Bio-Rad PureZOL™ RNA Isolation Reagent - Manual (Page 17)

Problem Possible Cause Recommended Solution
RNA is Cells grown in either For cells grown in monolayer,
degraded monolayer or aspirate the growth medium
(continued) suspension were and then add PureZOL
washed prior to directly to the plate. No
homogenization with washing or trypsinization is
PureZOL necessary. For cells grown in
suspension, pellet the cells
and aspirate growth
medium, then add PureZOL
directly to the pellet
Starting tissue sample Make sure that starting
was not immediately material is immediately
frozen, or had gone processed following
through several dissection. Alternatively, the
freeze-thaw cycles starting material can be
before RNA immediately frozen after
purification was dissection. Once frozen, do
performed not subject starting material
to freeze-thaw cycles.
Cultured cells were Cells should be lysed directly
dispersed by trypsin in PureZOL RNA isolation
reagent. Do not wash cells
or trypsinize prior to lysing
Genomic DNA Some of the white Leave some of the aqueous
contamination interphase (after phase phase solution behind to
separation) was avoid transferring the white
transferred with the interphase with the aqueous
aqueous phase phase (see step 6 in the
protocol)
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