Metrohm NIRS XDS MasterLab Analyzer - Manual (Page 85)

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to illustrate that the wavelength peaks of SRM-2035 remain constant, even when neutral density
filters are added to increase absorbance level, as with the top spectrum. The SRM-2035 peaks are
consistent even at higher absorbance levels.
The XDS master instrument is verified as meeting NIST SRM-2035 nominals during Instrument
Calibration, since these are the best known information for NIR transmission peak wavelengths.
Peaks for the additional ingredient are set to peak nominals determined by measurement on several
different types of research instrumentation.
In Wavelength Certification, the NIST-stated uncertainty of 1.0nm for wavelength position is applied.
Tighter tolerances are not appropriate, unless NIST revises the stated uncertainty of SRM-2035 at
some point in the future.
7.1.4 IPV Setup, Tablet Transmission (Instrument Performance Verification)
IPV Setup is provided as a method to record initial instrument response to calibrated photometric
tablet transmission standards. This is normally performed upon initial installation, when a lamp has
been changed, or when standards have been re-certified.
When the standards are scanned during IPV Setup, a file is generated, and is stored in the Vision
directory. This file has the same format as the standards file, but a “V” is placed into the fourth
character of the file name. This indicates that it is a “verification” file. For example, if the standard set
has the serial number TSS40001, the IPV Setup file is named TSSV0001.
With the IPV Setup file stored, the user can run Photometric Test to check the repeatability of
instrument performance. This is detailed later in this manual, in “Evaluation Diagnostics.” Photometric
Test compares the current performance of the instrument to the file stored during IPV Setup, and
reports differences. If the instrument differences exceed established tolerance limits, the test reports
that, so corrective action may be initiated.
It is important that IPV Setup, and later Photometric Test, both be run with the same options selected