In this blog, we will learn the secrets of the infrared spectrum and how this powerful technique allows us to analyze and understand ”the invisible world” on a molecular scale.
What is FTIR?
Fourier Transform Infrared Spectroscopy (FTIR) is an analytical technique widely used in different scientific and technological fields, such as chemistry, biology and materials science. It is based on the interaction of infrared radiation with the molecules of a sample, which provides information about its molecular structure and chemical composition. FTIR is a powerful tool for materials analysis and is widely used in research, quality control, and product development.
The main components of an FTIR system are:
- Infrared radiation source: An infrared radiation source is used, such as a laser or a halogen lamp, which emits radiation in the infrared range of the electromagnetic spectrum.
- Interferometer: The interferometer is the heart of the FTIR system. It consists of an optical device that divides the infrared radiation beam into two paths: a reference path and the other that passes through the sample. The two paths are then combined again, producing an interference pattern that contains information about the sample.
- Sample: The sample is the material to be analyzed. It can be a liquid, a solid or a gas. The sample is placed in a suitable cell that allows the beam of infrared radiation to pass through it.
- Detector: After the beam of infrared radiation passes through the sample and is combined in the interferometer, it is directed towards a detector. The detector converts the radiation into electrical signals that can be measured and recorded.
- Computer and software: The computer is used to control the FTIR system and acquire data from the detector. In addition, specialized software is used to analyze the data and perform signal processing.
These are the basic components of an FTIR system. However, it is important to note that there may be other additional items and accessories, such as automated sampling systems, special sample cell accessories (for example, attenuated total reflection cells), etc., depending on the specific application and the user needs.
When an FTIR spectrum is obtained, it is graphically represented as a graph showing the intensity of infrared radiation absorbed by the sample as a function of wavelength or wavenumber. The horizontal axis shows the different wavelengths or wave numbers, while the vertical axis shows the intensity of absorption. Each substance has its own spectral “signature”, which is represented by peaks or bands in the FTIR spectrum. These peaks or bands are associated with the molecular vibrations of the chemical bonds present in the sample. Interpreting FTIR spectra involves identifying and analyzing these peaks or bands. Here are some general guidelines for doing so:
- Wavelength or wavenumber range: Note in which wavelength or wavenumber range the peaks or bands lie. This can provide information about the type of molecular vibrations present.
- Number and location of peaks: See how many peaks there are and where they are located on the spectrum. Each peak or band can represent a specific molecular vibration. For example, a strong, sharp peak in the range of 1700-1750 cm-1 generally indicates the presence of a carbon-oxygen bond in a ketone.
- Peak Intensity: The height or intensity of the peaks can provide information about the relative amount of the substance present. More intense peaks indicate a higher concentration of that substance.
- Band Patterns: In addition to individual peaks, the broader band patterns should also be observed. Some substances may display characteristic bands or patterns of multiple spikes that are distinctive to certain chemical structures.
- Comparison with spectral libraries: To aid in interpretation, reference spectral libraries containing spectra of known substances can be used. By comparing the peaks and patterns of the unknown spectrum with those of the library, it is possible to identify the presence of specific compounds.
Interpretation of FTIR spectra requires knowledge and experience in chemistry and infrared spectroscopy. As you become more familiar with different compounds and their spectral characteristics, you will be able to make more accurate interpretations and gain detailed information about the chemical composition of a sample.
What is FTIR used for?
This technique is based on the principle that different molecules absorb infrared light at different wavelengths, allowing detailed information about the chemical structure and composition of a sample to be obtained.
Here are some important FTIR applications:
- Identification analysis: FTIR is a valuable tool for identifying chemical components in an unknown sample. By comparing the spectra obtained from the sample with a database of known spectra, it is possible to identify compounds present in the sample.
- Quality control: In industry, FTIR is used for quality control of chemicals, pharmaceuticals, polymers, materials, and other products. It allows to detect impurities and guarantee that the products meet the required specifications.
- Analysis of materials: The FTIR is applied in the study of solid, liquid and gaseous materials. It can be used to characterize polymers, fibers, coatings, paints, ceramics, and other materials.
- Life science research: In biology and biochemistry, FTIR is used to analyze biomolecules, such as proteins and nucleic acids, helping to understand their structure and function.
- Environmental studies: FTIR is used to monitor environmental contamination and analyze atmospheric gases, aerosols, and water. Pharmaceutical studies: FTIR is used in drug development and quality control to identify active ingredients and excipients, as well as to assess stability of the medicines.
ATRIA has used this technique in numerous projects. Here are some examples:
Recent advances and future prospects
There are several recent advances in the field of FTIR (Fourier Transform Infrared Spectroscopy) and exciting future prospects. Here are some examples:
- FTIR Microspectroscopy: Advances have been made in the FTIR microspectroscopy technique, which allows measurements to be made at the microscopic level or even at the level of a single cell. This has led to significant advances in the characterization of materials and tissues, as well as in the detection and analysis of biological samples.
- High-resolution imaging: The combination of FTIR with high-resolution imaging techniques has enabled the generation of detailed chemical images of complex samples. This is especially useful in areas such as biomedical research and materials science, where accurate and spatially resolved characterization is required.
- Resolution and Sensitivity Improvements: Continuous efforts have been made to improve the resolution and sensitivity of the FTIR. This includes advances in optics, detector technology, and interferometer design, allowing for more precise measurements and detection of smaller amounts of sample.
Looking ahead, we are likely to see further progress in the following areas:
- Development of hybrid techniques: The combination of FTIR with other analytical techniques, such as Raman microscopy and mass spectrometry, will allow a more complete analysis and a greater understanding of complex samples.
- Miniaturization and portability improvements: Smaller, more portable, and more affordable FTIR systems are likely to be developed, opening up new applications in environmental, food safety, and real-time monitoring.
- Applications in Emerging Fields: FTIR is expected to have an increasing role in emerging fields such as nanotechnology, food science, environmental research, and personalized medicine.
These are just a few examples of recent advances and future prospects for FTIR. The technology continues to evolve and it is expected that new applications will be discovered and developed as the understanding of the fundamentals of infrared spectroscopy progresses.
Advantages of FTIR
FTIR offers several advantages that make it a very useful and popular analytical technique. One of the main advantages of FTIR is its ability to provide structural and compositional information about a sample without the need to destroy or significantly modify it. Furthermore, FTIR is a non-destructive, fast and highly sensitive method. It allows the identification of unknown compounds, the quantification of components in complex mixtures, and the characterization of materials in different physical states, such as solids, liquids, and gases. It is also a versatile technique, as it can be used in different modes of analysis, such as reflection, transmission, and Fourier transform. In conclusion, FTIR is an essential tool for researchers and scientists who want to obtain detailed information about the chemical and structural properties of the samples they are studying. Its versatility and applications in a wide range of fields make FTIR a highly valued and reliable analysis technique. FTIR, an essential technique in the world of science and research.