Bio-Rad Experion DNA Analysis Kits - Manual (Page 45)

Technical Support: 1-800-4BIORAD • 1-800-424-6723 • www.bio-rad.com 41
Error Probable Cause Recommended Action
No peaks detected in
some samples Samples were not prepared properly Review the sample preparation procedure detailed in
Chapter 3
DNA stain was photobleached Protect the DNA stain and gel-stain solution (GS) from light
Prepare new GS; use a new tube of DNA stain if necessary
Particulates are clogging the microchannels Use only high-quality, 0.2 µm-filtered water (such as
Experion DEPC-treated water, not autoclaved water)
Verify that the gel (G) and GS were properly filtered
If using samples that contain particulates, perform a quick
microcentrifuge spin of the prepared sample to pellet
particulates before loading
No peaks detected in any
samples Gel-stain solution (GS) is old or has been
photobleached Prepare fresh GS
Chip was not primed with the correct pressure
and time settings Check settings on the priming station and repeat the
analysis with a new chip
Particulates are clogging the microchannels Use only high-quality 0.2 µm-filtered water (such as
Experion DEPC-treated water, not autoclaved water)
Verify that the GS was filtered properly
If using samples that contain particulates, perform a quick
microcentrifuge spin of the prepared sample to pellet
particulates before loading
Lower and/or upper marker
is missing Samples do not contain sample buffer or were
not prepared properly (if both are missing) Review the sample preparation procedure in Chapter 3
Late migration If only the upper marker is missing, refer to the
troubleshooting tips for late migration (below)
Electropherogram peaks are
much smaller than expected
(peaks are <50% of what is
expected) Too much stain in the gel-stain solution (GS);
sample cannot destain completely, and the
background is high; too much stain can
contribute to high background and low sample
and ladder peaks Prepare new GS using a new tube of stain. Ensure stain is
thawed completely before preparation
Not enough sample was added Ensure pipets are calibrated
Use pipets that accurately deliver volumes of ≤10 µl
Too much salt in the sample; salt ions compete
with the sample ions during injection Analyze a dilution series of the sample in water on another
chip. If the peak heights and calculated DNA concentrations
of the diluted sample increase, the salt is too high in the
original sample. Determine the proper dilution to minimize
the salt effect
Gel-stain solution (GS) is old or has been
photobleached Prepare fresh GS
Reagents, specifically the DNA stain, were not
brought to room temperature prior to use; if
stain is not equilibrated to room temperature, it
will be more concentrated when it is added to
the gel, which may result in significantly lower
peaks and areas Repeat the analysis with a new chip, new tube of stain, and
properly equilibrated reagents
Gel-stain solution (GS) was mislabeled or
used improperly. DNA chips contain specific
wells for GS that carry the sample through
microchannels and supply dye for analysis Ensure chip was primed with GS
Ensure GS was used in all wells marked GS
Experion DNA 1K and DNA 12K Analysis Kits