Agilent Technologies G1314B, User Manual

Page: 106 / 208

106 Agilent 1260 Infinity VWD User Manual
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.
In the Agilent Instant Pilot G4208A, the photocurrent readings are
available via
More > Diagnosis > VWD > LampIntensity Test , see Figure 35 on
page 107.
Probable Cause Suggested Action
Cell contaminated Flush flow cell
Cell windows are contaminated Clean/replace cell windows
Mechanical problem Check cell position