Infrared Spectrum Spectrogram Analysis

Infrared (IR) spectroscopy is created by analyzing the pattern in which a substance absorbs infrared light. These absorptions correspond to the vibrations of chemical bonds and atomic groups in molecules. In the analysis of biological structures, infrared spectroscopy is an extremely valuable tool as it can provide detailed information about the structure of biomolecules.

 

Basic Principle

When infrared light is irradiated onto a sample, the sample will absorb light of specific wavelengths, which correspond to the vibration frequencies of chemical bonds in molecules. The light that is not absorbed is recorded by the detector. Different chemical bonds and functional groups in molecules have different vibration modes (such as stretching, bending, etc.), and each vibration mode corresponds to a specific wavenumber (usually represented in cm^(-1)) in the infrared spectrum.

 

Spectrum Analysis

Infrared spectroscopy typically displays the relationship between transmittance or absorbance and wavenumber. Specific chemical bonds and functional groups in biomolecules (such as proteins, nucleic acids, lipids, and carbohydrates) will produce characteristic absorption peaks in the spectrum. For example, the peptide bonds (C=O) in proteins usually produce a strong absorption peak at about 1650 cm(-1), which is due to the stretching vibration of the carbonyl group.

 

Structural Identification

By analyzing the characteristic peaks in the infrared spectrum, specific functional groups and chemical bonds present in the sample can be identified. This can also help determine the secondary structure of biomolecules. For example, in proteins, α-helix, β-pleated sheets, and irregularly coiled structures exhibit different absorption patterns in the infrared spectrum.

 

Dynamic Changes

Infrared spectroscopy can also be used to study the dynamic changes of biomolecules, such as protein folding, aggregation, and other biochemical processes. By monitoring how specific absorption peaks change over time, researchers can understand the details of molecular interactions and structural changes.

 

Quantitative Analysis

Although infrared spectroscopy is mainly used for qualitative analysis, it can also be used for quantitative analysis. By comparing the absorption peaks of unknown samples with those of known concentration samples, the concentration of unknown samples can be determined.

 

Disease Research and Diagnosis

In medical and biological research, infrared spectroscopy is used to study the pathological state of cells and tissues. Different types of cells and tissues, or cells and tissues in healthy and diseased states, will display different characteristic absorption peaks on the infrared spectrum.

 

It should be noted that the analysis of infrared spectra requires experienced experts to correctly interpret the spectra, and it usually needs to be used in combination with other analysis methods (such as mass spectrometry, NMR, etc.) to obtain a more comprehensive understanding of biomolecules.