411829-L, Collection and Fractionation April 2012 Page A-2
A
4. Manual: The collection is started and stopped by the user. Fractionation only occurs on
volume.
• External detector: The system uses the signal from the external detector for collection only.
A.1.4 Possible Combinations
The possible combinations of collection and fractionation methods are listed in Table A-1.
Manual Collection
When using the Manual collection method, collection is started and stopped manually and
fractionation occurs on volume, which is when a test tube or bottle is full (based on the specified
max fraction volume for the vessel type). You can also at any time switch to a new collection vessel
manually by pressing New Fraction at the Status tab.
Collect All
The Collect All collection method fractionates using the same principles as the Manual method as
well as when a valley is detected in the light absorption curve, if the Valley Slope parameter is
enabled (in the System mode).
Threshold
The Threshold collection method fractionates using the same basic principles as the Collect All
method. When the collection is started and stopped depends on the signal(s) from the detector.
When a dual detector is used with the UV1+UV2 detection mode, collection is started when one of
the signals used for collection and fractionation reaches the specified Start Threshold level.
Fractionations occur when the other signal reaches the Start Threshold level and then when one of
the signals decreases below the Start Threshold level. When both signals decrease below the Start
Threshold level, the collection is stopped.
Slope
The Slope collection method fractionates using the same basic principles as the Collect All method.
When the collection is started depends on the calculated slope that is based on the signal from the
detector. The collection is stopped when the signal is below the absorption level detected when the
collection was started.
When a dual detector is used with the UV1+UV2 detection mode, collection is started when the
calculated slope of one of the signals used for collection and fractionation reaches the specified
Start Slope setting. Fractionations occur when the other signal’s calculated slope reaches the Start
Slope setting and then when one of the signals decreases below the absorption level detected when
the collection was started. When both signals decrease below the level detected when the collection
was started, the collection is stopped. The Slope collection method also enables the possibility to
fractionate when shoulders are detected in the light absorption curve.
Table A-1: Possible Combinations of Methods
Collection
Method
Fractionation Method
Manual Volume Valley Shoulder
Manual XX
Collect All XXX
Threshold XXX
Slope XXXX
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