136 1200 Series DAD and MWD User Manual
8Maintenance
Intensity Test
The intensity test measures the intensity of the deuterium and tungsten lamps
over the full wavelength range (190 – 950 nm). Four spectral ranges are used
to evaluate the intensity spectrum. The test is used to determine the
performance of the lamps and optics (see also “Cell Test (ChemStation
only)” on page 141). When the test 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 water in the flow cell. The
shape of the intensity spectrum is primarily dependent on the lamp, grating,
and diode array characteristics. Therefore, intensity spectra will differ slightly
between instruments. Figure 42 on page 137 shows a typical intensity test
spectrum.
Intensity Test Evaluation
The Agilent ChemStation evaluates four spectral ranges automatically, and
displays the limits for each range, the measured intensity counts, and passed
or failed for each spectral range (see Figure 42 on page 137).
Test Failed
Probable Causes
• Absorbing solvent or air bubble in flow cell.
• Dirty or contaminated flow cell.
• Dirty or contaminated optical components (achromat, windows).
• Old or non-Agilent lamp.
NOTE
The test is for the standard flow cells (10 mm and 6 mm pathlength) only. The nano-flow
cells (80 nl and 500 nl) cannot be run with this test due to its low volume.
NOTE
The evaluation report is only on the Agilent ChemStation available.
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