2 reference standardization, Reference standardization – Metrohm NIRS Analyzer PRO User Manual

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The “OpQual” tab gives

acceptance specifications,
along with actual results
and a “Yes/No” indicator to
test status.

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.

13.1.2

Reference Standardization

Reference Standardization is a method to set the photometric scale of the instrument to a known,
repeatable 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 quite difficult to set the scale exactly, due to issues of cleanliness, temperature, and
atmospheric influences. Fortunately, NIR instruments normally use mathematical and chemometric
modeling methods that compensate for minor photometric scale differences between instruments.

Click on “Analyzer PRO Setup/Diagnostic”, then “Create

Reference Standard”.

This test is required to set the photometric scale to a known
absorbance value.