The Microspectrophotometer

1
The Microspectrophotometer

• The microspectrophotometer is a spectrophotometer
  coupled with a light microscope.
• The examiner studying a specimen under a
  microscope can simultaneously obtain the visible
  absorption spectrum or IR spectrum of the
  material being observed.
• This instrument is especially useful in the
  examination of trace evidence, paint, fiber, and
  ink evidence.

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The Microspectrophotometer cont

• Advantages
• Chemists can now examine small particles
• Both types of examinations can be done
  simultaneously
• Provides added information to trace evidence
• Allows the analysts to determine if two fibers of
  the same color are actually the same

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The Scanning Electron Microscope

• The scanning electron microscope (SEM) bombards a
  specimen with a beam of electrons
• Produce a highly magnified image from 100x to
  100,0000x.
• Its depth of focus is some 300 times better than
  optical systems at similar magnification.
• The specimen can be viewed on a closed TV circuit

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The SEM cont

• The bombardment of the specimens surface with
  electrons normally produces X-ray emissions that
  can be used to characterize elements present in
  the material under investigation.
• Good for determining if a suspect recently fired
  a gun by identifying microscopic gunshot residue

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