Guide to Applications of IR Spectroscopy
Why use FT-IR spectroscopy? Here are 10 simple answers.
You'll find that almost every industry or institute in the world is using Fourier-transform infrared spectroscopy (FT-IR) in their research, development, manufacturing, quality control, failure analysis, or forensics. Pharmaceuticals, plastics, soil preservation, semiconductors, environmental studies, art and conservation - the list could go on for miles.
But why is that? We give you ten reasons why FT-IR finds widespread application in everyday life.
- Easy to use
FT-IR spectroscopy is very easy to learn and can be applied by almost everybody. - Universally applicable
FT-IR spectroscopy is applicable to all materials: solid, liquid, or gaseous. - Cost effective
The acquisition cost is low compared to other lab equipment (e.g. GC, LC, XRD). - Reliable and reproducible
FT-IR instrumentation is internally calibrated for max. reliability and productivity. - Sustainable
FT-IR analysis is non-destructive, produces no waste and uses no consumeables. - Safe and non-toxic
FT-IR foregoes potentially toxic substances or harmful radiation. - Time effective
Typical analysis time is about one minute including data evaluation and reporting.
- Globally available
FT-IR instruments only require a lab-environment and electrical power.
- Low space demand
The footprint of modern FT-IR instrumentation can be as small as a laptop. - Valuable for reverse engineering
FT-IR yields info about the chemical composition of (competitor's) samples/prodcuts.
FT-IR is very efficient and saves time.
FT-IR does not need toxic chemicals.
FT-IR works with all sample types.
Chemical identification by FT-IR spectroscopy
Identification of unknown samples is one of the most typical applications of FT-IR spectroscopy - especially in damage analysis, competition analysis and forensics.
Based on comprehensive spectral reference libraries and modern search algorithms unknown substances and even complex materials (mixtures) are identified without any prior knowledge in less than one minute.
Thus, FT-IR spectroscopy offers chemical analysis without consumables and in the shortest possible time. This is particularly powerful in microscopy, where tiny samples can be rapidly characterized chemically.
Material verification by FT-IR spectroscopy
The verification of materials and samples is, besides identification, one of the main tasks of FT-IR spectroscopy in industry and research. This can involve an chemical identity and batch conformity check of incoming raw materials but also the quality control of a manufactured product.
Typically, the use of FT-IR spectroscopy in incoming goods is one of the first analytical tools to be applied. On one hand the simplicity of using the FTIR method eases an implementation at any location, and on the other hand its analytical result helps to prevent production downtime and product quality issues.
Quantification of components by FT-IR
FT-IR can also be used to quantify the constituents of multi-component samples. In solid and liquid samples quantification within single-digit percentages are usually feasible. If lower concentrations are of interest, special sampling methods (e.g. extraction) may be required. For gases much lower detection limits are reached.
Generally, the IR data is calibrated based on reference methods. Here univariate methods like peak integration are used as well as multivariate chemometric algorithms such as Partial Least Squares. The great potential of IR lies in its capability to determine multiple parameters from just a single measurement.
Micro chemical analysis by FT-IR spectroscopy
When sample dimensions become too small for a macroscopic analysis FT-IR spectroscopy can also be applied in microscopy. The instruments used are called FT-IR microscopes, and are capable to perform a chemical analysis with a spatial resolution in the order of just a few micrometers.
In principle, all measurement methods of macroscopic FT-IR spectroscopy are also available here: transmission, reflection, and attenuated total reflection (ATR).
However, the use of ATR in microscopy is particularly powerful. Here, smallest samples can be examined non-destructively. A particularly popular example is the use in failure analysis to investigate tiny contaminations.
Chemical imaging by FT-IR spectroscopy
IR microscopic imaging allows to generate high-resolution chemical maps of the object under investigation. Basically, this technique creates a digital image in which each pixel contains an IR-spectrum from which information of the chemical characteristics of the sample can be derived.
Each individual pixel of the image can now be colored, e.g. depending on the identified components. This allows us to learn about the composition of inhomogeneous materials, to perform particle analysis (microplastics, technical cleanliness, pharmaceuticals), to detect defects in products, or to clarify the sequence of multilayer samples (coatings, paints, laminates, etc.).
