Performing A Wavelength Validation And Wavelength Calibration - Thermo Scientific Vanquish VH-D10 Operating Manual

7 • Maintenance and Service
7.5 Performing a Wavelength Validation and
Wavelength Calibration
When
Preparations
Page 120
A holmium-oxide glass filter is used to validate the wavelength accuracy.
The filter can be moved into the light path between the lamp and the
flow cell for the wavelength validation. The detector determines the
absorption maxima of the filter and compares them to the nominal
holmium oxide values that are stored in the detector firmware.
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
A wavelength validation can also be performed with an external
standard, such as a pyrene solution. In this case, an accuracy of ± 1 nm
can be achieved.
A wavelength validation is recommended in the following situations:
• After moving the detector
• After the flow cell has been exchanged
• After a lamp has been replaced
Before you start the wavelength validation or wavelength calibration,
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.
• Allow the lamp to warm up and reach operating temperature. The
lamp should be running for at least 1 hour before you start the
wavelength validation or wavelength calibration. A lamp spectrum
changes significantly during the first few minutes after a lamp has
been turned on.
NIST Compliance (} page 185).
Diode Array Detectors (VH-D10)
Operating Manual