Fourier Transform Infrared Spectroscopy

Fourier-Transform Infrared Spectroscopy (FTIR)

- Is an analytical technique used to identify organic, polymeric, and, in some cases, inorganic materials.
- It measures how a sample absorbs infrared (IR) light at different wavelengths, producing a spectrum that represents the molecular "fingerprint" of the sample.
- Is widely used because it is fast, non-destructive, and requires minimal sample preparation

Absorption of infrared light

What does FTIR measure to identify materials?

Non-destructive

This feature makes FTIR convenient for routine analysis, as it doesn't damage the sample.

Infrared light

What kind of light is used in FTIR spectroscopy to induce molecular vibrations?

Molecular vibrations

What occurs at the molecular level when specific IR wavelengths are absorbed by a sample in FTIR?

Interferometer

The device in FTIR that modulates infrared frequencies into a measurable signal.

Beer–Lambert Law

Which law explains the relationship between absorbance, concentration, and path length in FTIR spectroscopy?

Fourier transformation

This mathematical technique is used in FTIR to convert encoded optical signals into an interpretable spectrum.

Infrared Source
Interferometer
Sample Holder
Detector
Computer

Main Components/Parts of the Instrument

Infrared Source

Main Components/Parts of the Instrument
This component emits infrared radiation. The source typically operates in the mid-infrared range, where many molecular vibrations occu

Interferometer

Main Components/Parts of the Instrument
- Modulates the infrared light. typically a Michelson interferometer.
- It splits the light into two beams, which travel different paths and then recombine.
- This process creates an interference pattern that is recorded as the interferogram.

Sample Holder

Main Components/Parts of the Instrument
- Is where the sample is placed for analysis.
- The modulated IR beam then passes through the sample.
- As it interacts with the sample, specific wavelengths of light are absorbed depending on the molecular composition of the sample.

Detector

Main Components/Parts of the Instrument
Measures the intensity of the transmitted or reflected infrared light after it interacts with the sample. And converts the incoming infrared light into an electrical signal that can be analyzed.

Computer

Main Components/Parts of the Instrument
Processes the data collected by the detector. It performs a Fourier transform on the interference pattern to convert it into a spectrum

- Material/Drug Identification
- Detection of Impurities/ Contaminants
- Ensures Batch Consistency
- Monitoring Drug Stability

Applications of FTIR Spectroscopy in the Pharmaceutical Industry

Observation of potential contaminants in processed biomass using Fourier Transform infrared spectroscopy

Title Article

Solvent Contaminants
Acids and Alkalis
Ionic Liquids
Dessicants
Biological Contaminants
Biomass- Derived Contaminants

Sample/ Contaminant Types

Acetone, Ethanol, Methanol, THF, Doixane, Toluene, Glycerol, Chloroform, Pyridine

Sample/ Contaminant Types
Solvent Contaminants

H2SO4
HCI
H3PO4
Acetic Acid
NaOH

Sample/ Contaminant Types
Acids and Alkalis

BMIM-CI
BnMIM-Cl
ChCl- Urea
ChCl- PHA

Sample/ Contaminant Types
Ionic Liquids

CaCl2
MgSO4

Sample/ Contaminant Types
Desiccants

Bacteria
Fungi (Penicillium/Bacillus)

Sample/ Contaminant Types
Biological Compounds

Residual Lignin
Hemicellulose

Sample/ Contaminant Types
Biomass- Contaminants