Basics of FT-IR Spectroscopy
What is FTIR Spectroscopy?
Fourier transform infrared spectroscopy (FTIR) is a technique used to obtain infrared spectrum based on the amount of absorption or transmittance of IR in a sample. FTIR is frequently used in a wide range of structural analysis and non-destructive measurement applications.
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How Does FTIR Spectroscopy Work?
FTIR can obtain an infrared spectrum by irradiating a sample with infrared light and performing a Fourier transform of the signals collected across all wavenumbers obtained.
Step-by-step FTIR Principle:
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• IR source emits broad-spectrum light
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• Interferometer modulates light intensity
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• Sample absorbs specific wavelengths (unique to molecular structure)
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• Detector captures transmitted light
The Fourier Transform converts the complex interferogram collected by the detector into a readable spectrum. This process translates intensity of interference light and light path difference into absorbance vs. wavenumber, enabling the identification of specific molecular bonds.
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• Computer applies Fourier Transform to generate the spectrum
Applications of FTIR
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• Pharmaceuticals – raw material ID, formulation QA, pharmacopoeia testing
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• Polymers & Plastics – material verification
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• Environmental Testing – microplastics, air filter analysis
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• Life Science – protein structural analysis
FAQ
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How is the Fourier Transform used in FTIR?
- The Fourier Transform converts the complex interferogram collected by the detector into a readable spectrum. This process translates intensity of interference light and light path difference into absorbance vs. wavenumber, enabling the identification of specific molecular bonds.
