Bio-Rad BioFrac™ Fraction Collector - Manual (Page 66)

5 | Stand-Alone Operation
58 | BioFrac Fraction Collector
 Windows Collection — enables you to specify periods of time or volumes
(windows) during which fractions are to be collected. For example, a
window can be defined to start after an initial void volume. The BioFrac
fraction collector lets you define up to 20 different time or volume windows.
The liquid delivered during a collection window is collected into tubes,
whereas the liquid delivered outside of a collection window is diverted to
waste.
 Peak Detection by Threshold with Time or Volume Windows — enables
you to combine the Peak Detection by Threshold and the Time or Volume
Windows methods discussed above. This method can be used only when
the fraction collector is connected to a UV monitor. You can program up to
20 different time or volume windows, each with its own threshold level.
This is a useful feature to compensate for baseline drift.
Note: False peaks above a threshold (such as electrical noise or air
bubbles) may be filtered using the bubble filter time function. See Appendix
A, Bubble Filter Time , on page 83.
 Delay Function — the purpose of the delay function is to synchronize the
fraction collection event marks and the signal from the UV monitor (output
on a chart recorder) with the actual delivery of liquid into collection tubes.
This features allows easy post-run analysis of a chromatogram. The delay
function is slightly different for each of the collection modes: All, Threshold,
Windows, and Threshold with Windows. As a consequence, the event
marks on the chart recorder will vary depending on the individual
application.
Regardless of the type of collection method programmed, the method will end once
the end tube number is reached. Always ensure that the start and end tube numbers
are set to allow completion of your collection method.