Raman and FTIR Spectromicroscopy

Raman and Fourier Transform Infrared (FTIR) are vibrational spectroscopies that detect changes in a chemical bond’s polarisability (ie. The electron cloud around bond) and dipole moment, respectively. Both techniques are complimentary, and many vibrational modes are both Raman and IR active. In some cases, when there is a center of inversion in the crystal symmetry of the material, some vibrational bands will be only Raman active or IR active (not both – rule of mutual exclusivity).

The Renishaw Invia Reflex Raman microscope (Renishaw, Gloucestershire, UK) located within the SSSC is its only kind in Canada, as it also equipped with an IlluminatIR II FTIR microscope accessory (Smith’s Detection, Danbury, CT). In addition, the Invia Reflex microscope supports multiple laser wavelengths, along with sophisticated software that allows automatic switching of lasers. This allows multiple excitation wavelength Raman and FTIR spectroscopies to be obtained on the same spot with relative ease for the general user!

Renishaw Invia Reflex Raman Microscope

The Renishaw Invia Reflex Raman Microscope (Renishaw, Gloucestershire, UK) is fitted with a IlluminatIR II FTIR microscope accessory (Smith’s Detection, Danbury, CT) for measurement of Raman and FTIR spectra without having to move the sample to different spectrometers. Raman and FTIR and complimentary vibrational spectroscopy methods that are based on different principles but when combined almost all vibrational modes can be measured.

Specifications

Laser Pathway
Light Path Filter Set Polarizers Grating (line/mm)
514 nm Ar+ Laser (Modulaser Model XXX) Edge Filters (100 cm-1) Yes - z(x,x)z' and z(x,y)z' 1200, 1800, 2400 (special request)
785 nm Laser Diode (Renishaw) Edge Filters (100 cm-1) Yes - z(x,x)z' and z(x,y)z' 1200
Light Microscope Leica DC2500M equipped with 5X (NA=0.12), 10X (NA=0.25), 20X (NA=0.40), 50X (NA=0.75), 100X (NA=0.85), 50X LWD (NA=0.40)
XYZ Motorized Stage MS20 Encoded Stage, Renishaw, UK) with 100 nm step sizes which allows for the capability of very high spatial resolution mapping. Coupled with the correct laser excitation and objective, and spatial resolution can be better than 0.5 μm!
FTIR IlluminatIR II FTIR accessory is equipped with a liquid nitrogen cooled MCT detector allows measurements in the 4000-650 cm-1 range with up to 4 cm-1 spectral resolution. The system uses a 15X (NA= 0.88) ARO objective (10-100 μm aperture) or a 36X diamond ATR objective (10-50 μm aperture).

Settings

Solids: generally μg quantities are all that are needed
Liquids: 50-100 μL (Measurements are conducted through transparent material).
Raman Mapping – Samples should be relatively flat (microtome biological sections) to ensure good optical focus while mapping.

Applications

  • Line maps, Depth profiling, Streamline™ Mapping provide chemical maps of samples
  • Biological Samples (Microtomed tissue samples, cells, bacteria, purified materials, etc.)
  • Agricultural products and by-products
  • Drug delivery
  • Functional group identification
  • Carbon material(s) characterization (carbon nanotubes, graphene, biochar, a-C thin films, nanodiamond, etc.)
  • Crystallinity, and phase distribution of minerals and catalysts
  • Stress/strain properties in semiconductor materials
  • Surface enhanced Raman spectroscopy (SERS)

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