Bio-Rad BioFrac™ Fraction Collector User Manual
Page 80
5
| Stand-Alone Operation
72
| BioFrac Fraction Collector
At the start of the run an event mark is recorded. Initially the liquid is diverted to
waste because the monitor signal is below threshold. When the UV signal rises
above the specified threshold of 10%, an event mark is recorded and the volume
corresponding to the delay time (or the delay volume) is collected in tube 1. At the
end of this time, there is a tube advance and the peak is collected in 1-minute
fractions. As the falling edge of the peak passes through the threshold, an event
mark is recorded, but there is no tube advance until the volume corresponding to
the delay time is collected. All subsequent peaks follow this same pattern, with a
tube containing the delay volume separating each peak.
Note:
When the delay time is set to zero, an empty tube separates the peaks.
Fig. 29.
Peak Collection by Threshold using a delay of 0.25 minutes.
When the non-peak (below threshold) liquid is diverted to tubes, the delay volume
(at the rising edge) of the peak is collected as part of the non-peak fraction. To
clearly distinguish between the two types of fractions in this situation, we suggest
programming a much larger non-peak fraction size.