Analyzing Samples
Agilent Cary 630 FTIR Spectrometer User’s Guide 55
Collecting a background spectrum
To collect a background spectrum using the Diffuse Reflectance
accessory:
NOTE
Since the sample holder contains three sample positions, it may be convenient to
place KBr sample mixtures into Positions 2 to 4, and measure the background,
immediately followed by each sample.
1 Insert the sample holder into the Diffuse Reflectance accessory.
2 Collect a background spectrum using the diffuse gold mirror. For
software instructions for collecting a background, refer to the
MicroLab PC Software User’s Guide.
NOTE
On occasion, it may be necessary to use the KBr in pure form as the background
material. This is especially true if the KBr contains any moisture.
CAUTION
To ensure an accurate background spectrum is collected, perform a visual
inspection of the diffuse gold mirror surface looking for any haze, film or major
scratches present on the mirror from use or cleaning. If any of these are
observed, a new reference mirror may be needed.
Collecting a sample spectrum
To measure a solid material using the Diffuse Reflectance
accessory:
1 Sample preparation is key to achieving acceptable diffuse
reflectance spectra. Mix the sample with KBr at a 3 to 5%
concentration level. This is typically done with a mortar and
pestle to achieve a homogenous sample.
2 Transfer the samples to the appropriate holder position. Do not
contaminate other positions.
3 Completely fill the position and then use a spatula or flat sided
tool to create a flat surface and remove any overfill.
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