BUCHI NIRMaste - Manual (Page 18)

4 Description of function
18 NIRMaster Operation Manual, Version A
Factors that can influence the measurement:
Not enough sample material available •
Sample not homogenious or representative •
Humidity of sample material •
Temperature of sample material •
Sample cup inadeqate (e.g. cup material and thickness, blind spots, dirt etc.) •
NOTE
The samples should either be measured at a constant temperature or the temperature influences •
must be considered during calibration.
Coarse grained samples should be milled before carrying out the measurement. Recommended
•
number of scans: Qualitative calibration: 4−16; quantitative calibration: 16−32;
granules: 64.
4 .2 .2 Transflectance mode
Translucent and opaque liquids can be analyzed via transflectance mode. The light penetrates the
liquid, is diffusely reflected by the reference plate and passes the sample a second time. The trans-
flected rays contain the spectral information of the sample.
Factors that can influence the measurement:
Not enough sample material available •
Air bubbles in the measurement path and under the transflectance cover •
Sample not homogenious or representative •
Temperature of sample material •
Sample cup or transflectance cover inadequate (e.g. cup material and thickness, blind spots, dirt •
etc.)
Diffuse reflecting / reference plate
Small, defined gap for liquid samples
Sensor
NIR light
Sample cup / petri dish
NOTE
The samples should either be measured at a constant temperature or the temperature influences •
must be considered during calibration.
Recommended number of scans:
• Qualitative calibration: 4−16; quantitative calibration: 16−32
Most liquid sample materials can be constantly analyzed with the help of a flow-cell adapter. •