Hoefer HE99X - Manual (Page 18)

•
p10
Notes, buffers, and volumes
Running buffers for DNA in agarose gels
Recipes for the three most commonly used
running buffers for DNA electrophoresis are
listed below. The buffering capacity of both
TBE and TPE is usually sufficient so that buffer
circulation is unnecessary. Circulation may be
required during runs longer than 3 hours or
when using the TAE buffer.
1. 10X Tris-borate-EDTA (TBE) stock buffer a
(0.89 M Tris, 0.89 M boric acid, 20 mM EDTA,
pH ≈8.3, 1000 ml)
Tris base (FW 121.1)
0.89 M 108.0 g
Boric acid (FW 61.8) 0.89 M 55.0 g
EDTA solution 0.02 M 40.0 ml
(0.5 M, pH 8.0, solution 4)
Deionized H
2
O to 1000.0 ml
Stir. Do not adjust pH.
Before use dilute either to:
0.5X, to yield 45 mM Tris base, 45 mM boric acid,
and 1 mM EDTA. This dilution is often used because
current remains low, resulting in less heat.
— or—
1X, to yield 89 mM Tris base, 89 mM boric acid, and
2 mM EDTA.
Important! Do not adjust the
pH of these buffers once
they are prepared according
to the recipe!