Metrohm NIRS XDS Transmission OptiProbe Analyzer - Manual (Page 47)

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Insert the XC-1300 standard (labeled
WST3W011 in this instance) into the
calibration fixture as shown. Close the cover
to block stray light.
Temperature at the point of measurement
should be consistent. (20 degrees C is
typical.) Elevated temperatures will cause the
wavelength positions to migrate slightly.
Click “OK” to proceed.
Vision scans the WST3Wxxx standard.
At the end of the test this dialog box is
displayed. If hard copy is needed, click on
“Print”.
Click “OK” to exit Instrument Calibration.
The wavelength response for each defined peak is adjusted, to assure precise wavelength registration
between instruments. At the same time, bandwidth (bandpass) is measured, and is iteratively
adjusted to an optimum value for the peaks measured. This is performed to assure good agreement
from instrument to instrument, should multiple instruments be used for analysis of similar products.
This same XC-1300 standard will be used later during Wavelength Certification, to verify wavelength
positions set during Instrument Calibration.
It is important to note that two specific wavelength accuracy operations are performed during
Instrument Calibration:
1. Accuracy is measured against certain NIST-defined nominals, using the NIST uncertainty of +/-
1.0 nm.
2. Accuracy is also measured against tighter FOSS-defined wavelength parameters, which fall
inside of NIST-defined parameters. The FOSS-defined parameters are typically +/- 0.05 nm for the
XDS OptiProbe Transmission Analyzer.
These will be measured later in Wavelength Certification, as a test of how well the instrument is
maintaining the settings established in Instrument Calibration.
Instrument Calibration is quite reliable, and there are very few failure modes. If the test fails, verify
these things first: