Section 16- Troubleshooting
This warning occurs when a possible problem with the column is detected. The software compares the long path and
short path absorbances and issues a warning to the user if the short path is not 20% of the long path absorbance, within a
tolerance. The most common explanation is that the column is not forming properly due to the pedestal being
“unconditioned”.
When a pedestal becomes unconditioned, sample droplets applied to the bottom pedestal will 'flatten-out' and cover the
entire pedestal surface rather than 'bead up'. Buffers containing detergents and various other reagents may cause the
pedestal surfaces to become unconditioned. We have noted that routine use of the Bradford reagent may result in
difficulty forming columns with 1 ul samples.
Reconditioning
Use the NanoDrop Pedestal Reconditioning Compound (PR-1) as a rapid means of reconditioning the pedestals when the
surface properties have been compromised and liquid columns break during measurement.
1.
Open the vial containing PR-1 and use the applicator provided in the kit to remove a pin-head sized amount of the
compound. Note: Additional applicators may be purchased from VWR,
2.
Apply a very thin, even layer of PR-1 to the surface of the upper and lower pedestals.
3.
Wait 30 seconds for the PR-1 to dry.
4.
Fold a clean, dry laboratory wipe into quarters and remove the PR-1 by aggressively rubbing the surface of the upper
and lower pedestals until all compound residue is removed. Note: The black appearance of the removed residue is
normal.
The reconditioning process is complete once the laboratory wipe shows no more black residue. To check the
effectiveness of the reconditioning, load a 1 ul aliquot of dH
2
0 onto the lower measurement pedestals and visually verify
that the water “beads” up. Additional information about the PR-1 kit may be found at www.nanodrop.com.
As an alternative to using the PR-1 Kit, the pedestals may be reconditioned as follows:
1. Fold a clean dry lab wipe over several times to increase its thickness.
2. Press the lab wipe firmly down on the lower pedestal and "buff/rub" very aggressively at least 50 times - the lab wipe
will rip during this procedure and will have to be refolded several times throughout the procedure. The upper pedestal
may also be buffed but care should be taken not to put too much force on the upper arm.
If the warning persists and the user visually confirms that the liquid column is forming, contact NanoDrop Technologies or
your local distributor.
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