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8
Test Functions
Cell Test
Cell Test
The cell test compares the intensity of the deuterium lamp measured by
the sample and reference diodes (unfiltered and not logarithmized) when
the grating is in the zero- order position. The resulting intensity ratio
(sample:reference) is a measure of the amount of light absorbed by the
flow cell.
The test can be used to check for dirty or contaminated flow cell
windows. When the test is started, the gain is set to - 1. To eliminate
effects due to absorbing solvents, the test should be done with water in
the flow cell.
Limits: No real limit. The reason is that it depends on the
position/alignment of the reference side (beam splitter – reference slit –
reference diode). Therefore the reference side value can be higher/smaller
than the sample side value.
With a clean cell the counts for sample and reference (photocurrent) are
in the same range. If the sample side shows much lower values than the
reference side the flow cell might have a problem.
Pre- requisite:
Flush the flow cell with a flow of 1 mL/min for at least 10 minutes.
Probable Cause
Cell contaminated
Cell windows are contaminated
Mechanical problem
In the Agilent Instant Pilot G4208A, the photocurrent readings are
available via More > Diagnosis > VWD > LampIntensity Test, see
page 107.
106
Suggested Action
Flush flow cell
Clean/replace cell windows
Check cell position
Agilent 1260 Infinity VWD User Manual
Figure 35
on
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