Metrohm NIRS XDS Process Analyzer – DirectLight/NonContact - Manual (Page 83)

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At the end of the test this dialog box is displayed.
Click “OK” to exit Instrument Calibration.
Select the next channel, if used. From the menu
bar, click on Acquire, then Select Channel. Use the
spinner to select the correct channel, then click on
“OK”.
This must be performed for each channel. Always
verify the channel before proceeding with the test.
Information about the Reflectance wavelength standard:
The reflectance wavelength standard used is directly traceable to NIST SRM-1920a, through direct
comparison on the Metrohm Master Reflectance Instrument, and in chemical formulation. In addition
to the prescribed formulation, one additional ingredient is added, in a small amount, to provide
peaks beyond those normally found in SRM-1920a. This material has very sharp bands, which are
found to be stable and repeatable.
Spectra of each are as described:
The darker spectrum, which has no discernible peaks beyond about 2150nm, is SRM-1920a.
The Metrohm WSR Wavelength Standard is the lighter spectrum, and has clear peaks visible at above
2200nm. These additional peaks are used to set the wavelength scale of the instrument to aid in
instrument matching. This is one important step in calibration transfer.
The Metrohm WSR Wavelength Standard exhibits slightly different absorbance and baseline levels,
due to the reflectivity of the added ingredient. The peaks, however, are in the same wavelength
positions, and are similar in shape to SRM-1920a.