Fourier Transform Infrared Spectroscopy
(FTIR)

Bruker Vertex 80 Fourier Transform Infrared Spectrometer

The Bruker Vertex 80 Fourier Transform Infrared spectrometer is a high-end FT-IR spectrometer that provides an optical resolution of ˂0.06 cm-1 while allowing a full spectral range coverage form THz to UV. The FT-IR spectrometer can be mainly used to identify certain functional groups present in a molecule. It can also be used to confirm the identity of an authentic compound using a fingerprint analysis. The fingerprint analysis also could be used to detect the presence of specific impurities via diagnostic peak analysis. The instrument can operate in transmission, attenuated total reflectance (ATR) and diffuse reflectance modes while FT-IR microscope and a Raman spectrophotometer module attached to the instrument vastly expand its analytical capabilities. 

Principle

In FTIR spectroscopy, the sample is exposed to IR radiation. Some of the radiation is absorbed by the sample and some of the radiation is passing through the sample (transmitted). The instrument then detects these signals that are produced by the various methods (i.e. transmission, ATR, diffuse reflectance) to generate interferograms. FTIR spectrum is derived from the decoding of these interferograms into a recognizable spectral pattern. The unique spectral pattern produces by the sample leads to the molecular identification via the recognition of specific IR fingerprints.

Strengths

• Capable of identifying organic functional groups and often specific organic compounds
• Can operate under ambient conditions
• Complimentary to Raman spectroscopy
• Typically, non-destructive
• Inbuilt IR-microscope
• IR Quantification

Limitations

• Analysis of mixtures can be difficult unless a clean library match is present for the given mixture due to peak overlapping.
• Unable to analyse gaseous samples with the instrument.

Applications

• Research and development: Continuous and Step Scan technology for amplitude/phase modulation spectroscopy, rapid, interleaved and Step Scan technology for experiments with high temporal resolution (Step Scan / Rapid Scan / Interleaved TRS), Characterization of periodically ordered microscopic materials, known as metamaterials

• Pharmaceuticals: Differentiation of polymorphs of active pharmaceutical ingredients in the far infrared region, Qualitative analysis of active pharmaceutical ingredients and excipients

• Polymer chemistry: Identification of functional groups of polymer samples. Qualitative analysis of polymer starting materials and finished products and contamination analysis

• Material sciences: Characterization of optical and highly reflective materials (windows, mirrors) and the characterization of emittance behaviour of materials

Technical Specifications

• Signals detected : Infrared absorption
• Data obtained : Information regarding molecular functional groups
• Imaging : Available upon request
• Lateral resolution : 1 μm
• Spectral Range : Mid-IR, NIR, Far-IR/THz, Visible/UV 10 cm-1 to 50,000 cm-1 (200 nm)
• Spectral Resolution : Better than 0.2 cm-1 (apodized), optional better than 0.06 cm-1
• Detectors internal : Up to two 24 bit dual-channel ADC DigiTectTM
• Detectors external : Four, multiplexed up to 16
• Sources : Internal air cooled MIR, optional Tungsten NIR and external water cooled MIR, Tungsten, Hg-Arc and air cooled   Deuterium
• Internal Validation Unit and Aperture Wheel: Standard
• Rapid Scan : >110 spectra/sec at 16 cm-1 spectral resolution
• Slow Scan & Step Scan :10 Hz (0.00063 cm/sec), Phase modulation and internal demodulation, Temporal resolution 6 µsec/2.5 nsec