Fourier Transform Infrared Spectroscopy analysis, or FTIR analysis, is a type of absorption spectroscopy and one of the most widely-used and reliable material quality control testing procedures used today.
If you’re considering FTIR analysis for your own material analysis or quality assurance applications, this is everything you should know about the process.
What is FTIR Analysis?
FTIR analysis is the use of Fourier-transform Infrared Spectroscopy for the observation and identification of various organic and inorganic materials in solid, liquid or gaseous forms. The term “Fourier-transform” refers to the fact that a mathematical process called a Fourier transform is required to convert the data collected via the analysis into useful identifying information about the sample itself.
Compared to other forms of Infrared Spectroscopy, such as the use of a dispersive spectrometer, FTIR analysis conveys three distinct advantages:
- Information from the infrared wavelengths is collected simultaneously
- Information is collected more clearly and completely
- Results are more accurate
These advantages, along with the speed and ease of the procedure, mean it’s often used as the first step in the materials testing process.
How Does FTIR Analysis Work?
Absorption spectroscopy techniques work by directing beams containing different wavelengths of light (such as X-ray, ultraviolet, or infrared) onto a sample and then measuring how much of that light the sample absorbs at each wavelength.
Bonds between different elements absorb light at different frequencies and in unique combinations. By measuring the extent to which a sample absorbs different wavelengths of light at different frequencies, it’s possible to understand that sample’s molecular composition and structure with an extremely high level of accuracy.
Conventionally, absorption spectroscopy is completed via the “dispersive spectroscopy” technique, wherein a single, monochromatic (containing a single wavelength of light radiation) beam of light is shined through a sample at a time, and each individual wavelength is measured separately.
FTIR analysis differs from this technique because it shines a broadband (containing a full spectrum of the wavelengths to be measured) through a device called a Michelson interferometer on its way to the sample.
A Michelson interferometer is a configuration of rotating mirrors. Each mirror blocks different types of light wavelengths as it interrupts the beam of light in different combinations of wavelengths. A motor rotates these mirrors very quickly, rapidly altering the frequencies (types) and combinations of wavelengths that contact the sample and producing a great deal of raw data on how much light the substance is absorbing at each mirror position. This data is called an “interferogram.”
Finally, a computer uses the Fourier transform algorithm to convert data on the substance’s absorption of light at each mirror position into the substance’s absorption of each wavelength of light.
This creates a map of the light absorption as it passes through the sample, in the form of a graph where light absorbance by the sample is the vertical axis and frequency (wavelength) applied is on the horizontal axis. By checking this graph against reference libraries, analysts can positively identify the composition of the sample.
What is FTIR Analysis Used For?
FTIR analysis can reveal the composition of solids, liquids, and gasses in minute detail very quickly, making it one of the most commonly applied testing procedures for a wide variety of applications. Some of the most common include:
Quality control & contaminant analysis
FTIR analysis’ ability to identify all of the extant substances within a sample all at once makes it a very valuable tool for quality control. An FTIR analysis can find and identify many surface contaminants on manufactured products such as electronics, plastics, metals, or medications.
FTIR analysis is particularly helpful for quality control because it not only identifies the existence of contaminants but can also immediately identify the specific contaminant at the same time. This helps manufacturers in a wide variety of industries track down where their product gets compromised and solve the problem.
For example, a medical device company recently discovered unknown fibers on their plastic packaging trays, which could compromise the functionality of their devices.
Using FTIR analysis, they identified the fibers as cellulose-based cardboard, then backtracked through their production process to find when the trays may have come into contact with cardboard.
They quickly found that cardboard dividers were used to separate the trays on the production line. Replacing these cardboard dividers solved the fiber problem.
FTIR analysis is very frequently used to determine why a product failed to perform to expectations.
For example, one of Innovatech’s clients produced air pumps that tested 100% functional in production, but when shipped to New Zealand, 80% of them failed due to stuck valves.
We found a white material on all the valves that stuck. Using FTIR analysis, we identified this material as diethyldithiocarbamate and hydrocarbon wax. The wax was from the surface of the product’s o-rings, while the dimethyldithiocarbamate was a bi-product of a fungicide used to protect the o-rings.
With this information, we could deduce that pumps shipped to New Zealand failed because their shipping containers were exposed to high heat, which caused the fungicide used in the product’s o-ring to bloom and expand onto the surface of the o-ring, jamming the valve. Removing the fungicide from subsequent o-rings solved the problem.
When Should I Use FTIR Analysis?
FTIR analysis is a highly useful way to:
- Identify unknown materials in solid, liquid, or gaseous form
- Understand the total composition of a complex compound, including additives
- Identify and quantify surface contaminants present on a material
- Understand the chemical composition of a potential contaminant
- Test the quality, durability, or vulnerability of a wide range of products and substances
- Solve virtually any organic material mystery at a molecular level
How Can I Get FTIR Analysis?
FTIR analysis is one of the most common and in-demand services Innovatech provides and we have been offering it for over 30 years. Our analytical scientists have years of combined experience using FTIR analysis to test all manner of products and compounds.
If you’d like us to test and analyze your product using FTIR analysis, get in touch right away.