Bio-Rad PROTEAN® IEF Cell Accessories - Manual (Page 10)

2.2 Basic Operation
2.2.1. Programming Parameters
The PROTEAN IEF Cell programs control the following parameters of an isoelectric
focusing run.
a. Rehydration
IPG strips must be rehydrated prior to isoelectric focusing. The PROTEAN IEF Cell
provides the option of including a temperature controlled rehydration step in the
focusing program or programming a separate rehydration program.
The user can perform the rehydration step in one of 3 ways.
• Integral Rehydration—the rehydration step is an integral step of a method.
• Separate Rehydration—the rehydration step is programmed separately using
the rehydration mode.
• Other Rehydration—the rehydration step is performed outside the
PROTEAN IEF cell.
IPG strips are rehydrated with buffer that may or may not contain the sample. IPG
strips rehydrated with sample may be actively or passively rehydrated.
Active or Passive Rehydration
Active rehydration is only used when the sample is contained in the rehydration
buffer. Active rehydration applies 50V to the IPG strips during rehydration to
facilitate uptake of the sample into the IPG strip. Active rehydration requires the
use of an isoelectric focusing tray.
Passive rehydration can be done with or without sample present in the
rehydration buffer. The IPG strips are rehydrated without any voltage applied to
them. Passive rehydration can be performed in either the rehydration/equilibra-
tion tray or the isoelectric focusing tray.
Rehydration Time
Rehydration time is programmable within the range of 00:01–99:00 hours. The
recommended rehydration time (default value) is 12 hours.
Pause After Rehydration
A pause can be programmed after the rehydration step and prior to isoelectric focusing,
whether you are using the pre-set or user-defined programs. A pause is needed for
inserting electrode wicks, adding mineral oil, applying sample or transferring the
strips from the disposable rehydration/equilibration tray to the focusing tray. If a
pause is not inserted, then the program will proceed immediately to the first focusing
step.
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