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Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53726-2398
Phone: (608) 231-9200
Fax: (608) 231-9592
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Featured Technology - Spectroscopy

 

fpl Elemental analysis - Inductively-coupled Plasma Elemental Emission Spectroscopy

ICP-AES is a highly sensitive method for quantitative elemental analysis. It is frequently applied for determining the amounts of wood preservatives or leaching preservatives from wood and for studies of water purification using wood fiber filters.

Key points: 
  • Very sensitive
  • Most elements
  • Quantitative
  • No chemical state information

fpl Infrared Spectroscopy - Fourier-transform infrared spectroscopy

Infrared absorption spectra are characteristic of organic functional groups. This instrument is mainly applied for qualitative identification of materials or changes in materials. Spectra can be obtained from smooth surfaces by the use of at-tenuated total reflectance optics. Small areas can often be examined through the use of an infrared microscope accessory.

Key points: 
  • Chemical functional groups
  • Sometimes quantitative (relative)
  • Liquids, powder, surface
  • Interpretation sometimes difficult

fpl Nuclear Magnetic Resonance Spectroscopy (NMR)

NMR is often used to determine the way in which atoms of a compound are con-nected to each other. While mass spectra indicate which atoms are present in a compound, NMR elucidates how they are arranged. Natural materials often have similar composition but behave differently because of different linkages.

Key points: 
  • Chemical function
  • Chemical structure
  • Materials in solution


fpl X-Ray Photoelectron Spectroscopy

X-Ray photoelectron spectroscopy (XPS, ESCA) involves irration of specimens with monochromatic x-rays which promote the removal of a core or valence electron. The escaping electron has a kinetic energy that is determined by the energy of the photon and the binding energy of the electron to an atom. The kinetic energy of the emitted electrons is measured by an electron analyzer and the numbers of electrons corresponding to each element are counted.

Key points: 
  • XPS is an ultrahigh vacuum technique
  • XPS is surface sensitive
  • Electron binding energy is dependent upon the element and its chemical state
  • Survey spectra is used to determine which elements are present
  • High resolution spectra is used to determine chemical state information