Bio-Rad PROTEAN II XL Cell - Manual (Page 10)

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2.4 Upper Buffer Chamber
The completed gel sandwich attaches to the central cooling core so that the outer plate of the sandwich forms
the side of the upper buffer chamber. The inner plate is clamped against a rubber gasket on the central cooling
core to provide a greaseless, leak-free seal for the upper buffer. Each sandwich forms one side of the cathode
chamber. Tube gel adaptors also snap onto the central cooling core to form the upper buffer chamber walls
(one adaptor per side). If only one gel is to be run, an upper buffer dam is attached to the core to form the
complete upper buffer chamber. The upper buffer chamber will hold approximately 350 ml of buffer when full.
2.5 Lower Buffer Chamber
The lower buffer chamber of the PROTEAN II xi cell encloses the unit and provides stability during electrophoresis.
The molded unit requires a minimum buffer volume of only 1.1 liters for 20 cm plates, while providing excellent
heat exchange through the central cooling core.
2.6 Lid
Combined with the lower buffer chamber, the lid acts to fully enclose the PROTEAN II xi cell during electrophoresis,
thus providing electrical insulation. The lid cannot be removed without disconnecting the electrical circuit. It
can be placed on the lower chamber in only one alignment, so that the anode and cathode connections cannot
be accidentally reversed. The lid also holds the coiled electrical leads when not in use.
2.7 Tube Gel Adaptor
The tube gel adaptor clamps onto the central cooling core in one easy motion and provides a leak-proof seal
for the upper buffer chamber at voltages up to 1,000 V (especially useful for 2-D applications). The molded
construction produces a lightweight, yet durable adaptor unit, which has a gel tube locator at the bottom to
hold the tubes in a vertical orientation. Each adaptor can hold up to 8 tubes (from 1.0 mm ID to 6 mm ID); 16
tube gels can be run at once using two tube adaptors.
Note: The upper buffer dam may not be used opposite a tube gel adaptor.
2.8 Alignment Card
The alignment card greatly simplifies sandwich assembly by keeping the spacers upright during sandwich
alignment. A sandwich is assembled by placing two spacers on top of the large outer plate. The alignment
card is placed between the two spacers, and the shorter inner plate is then placed on top. Following attachment
of the clamps, the sandwich assembly is transferred to the alignment slot of the casting stand for final
adjustments.