Wavelength Verification And Recalibration - Agilent Technologies 1220 Infinity II LC User Manual

9
Test Functions and Calibration
Diode Array Detector (DAD)

Wavelength Verification and Recalibration

The detector uses the alpha (656.1 nm) and beta (486 nm) emission lines of
the deuterium lamp for wavelength calibration. The sharp emission lines
enable more accurate calibration than is possible with holmium oxide. When
verification is started, the 1-nm slit is moved into the light path automatically,
and the gain is set to zero. To eliminate effects due to absorbing solvents, the
test should be done with bubble free degassed HPLC water in the flow cell.
If a deviation is found and displayed, it can be recalibrated by pressing Adjust.
The deviations are tracked in the Calibration History (diagnosis buffer in the
detector).
Figure 59 Wavelength Verification and Recalibration
Wavelength calibration should be done
• after maintenance of the flow cell,
• lamp exchange, or
• after a major repair, like processor board or optical unit exchange, see also
"Replacing the Module's Firmware" on page 325.
After calibration, the holmium oxide test (see Figure 55 on page 181) provides
verification of wavelength accuracy at three additional wavelengths.
1220 Infinity II LC System User Manual 187