PerkinElmer Spotlight 400 Series, User Manual

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60 . Spotlight 400 Series User’s Guide
Fibers
You can roll fibers to flatten them (see
Flattening Solids
on page 54), or they can be pressed
in a diamond anvil cell (see
Polymers
on page 56). The following is another approach.
Fibrous Solids
If a fibrous sample, such as paper, is too thick, tear it and examine the torn edges. The
edges contain single fibers and thin clumps of fibers.
Coatings on Substrates
If the sample is coated on a substrate, the method for collecting its spectrum depends on the
nature of the substrate:
•
If the substrate is reflective, you can analyze the sample in reflectance. If the sample is
only weakly reflective or scatters the signal strongly, use the diffuse reflectance
sampling mode.
• If the substrate is opaque, scrape off a sample of the coating; use the roller knife to
scrape a small piece on to a KBr or BaF
2
disk.
Liquids
Solutions of samples
Although liquids are seldom analyzed with the imaging system, sometimes the sample of
interest is in solution.
1. Transfer the solution on to a salt plate.
2. Allow the solvent to evaporate, leaving the sample on the plate.
Micropipettes
You can use a micropipette to apply liquid to the surface of a salt plate, or to the edge of the
junction between two salt plates. In the latter case, the liquid flows between the plates by
capillary action.