Eppendorf XplorerPlus - Manual (Page 61)

61
Eppendorf Xplorer® (plus) — Operating manual
8 General information on adjustment
8 General information on adjustment
The Xplorer pipette was calibrated before delivery and tested with double distilled water
according to ISO 8655.
Changing the adjustment of the Xplorer pipette is sometimes recommended for solutions with a
density, viscosity, surface tension and/or vapor pressure that vary greatly from that of water If the
density of an aqueous solution changes by approximately ±10%, e.g., due to the salt
concentration, the volume changes by approximately ±0.2%. This statement does not apply if
other relevant properties of the liquid also change.
If the pipette is used at extremely high altitudes, it must be calibrated to the ambient air pressure.
At 1 000 m above sea level, the volume error of a 100 μL pipette is about –0.3%.
Changing the adjustment can improve the dispensing accuracy (systematic error) when using
tips that have a very different geometry than standard tips.
You can cancel a modified adjustment using simple steps.
Changes to the adjustment do not affect the precision (random error) of the dispensing. The
precision (random error) can be improved by replacing worn parts. Furthermore, handling has a
strong influence on the precision (random error).
Before the adjustment is changed, the existing adjustment must be checked in the factory
settings using distilled water.
The actual volume can be checked by weighing:
The density of distilled water is Approx. 0.9982 mg/μL at 20°C and 0.9965 mg/μL at 27°C.
If the set volume corresponds to the actual volume, no correction is necessary.
If there is a difference between the actual volume and the set volume of distilled water, please
check the following:
• Is there any liquid dripping from the tip?
• Is the pipette tip fitted leak-proof?
• Is the tip cone undamaged?
• Are the piston and the cylinder leak-proof?
NOTICE!
Incorrect dispensing volume with special liquids and from temperature differences.
Solutions which differ greatly from water in terms of their physical data, or temperature
differences between the pipette, pipette tip and liquid, can result in incorrect dispensing volumes.
 Avoid temperature differences between pipette, pipette tip and liquid.
 Check the dispensing volume and make sure that you can affirm all the questions listed in the
general information.
Hint!
The random and systematic errors determined before delivery can be found in the enclosed
Eppendorf Certificate. If the factory settings are superseded by a different adjustment, the
Eppendorf Certificate is no longer valid. If you reset the adjustment to the factory settings, the
random and systematic errors determined before delivery and the enclosed Eppendorf
Certificate are once again valid.
Hint!
Adequate leak tightness is ensured when no drop is formed at the pipette tip after aspiration of
the nominal volume with distilled water and a waiting time of approx. 15 s. Hold the pipette
vertically, without touching the pipette tip. Prewet the pipette tip several times.
8
General information on adjustment