Bio-Rad PureZOL™ RNA Isolation Reagent - Manual (Page 18)

Problem Possible Cause Recommended Solution
Genomic DNA Phase separation not Make sure that centrifugation
contamination performed at the right step is performed at 4°C
(continued) temperature following the addition of
chloroform in order to
achieve complete separation
of the phases
Insufficient amount of Scale up the amount of
PureZOL used for PureZOL used according to
sample lysis and sample size. Sample volume
homogenization should not exceed 10% of
the PureZOL reagent used
for homogenization.
RNA Starting material is After the sample disruption
contamination high in fat, proteins, step, centrifuge the lysate at
with extracellular or polysaccharides 12,000 x g for 10 minutes at
material 4°C to pellet any debris.
Transfer the lysate into a
new RNase-free tube, leaving
behind the pellet. This
should be done before
adding the chloroform.
Section 7
Reference
Chomczynski P and Sacchi N, Single-step method of RNA isolation
by acid guanidinium thiocyanate-phenol-chloroform extraction, Anal
Biochem 162, 156–159 (1987)
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