2012 Product Catalogue

Specac Product Catalogue 2012 | Spectroscopist’s Hints and Tips
Spectroscopist’s Hints and Tips
The following hints and tips on Infrared Sampling may help you achieve better spectra with
greater ease. Don’t forget to contact your local Specac representative if you need any help
with your application. Contact details are listed at the back of this catalogue.
Reflection Measurements
Two ways of reducing the ATR penetration depth
into a strongly absorbing sample are choosing an
ATR crystal with a higher refractive index (see the
list of optical material properties at the back of
this catalogue), and selecting a larger angle of
incidence.
When analyzing powdered samples using ATR,
pre-grinding the sample will improve the
homogeneity of the sample particles, and yield
better spectra.
Aerosol spray samples can be conveniently
analyzed using the ATR technique. Spray the
contents onto a flat or trough top-plate, in a fume
cupboard, away from the spectrometer
compartment.
Lacquers and coatings can be analyzed for
specular reflectance in the following way. Wrap
aluminium foil (shiny side out) around the
reference mirror and apply the coating. Allow to
dry and record spectra of the resulting film.
When using diffuse reflectance the sample
heights are not alway uniform. Each time the
sample is changed it is desirable to reach the
optimum height and peak energy as quickly as
possible. A rolling micrometer on the Specac
Minidiff Plus accessory adjusts the height in
seconds, without using tools.
Level the surface of a sample for diffuse
reflectance measurement by gently tamping
down the surface, using a glass slide resting on
the surface under its own weight. Do not press
the surface hard, and risk compacting the
sample. The surface can be seen through the
glass slide.
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