EDC Impressum & DSE

Development & Consulting
Dr. Hanspeter Schickle
Wolfgang Gstrein

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Samples spreading over the gel

September 21, 2020

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.
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.


Remedy #1: Do not cool during the lid is open!