An Overview of FTIR Spectroscopy And Its Applications

Fourier transform infrared (FTIR) is the most commonly used form of infrared spectroscopy. When Infrared (IR) radiation passes through the sample, these infrared spectroscopies act on the principle. During the entire process, it absorbs some of the radiation. 

Experts record the radiation that passes through the sample. The process begins to produce different spectra from molecules with different structures. They utilize the spectra to recognize and distinguish among the molecules.

Reasons Why FTIR is a Prefered Infrared Spectroscopy Method

  • Does not destroy the sample
  • Faster than conventional methods
  • More precise and sensitive 

For these reasons, it reveals the benefits of FTIR deriving from the interferometer use. Because it is the infrared source, it enables greater speed, and the Fourier transform. This method is a mathematical function breaking up waves and returns the wave frequency based on time. 

The Fourier transform will convert the interferogram into the infrared spectroscopy spectrum graph identified and used by people.

Uses of FTIR Spectroscopy 

  • Polymer Science
  • Organic Synthesis
  • Food Analysis
  • Petrochemical Engineering
  • Pharmaceutical Industry 

Some of the most dependable tools today are the Agilent FTIR spectroscopy instruments. The company also offers different Fourier transform infrared spectroscopy accessories and supplies. They have different applications to identify compounds and determine mixture components. 

How does FTIR function?

When the covalent bonds of a molecule absorb the radiation (certain wavelengths), it changes the bond’s vibrational energy. Because of this, the vibration bends or stretches depending on the atoms in the bond induced by IR radiation. Various functional groups and bonds absorb different frequencies; different molecules reveal varying transmittance patterns.   

They record the spectrum on a graph with a cm-1 wavenumber. The recorded data is on the X-axis, and the recorded transmittance is on the Y-axis. 

Reading the Spectrum of FTIR

In reading the spectrum of FTIR, it is essential to determine and understand the bonds and groups corresponding to which peaks. Research experts often use reference tables for different groups to help them.

Major FTIR Sampling Techniques

  • Specular Reflection 
  • Transmission 
  • Diffuse Reflectance
  • Attenuated Total Reflection 

Because these techniques have varying strengths and weaknesses, it actuates their specific sample uses.

Fourier transform infrared spectroscopy is used in research and industry conventionally. It benefits many researchers because it ensures an easy and reliable measurement technique, effective dynamic and quality control measurement, and utilization in civil and criminal analysis.

5 Major FTIR Spectroscopy Applications

1. Functional group identification and structure interpretation

The fingerprint and frequency regions divide them into groups from the entire region of Infrared. Here is the range of interpretations:

  • Frequency Region Range (4000-15000 cm-1)
  • Fingerprint Region Range (1500-400 cm-1)

In the frequency region group, the observation is that the peaks correspond to varying functional groups. They determine the functional group based on similar peaks. 

Each molecule atom connects by a bond, and every bond requires a different Infrared region. With this, there is an observation of characteristic peaks. This IR spectrum region is what they recognize as the molecule fingerprint region.   

2. Substance Identification

They utilize FTIR to help establish whether a given organic substance sample corresponds with another. The explanation is that they observe many absorption bonds in the organic molecules’ IR spectra. 

There is zero probability that any two compounds can produce similar spectra. If two compounds produce the same IR spectra, they come from identical sample substances. The 2 enantiomeric compounds of IR spectra are the same, which means the FTIR fails to distinguish between the enantiomers.        

3. Impurities Detection 

The process happens by comparing the standard compound with the test sample of the IR spectrum to determine. If they observe any additional Infrared spectrum peaks, the compound reveals the presence of impurities. The main function of the FTIR instrument is to detect impurities.   

4. Study the Chemical Reaction Progress 

Research experts determine the chemical reaction progress by occasionally examining the reaction mixture on a small portion withdrawn. During the observation of the product formation, they study the progress cautiously.

Below are the following matters they observe:

  • Characteristic absorption band disappearance rate (reactant group) 
  • Characteristic absorption band appearance rate (product group)

5. Analyzing Substance Quantity 

Determining the substance quantity can be in a pure compound or a mixture of more than 2 compounds. The analysis procedure chooses the characteristic peak identical to the drug substance. The standard peaks log at 10/It and then compared with the test sample.    

To determine the substance quantity, they call it the baseline technique. 

FTIR Sampling and Applications 

Fourier transform infrared is a precise and flexible instrument for research. As a single-purpose device, it is a configured instrument for specific sampling. 

Here are the common functions of the FTIR: 

  • Identifies and distinguishes the unknown
  • Provides quantitative information (contaminants or additives)  
  • Provides complex data when linked to other instruments
  • Provides kinetic information (IR absorptions growth or decay)

This type of spectroscopy is fundamentally a cost-effective answering machine.

The Use and Power of FTIR Spectrometer 

It is best to gain some dispersive IR spectrometer background information to understand the use and power of the FTIR. The dispersive IR spectrometer’s basic components include the following:

  • Detector
  • Radiation source
  • Monochromator

The resources of Infrared radiation come from heated electrically inert solids. The process promotes thermal radiation emission in the electromagnetic spectrum IR region. A monochromator disperses a broad Infrared radiation spectrum into single restricted IR frequencies.

About Dispersive Infrared Spectrometers   

In general, the design of the Infrared dispersive spectrometers has 2 equivalent beams. They appear on the same source that passes through a sample and references chamber. The beams function alternatively, focusing on the detector, which uses a sector mirror.

One of the beams travels through a sample, and the other passes through species of reference. This procedure is essential for transmitted photon wavefront information-analytical comparison.  

Biotechnology Today

Fourier transform infrared spectroscopy is mainly concerned with the molecules’ vibration. Every functional group presents a distinct energy of vibration used to characterize a molecule. FTIR can identify a molecule through all functional group combinations. 

As technology grows, so does biochemistry. FTIR is just one of the tools that emerged to help us uncover the world’s greatness.

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