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Symptom: Samples spread over the gel producing sample-specific bands between the lanes following the “iso-pH-lines”.
This could happen particularly if IEF-gels with slots are used.
Cause: Due to the slightly wet gel-surface and osmotic effects of the samples the sample volume is migrating first on the gel's surface before they enter the matrix. So they end up in a focused state but not only in the lanes.
This effect will be multiplicated if the gel will be cooled during sample application: in a warm and humide laboratory the gel’s surface will collect condensation water.
Remedy:
1. Start to cool the chamber not before the lid is closed. Use the “Bypass”-technique
to cool the kryostate’s water. See picture below.
2. Carefully dry the gel's surface using a cardboard.
Attention! The gel-matrix is very soft. When the cardboard sticks to the gel it may
be damaged.
3. Use filter papers (General Electric 80-1129-46) instead of frames or nets.
4. If available use special IEF-gels with slots. Only for special applications.
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