Bio-Rad Aurum™ Total RNA Fatty and Fibrous Tissue Kit - Manual (Page 34)

Problem Possible Cause Recommended Solution
Low RNA A
260
/A
280
Some of the white Leave some of the
ratio interphase and the aqueous phase solution
(continued) organic phase behind to avoid
(containing proteins) transferring the white
were transferred with interphase with the
the aqueous phase aqueous phase (see
during aspiration into step 7 in the protocol)
a new tube
Starting material is After the sample
high in fat, proteins, disruption step,
polysaccharides, or centrifuge the lysate at
extracellular material, 12,000 x g for 10 min
causing RNA eluate at 4°C to pellet any
to be impure debris present. Transfer
the supernatant into a
new 2.0 ml micro-
centrifuge tube, leaving
behind the pellet. Avoid
transferring the excess
fat that collects as a top
layer in lipid-rich
samples. Perform this
step before adding the
chloroform
Wash solutions and Make sure that the pipets
elution solution were that are being used for
contaminated with RNA preparation are not
proteins and other used for protein and DNA
contaminants applications
The solution used to A
260
/
280
may vary based
dilute the RNA for on the pH of the
spectrophotometric solution used to dilute
reading has a low pH RNA samples. To get
(less than pH 6.5) more accurate and
consistent A
260
/
280
values, dilute your RNA
samples with a solution
that has a pH within the
6.5–8.5 range
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