Bio-Rad RC DC™ Protein Assay - Manual (Page 5)

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Note: Also see DC Protein Assay Instruction Manual for additional
troubleshooting recommendations.
Questions
1 May I use a wavelength other than
750 nm?
2 What should I do if the protein
pellet is still soft after centrifugation
for 3 to 5 minutes?
3 What can I do to minimize
interference from supernatant
carry-over?
Recommendations
Yes, absorbance can be measured at
650-750 nm.
Increase the centrifugation duration to
6-10 minutes. Protein pellet may take
longer to dissolve after the addition of
Reagent A´.
Option #1:
A second wash can be performed as
follows:
Standard Assay
After step #6, repeat step #4 with
500 µl of Reagent I, repeat step #5
with 160 µl of Reagent II, repeat
step #6 before going on to step #7.
Microfuge Tube Assay
After step #6, repeat step #4 with
125 µl of Reagent I, repeat step #5
with 40 µl of Reagent II, repeat step
#6 before going on to step #7.
Option #2:
At step #6: to maximize supernatant
removal, discard supernatant by
aspiration before going on to step #7.
Option #3:
After step #6, dry tubes under
vacuum to reduce residual
supernatant before going on to
step #7.
Section 6 Troubleshooting Guide
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