Bio-Rad PROTEAN® Plus Hinged Spacer Plates and Combs - Manual (Page 3)

Section 1
Introduction
The Model 385 and Model 395 Gradient Formers are primarily used to construct repro-
ducible linear and exponential polyacrylamide gradient gels. Both gradient formers can also
be used to construct sucrose density gradients for ultracentrifugation or elution gradients for
column chromatography. To obtain optimal chromatography elution gradients, tubing with an
inside diameter • 1/16" must be used.
The Model 385 Gradient Former has a 30-100 ml capacity, making it ideal for the con-
struction of one or two identical standard (16 x 20 x 0.15 cm) polyacrylamide gradient gels,
or up to 10 identical miniature (8 x 7 x 0.15 cm) gradient gels. The Model 395 Gradient
Former has a 100-700 ml capacity, making it ideal for the construction of up to 12 identical
standard (16 x 20 x 0.15 cm) gradient gels using a gel casting chamber.
The mixing and reservoir chambers of both gradient formers have identical dimensions.
The outlet from the mixing chamber leads through a peristaltic pump (not required for linear
gradients) to a single gel, to a Y for two gels, into a gel casting chamber for multiple gels. The
gradient may be cast from the top or bottom of the gel sandwich. When the gradient is formed
in a gel casting chamber, the gradient can be cast only from the bottom. Exponential pistons,
available as accessories for both gradient formers, are used to fix the volume in mixing cham-
ber to produce concave or convex exponential gradients.
Fig. 1.1. Model 385 and 395 Gradient Formers, major parts.
1
Exponential piston
Reservoir chamber
Luer taper coupling
Mixing chamber
Peristaltic
pump Valve stem
Stopcock
Tubing
Y-connector