Metrohm NIRS XDS Process Analyzer – DirectLight/NonContact - Manual (Page 63)

▪▪▪▪▪▪▪ 61
A Wavelength Linearization is performed in the forward direction of grating scan, then again in the
return direction. The resulting information is adjusted by Vision into one corrected spectrum.
These peak positions are not meant to be
traceable, as the wavelength calibration of the
instrument is done on an external standard, at the
sample plane, as given by ASTM and USP.
The internal wavelength materials are used to
maintain the external wavelength registration by
use of software adjustment for any external effects
on the instrument.
Select Wavelength Linearization from the
Diagnostics menu. The instrument will scan the
reference, which is the fiber optic that runs from
the monochromator to the detector area inside the
instrument.
The results screen shown above is typical. Peak positions for the reference materials are located using
a peak-finding algorithm. These “found” peaks are compared to the nominals. Differences should be
no more than 0.4nm for any peak. Click “Yes” to send the linearization to the instrument.
This is done twice, one for each direction of the grating motion.