in Korea explains.

Inline FT-NIR and offline terahertz Raman imaging analysis are used to characterize active pharmaceutical ingredient (API) crystallinity and to monitor different solid physical states of the API, to control process parameters of hot melt extrusion.

Resonant SEIRA overcomes the limitations of traditional Fourier transform infrared (FT-IR) spectroscopy for minute sample sizes of relatively low absorptivity. Frank Neubrech of Heidelberg University is exploring resonant SEIRA in applications such as monitoring dynamic processes and hyperspectral infrared chemical imaging.

Polymers contain practically every infrared functional group imaginable. Now that we understand infrared functional groups from previous articles, it is time to look at the spectra of polymers in greater detail.

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.

Determining the components in a mixture can be a significant challenge in infrared spectroscopy, but spectral subtraction can help. We show the proper way to perform spectral subtraction, and the pitfalls to avoid.

Fran Adar is the winner of the 2021 Gold Medal Award from the New York and New Jersey Society of Applied Spectroscopy (SAS).

One of the biggest practical limitations of infrared spectroscopy is its difficulty in analyzing mixtures. Infrared library searching can help, but it must be done right.

The application of data mining combined with data fusion of Raman and mid- infrared spectra was studied to improve discrimination ability for modeling the geographical origins of rice.

This guide includes many terms related to infrared instrumentation, sampling, measurement techniques, basic nomenclature and concepts, data processing, and applications of infrared instrumentation. In addition, this guide includes some data processing terms, a few statistical data analysis terms, and the essential chemometric terms for typical data preprocessing and calibration.

Jason R. Dwyer of the University of Rhode Island discusses the application of nanopore sensors to the analysis of natural and synthetic oligosaccharides and polysaccharides.

Integrating peak position, height, and width information is important to properly interpret infrared spectra. But do you understand why peak heights and widths vary? We explain.

Articles in this column have addressed five main areas: theory, functional groups containing the C-H bond, those containing the C-O bond, those with the C=O bond, and those with organic nitrogen compounds. Here, we review the concepts.

We review one final organic nitrogen functional group, representing explosive compounds. This is the nitro group, which requires a different set of interpretation rules.

Here we conduct an evaluation of significant operational parameters of IR microscopy for accurately determining the size of microplastics, with the overarching goal of outlining performance parameters that will help in the standardization of microplastics analysis.

Measurements of the optical proper ties of a ceramic material, Z93, which is in current use on the International Space Station (ISS), reveal why this material is successful for thermal control in the ISS implementation, and also point to potential future material design improvements.

Spectroscopic ellipsometry, correlated with UV-vis-NIR spectroscopy, is used to determine the optical constants of thin films, such as in GexSb40-xSe60 chalcogenide glass.

Portable spectroscopic instruments have not had significant visibility within the scientific community compared with, for instance, the current generation of high-performance laboratory mass spectrometers.

In celebration of Spectroscopy’s 35th Anniversary, leading spectroscopists discuss important issues and challenges in analytical spectroscopy.

Here, we continue our examination of the infrared (IR) spectra of organic nitrogen compounds with imides, which are a common chemical intermediate. IR can be used not only to identify imides, but also to distinguish between straight chain and cyclic imides. We explain how.

The N-H stretching and bending peaks can be used to distinguish primary, secondary, and tertiary amides and to ascertain protein structure. Here’s how.

Amides are an important functional group found extensively in polymers and proteins. There are three different families of amides. Here, is explained how to distinguish them using infrared spectroscopy.

Analysis of FDA Form 483 observations and warning letters for infrared spectrometers reveals a range of data integrity problems and a lack of laboratory procedures for the technique. Is your laboratory in the same situation?

The amine salt functional group contains ionic bonding, and is extremely polar, giving rise to a number of intense and uniquely placed peaks that are easy to identify for primary, secondary, and ter tiary amines.

Nitriles are easy to spot because of the unusual intensity and position of the C≡N stretching peak.

Significant progress is being made to harness the power of spectroscopy technique for medical research. An ongoing challenge, and area of development, in this effort, is to “see” more and more detail about biological activity, even within individual cells. Ji-Xin Cheng, a professor of biomedical engineering at Boston University, is advancing such work, by developing techniques like midinfrared photothermal (MIP) imaging and Raman spectromicroscopy. Cheng is the 2019 winner of the Ellis R. Lippincott Award, which is awarded annually by the Optical Society, the Coblentz Society, and the Society for Applied Spectroscopy, to an individual who has made significant contributions to the field of vibrational spectroscopy. Here, Cheng speaks to us about those techniques.

Our annual review of products introduced at Pittcon or during the previous year