Metrohm NIRS Analyzer PRO - Manual (Page 57)

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6. If a printed copy is needed, click on “Print Report”.
A copy is automatically saved to the Vision Diagnostic
Database. Click on “Close Report” when finished.
NOTE: We advise removing the standards from the sample window when not in use. The intense
light beam can warm the standards considerably, which will change their photometric response.
Please place the standards on the window only for current testing, and remove them promptly when
finished.
13.2.2 Reference Standardization
Reference Standardization is a method to set the photometric scale of the instrument to a known,
repeatable absorbance level. Ideally, the instrument reference scale should be set so that 100%
reflectance is equivalent to zero (0) Absorbance. This facilitates transfer of models from one
instrument to another of the same optical sampling geometry.
In practice, it is challenging to set the scale exactly, due to issues of cleanliness, temperature, and
atmospheric influences. However, the scale can be set closely. Fortunately, NIR instruments normally
use mathematical and chemometric modeling methods that compensate for minor photometric scale
differences between instruments.
1. Click on “Analyzer PRO Setup/Diagnostic”, then “Create
Reference Standard”.
This test is required to set the photometric scale to a known
absorbance value.
2. Vision shows this selection box, marked
“Select ERC Correction File”.
The term “ERC” stands for “External
Reference Correction”, which is another
term for Reference Standardization.
Essentially, this is a method to
mathematically correct the instrument
reference to the equivalent of 100%
reflectance.
Select the RSSP file, then click “Open”.