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Fourier Transform Infrared Spectroscopy and Microscopy

Fourier Transform Infrared (FTIR) spectrometry is a valuable instrument for understanding atmospheric chemistry, biological processes, and bioenergy production.

Two Bruker Fourier Transform Infrared (FTIR) spectrometers with IFS66/S systems capable of visible, near- and mid-infrared capabilities, and a LUMOS FTIR microscope are available to researchers through the EMSL User Program. The IFS/66s spectrometer includes a first-generation Bruker microscope with manual and motor drive capabilities for sample mapping that  includes a variety of sampling accessories that enable infrared spectra of various species. The modular design of the FTIR spectrometer enables rapid changing of the detector and beam splitter combinations, so researchers can readily change from visible to the near- or mid-infrared. The LUMOS is a fully automated stand-alone FTIR microscope with an eight times objective and can be used in transmission, reflection, and attenuated total reflectance (ATR) mode. All components of the LUMOS are motorized and electronically coded. The motorized ATR-crystal allows the system to switch from transmission or reflection to ATR mode without interaction of the operator and measure fully automated sample and background spectra, even in ATR mode.

 The FTIR can:

  • examine thin films and surface coatings on soils and sediments;
  • identify plastic particles in complex mixtures;
  • analyze defects and contaminants;
  • examine protein adsorption on mineral surfaces and water thin film on sediments and solids of environmental relevance;
  • identify unknowns in complex mixtures and the chemical composition of complex samples;
  • improve understanding of the reactivity of liquid and semi-solid secondary organic carbon with chloride and nitrate in atmospheric aerosols;
  • measure the interaction between organic acids and salt particulates; and
  • determine the primary functional groups of lignin and cellulosic material relevant to biofuel generation.

The Bruker ALPHA II spectrometer is also available for research use. The greatest advantage of the ALPHA II is its compact design—with a footprint the size of a laptop—and ability to offer spectral qualities comparable to large frame spectrometers. The small footprints allow it to be operated in limited spaces, such as glove boxes.

square beige and gray IFS 66S instrument at the Environmental Molecular Sciences Laboratory
The FTIR spectrometer supports the Terrestrial-Atmospheric Processes, Biogeochemical Transformations, and Cell Signaling and Communications Integrated Research Platforms.

Research application

  • The FTIR spectrometer supports the Terrestrial-Atmospheric Processes Integrated Research Platform by providing sample mapping and infrared spectra observations that can help understand key biogeochemical fluxes between critical zone, aquatic, atmospheric, and deep subsurface boundaries.
  • By assisting researchers in answering questions that are fundamental to our understanding of chemical, physical, hydrologic, microbial, and atmospheric interactions, the FTIR spectrometer supports the Biogeochemical Transformations Integrated Research Platform in its mission to cross scientific boundaries and investigate how the structure of nutrients, contaminants, aerosols, and other chemical compounds move and change in the environment.
  • The Cell Signaling and Communication Integrated Research Platform is supported by the FTIR spectrometer’s capabilities for sample mapping that allow for structural and functional analysis of isolated and individualized cells.

Available instruments

  • Bruker IFS/66s spectrometer integrated with FTIR microscope with an approximate resolution of 60 μm, sample cooling, and heating attachments
  • Bruker LUMOS FTIR microscope with integrated spectrometer and automatic measurements
  • Bruker ALPHA II spectrometer

Tips for success

  • For both microscope-based imaging and FTIR spectroscopy, sample thickness should be as thin as possible. Thick samples result in poor z-direction focus.
  • For most samples, the preferred measurement is transmission and attenuated internal total reflection as reflection mode measurements require a more stringent sample preparation procedure.
  • The preferred measurement mode for liquid samples is attenuated internal total reflection.

Contacts