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Bio-Rad PROTEAN® i12™ IEF System User Manual

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Chapter 2 Basic Operation

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PROTEAN i12 IEF System Instruction Manual

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Fig. 2.4. Placement of an IPG strip gel-side down into the i12 focusing tray.

IEF with Gel-Side Down
For IEF of IPG strips that were rehydrated in the presence of sample (in-gel sample loading):

1. Position the electrode assemblies in the focusing tray and press down on the green tabs to snap the

electrode assemblies into place (Figure 2.4, A; see Section 2.1.1, i12 Focusing Tray and Electrode
Assemblies).

2. (Recommended) Wet the rectangular (gel-side down) wicks with distilled or deionized water and blot off

excess water. Use two wicks per IPG strip: place a wick on top of each electrode (Figure 2.4, B).

3. Using forceps, place the rehydrated IPG strips gel-side down in the channels of the focusing tray (Figure

2.4, C). Position the positive (+) ends of the IPG strips against the positioning stops in each channel.

4. Place the focusing tray on the Peltier platform and connect the electrodes to the instrument (see Section

2.1.2, Connecting the Electrodes).

5. Overlay each IPG strip with mineral oil (see Table 2.1 for recommended volumes).
6. Place the IPG strip retainers on top of the IPG strips at both the positive and the negative ends (Figure

2.4, D). Without IPG strip retainers in place, gases formed during electrolysis may lift IPG strips off the
electrodes, interrupting electrical contact.

7. Select or program the protocol(s) and start the run (see Section 2.3, Starting the Run).

(Recommended) Place
wet electrode wicks in the
channels of the focusing tray.

Place the focusing tray onto the Peltier platform,
connect the electrodes, and then place 2 IPG strip
retainers on top of the IPG strips.

Place both electrode assemblies in the focusing tray. Press down
on the green tabs to snap the assemblies into place.

A

B

Place IPG strips gel-side down in the channels of the
focusing tray.

C

D

To avoid movement of the IPG strip retainers, which can damage the IPG strips, place them into
the focusing tray after the focusing tray has been secured on the Peltier platform.

IPG strip positioning stop