Bio-Rad Model 491 Prep Cell and Mini Prep Cell - Manual (Page 11)

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2.4 Gel Tube Assembly
The gel tube assembly holds both the gel and the cooling core. The elution chamber cap and the gasket
mounted on the graduated gel column make up the upper part of the elution chamber. Two gel tube
assemblies are provided with the Model 491 prep cell: 28 mm ID and 37 mm ID. See Section 4.4 for
selecting the appropriate gel tube size for specific applications.
Fig. 4. Gel tube assembly. Cooling core collar (1), upper reservoir attachment, i.e. threaded connector (2), graduated gel column (3),
elution chamber cap with thumb screws (4), elution buffer inlet port (5), cooling buffer port (6), gasket (7), and O-ring (8).
2.5 Elution Chamber Base
The elution chamber base with the support frit holds the elution frit and the dialysis membrane directly
be neath the gel. The dialysis membrane provided with the Model 491 prep cell has a molecular weight cut
off of 6,000 daltons. A continu ous flow of elution buffer is directed through the channels of the elution
chamber gasket to the perime ter of the elution frit. As bands mi grate off the gel, they are washed to the
center of the frit, up through the elution tube in the center of the cooling core, and out to the peristaltic
pump, UV de tector (optional), and fraction collector. (The tracking dye, bromophenol blue (M
r
691), does not
pass through the dialysis membrane. The flow of elution buffer through the elution frit overcomes the force of
elec trophore sis in the down ward direction.)
Fig. 5. Elution chamber base and tube assembly. Elution frit (1) and large O-ring (2).
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