Bio-Rad Model 111 Mini IEF Cell - Manual (Page 13)

7. Position a photopolymerization light (such as Bio-Rad’s catalog number 170-4220 or 170-
4242. See Section 9.2) over the tray. Any fluorescent desk lamp is a suitable alternative.
8. Irradiate the solution for 45 minutes.
9. To lift the gel from the casting tray:
a. Lift one corner with a flat spatula inserted between the gel and the casting tray (see
Figure 3.2).
b. When air appears under the gel, gently lift the plate free from the casting tray.
10. Flip the plate, glass side down, onto the casting tray and further irradiate for 15 minutes to
eliminate unpolymerized monomer on the gel surface.
Fig. 3.2. Lifting the gel from the casting tray.
3.6 Sample Preparation
Protein samples for isoelectric focusing must be free of precipitates. Substantially salt-free
samples in typical biochemical buffers are usually tolerated, though better results can be obtained
with solutions in deionized water, 2% ampholytes, or 1% glycine. Suitable protein solutions may
be prepared by dialysis, or gel filtration with Bio Spin® 6 chromatography columns (catalog
number 732-6000 (10) or 732-6002 (25)) or with Bio-Gel® P-6DG desalting gel (catalog number
150-0738).
Many samples will require the use of urea, ethylene glycol, non-ionic detergents (i.e. Triton®
X-100 detergent, NP-40, Lubrol® WX detergent, or octylglucopyranoside), or zwitterionic
detergents (CHAPS, CHAPSO). Even in the presence of detergents, some samples may resist
solubility due to salt requirements. Only if high salt is an absolute requirement should it be
present in a sample, and even then, substantial distortions and anomalies can be expected.
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