Bio-Rad Mini Trans-Blot® Cell - Manual (Page 17)

Mini-Trans-Blot Electrophoretic Transfer Cell 11
3.2 Notes on Electrophoretic Transfer Conditions
These variables will change total resistance and thus
the current readings:
• Alterations in buffer make-up, i.e., addition of SDS, or
changes in ion concentration due to addition of acid
or base to adjust the pH of the buffers
• Gel pH, ionic strength, and percentage of acrylamide,
especially if the gel has not been properly equilibrated
• Number of gels; current increases slightly as the
number of gels increases
• Volume of buffer; current increases when volume
increases
• Platinum mass; current increases when mass
increases
• Transfer temperature; current increases when
temperature increases
• Time in transfer at which reading was taken;
current normally increases as the buffering capacity
diminishes with progress of the run
Pre-equilibration of gels (15–20 min)
All electrophoresis gels should be pre-equilibrated in
transfer buffer prior to electrophoretic transfer.
Pre-equilibration will facilitate the removal of contaminating
electrophoresis buffer salts and neutralization salts (salts
resulting from the denaturation of nucleic acids prior to
transfer). If the salts are not removed, they will increase the
conductivity of the transfer buffer and the amount of heat
generated during the transfer. Also, low percentage gels
will shrink in methanol buffers. Equilibration allows the gel
to adjust to its final size prior to electrophoretic transfer.
Current limits
The PowerPac
™ Basic power supply is capable of a
75 W output. Unless a current limit is set, uncontrolled
conductivity changes may result in full power being
delivered to the Mini Trans-Blot
® cell.