Infrared Spectroscopy
Infrared Spectroscopy - Related Videos
08:11
Infrared Spectroscopy
0 Views •
2023
Source: Vy M. Dong and Zhiwei Chen, Department of Chemistry, University of California, Irvine, CA This experiment will demonstrate the use of infrared (IR) spectroscopy (also known as vibrational spectroscopy) to elucidate the identity of an unknown compound by identifying the functional group(s) present. IR spectra will be obtained on an IR spectrometer using the attenuated total reflection (ATR) sampling technique with a neat sample of the unknown.
01:09
Infrared (IR) Spectroscopy: Overview
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2024
When electromagnetic radiation passes through a material, atoms or molecules transition from a lower to a higher energy state by absorbing radiation corresponding to the energy difference between the two states. The absorption of infrared (IR) radiation causes transitions between vibrational energy levels in a molecule. Therefore, IR spectroscopy is a useful analytical tool for determining the molecular structure of molecules. Different compounds display unique properties due to their...
03:04
A Fourier Transform Infrared Spectroscopy Technique to Study Peptide Self-Assembly
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2025
This video demonstrates the self-assembly of amyloid peptides into a beta sheet-rich supramolecular structure using Fourier transform infrared spectroscopy. An infrared beam is passed through a crystal with a high refractive index, and energy absorption across the interface of the crystal and the sample is recorded. The secondary structures of the sample proteins are identified by analyzing their characteristic absorption peaks at specific regions of the infrared spectrum, which aids in...
12:40
Exploring Cognitive Functions in Babies, Children & Adults with Near Infrared Spectroscopy
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Cited by 32 •
2009
Here we describe a data collection and data analysis method for functional Near Infrared Spectroscopy (fNIRS), a novel non-invasive brain imaging system used in cognitive neuroscience, particularly in studying child brain development. This method provides a universal standard of data acquisition and analysis vital to data interpretation and scientific discovery.
05:41
Functional Near-Infrared Spectroscopy for Recording Brain Activity During Social Interactions
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2025
Source: Reindl, V., et al. Conducting Hyperscanning Experiments with Functional Near-Infrared Spectroscopy. J. Vis. Exp. (2019) This video demonstrates the use of functional near-infrared spectroscopy (fNIRS) to measure brain activity during social interactions. Participants engage in a coordinated task that increases activity in the prefrontal cortex, a region critical for social behavior, while the system detects changes in light absorption due to blood oxygenation. By analyzing the synchrony...
FAQs
Stretching and bending vibrations create the molecular signals detected in Infrared Spectroscopy. A bond can absorb only selected infrared frequencies, and those absorptions appear as peaks in the resulting spectrum. The positions and pattern of peaks therefore connect the measured signal to particular chemical bonds, helping characterize the molecular content of a biological sample.
Functional groups serve as useful interpretive markers because they are recurring arrangements of atoms within molecules. Their characteristic absorption patterns help distinguish contributions from proteins, lipids, carbohydrates, and nucleic acids. Examining these patterns together, rather than relying on one peak alone, gives a broader chemical picture of the specimen being studied.
Complex biological samples contain many molecular classes whose bonds absorb different infrared frequencies. The resulting spectral pattern combines these signals and can reveal information about the chemical composition of cells, tissues, or biomolecular material. This makes the technique useful when researchers need molecular information from an intact biological specimen rather than from a single purified substance.
Infrared Spectroscopy can be applied to proteins, lipids, carbohydrates, nucleic acids, cells, and tissues. These targets allow investigators to study both individual biological molecules and more complex specimens. The same bond-based information can therefore support biomolecular characterization as well as broader analysis of cellular or tissue composition.
Researchers can examine changes in spectral patterns to follow biochemical changes in a biological sample. Because different molecular bonds contribute characteristic absorptions, altered patterns can provide evidence that the sample composition has changed. This supports studies of biological processes or sample variation while potentially preserving the specimen for further analysis.
In disease-related tissue studies, spectral patterns can provide information about molecular differences within biological tissues. The technique also supports quality assessment by characterizing the chemical features of biological samples. Since analysis does not necessarily destroy the specimen, it can be valuable when researchers need molecular information while retaining the sample for additional work.