Thermo Scientific Thermo Scientific Vanquish VC-D40, Руководство по эксплуатации

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7 • Maintenance and Service
Variable Wavelength Detectors (VC-D40, VF-D40)
Operating Manual Page 119
7.7 Performing a Wavelength Validation and
Calibration
A holmium-oxide glass filter is used to validate the wavelength accuracy.
The filter can be moved into the light path in front of the entrance slit
for the wavelength validation. The detector determines the wavelengths
of several absorption peaks in the resulting spectrum and compares
them to the nominal holmium oxide values that are stored in the
detector firmware.
A validation can be performed for all lamp configurations (both lamps
turned on, only UV lamp turned on, and, but least favorable, only VIS
lamp turned on (if available)).
The accuracy is verified for the wavelengths that are stated in the
declaration of conformity for the holmium-oxide glass filter. For
information about the declaration, see
NIST Compliance ( } page 163) .
A wavelength validation can also be performed with an external
standard, such as a caffeine solution. In this case, an accuracy of ± 1 nm
can be achieved.
When
A wavelength validation is recommended in the following situations:
• After the flow cell has been exchanged
• After a lamp has been replaced
Preparations
Before you start the wavelength validation, observe the following notes:
• Allow the flow cell to warm up for 5 minutes.
• Ensure that the baseline is sufficiently stable. The baseline may
become unstable, for example, if the solvent composition has been
modified, or if air bubbles are present in the light path.
• Verify that the solvent flowing through the flow cell is not strongly
absorbing in the wavelength range of the holmium-oxide glass filter
that is to be verified.
This problem occurs, for example, if the flow cell is filled with a
mixture of 96% hexane and 4% ethyl acetate. Thermo Fisher
Scientific recommends using degassed LC/MS-grade water.