Bio-Rad Criterion™ XT Tris-Acetate Precast Gels - Manual (Page 18)

Section 7
Troubleshooting
Improper storage of Criterion XT gels can produce numerous artifacts. Criterion XT Bis-Tris gels should be
stored flat at ambient temperature. Criterion XT Tris-acetate gels should be stored flat at 4°C. Avoid freezing. If
you suspect your gels have been stored improperly, DO NOT USE THEM.
Problem Possible Cause Solution
Samples do not migrate into gel Tape at the bottom of the cassette Remove tape
not removed
Insufficient buffer in integral buffer chamber Fill integral buffer chamber with 60 ml
running buffer
Insufficient lower electrode buffer Fill both halves of the lower buffer tank with
400 ml running buffer when running two gels
Electrical disconnection Check electrodes and connections
Bands “smile” across gel, band pattern Excess heating of gel Check buffer composition
curves upward at both sides of the gel
Completely fill both halves of the lower buffer
tank with 400 ml running buffer when running
two gels
Do not exceed recommended running
conditions
Skewed or distorted bands, lateral Excess salt in samples Remove salts from sample by dialysis or
band spreading desalting column prior to sample
preparation
Insufficient sample buffer Check buffer composition and dilution
or wrong formulation instructions
15
4110130B.qxd 3/25/2003 2:19 PM Page 15