BRAND PLT unit Mode D'emploi page 49

b c
a
Testing single-channel pipettes
What do the vertical progress bars in the display mean?
A mark is added to the progress bar. This indicates the threshold value. This
corresponds to approx. ¼ of the volume tolerance according to ISO 8655-2.
a) The progress bar is completely filled in to the bottom: The pipette is leak-
tight.
b) The progress bar is filled in from the top only down to the threshold value
region: We recommend that a gravimetric test be performed.
c) The progress bar is filled in to a point well above the threshold value: The
pipette leaks. A gravimetric test should be performed, and if necessary
the unit should be sent for repair.
What to do if there are leaks?
If a dynamic test indicates the presence of leaks, one can attempt to localize
the source with further testing:
1. A static test should be performed next.
The pipette button is not activated, and the piston is not moved. If the
pipette is now leak-tight, this suggests there are scratches on the piston.
2. The dynamic test should be performed without a tip.
Adapter 2 must be used in this case. If the pipette is now leak-proof, it is
possible that an unsuitable tip was used.
What do the letters after some volumes mean?
The additional letters after some volumes during volume selection mean:
y = Yellow (instrument with yellow tips)
c = Clear tips
n = nano-cap tip
soft = During the testing of 5 ml and 10 ml pipettes, the piston might no
longer move all the way back to top during the dynamic test, but
might remain stuck in the instrument due to vacuum and friction. In
this case, select the "5 ml soft or 10 ml soft" test mode.
Note on duration of tests
In the first test after switching the instrument on, a relatively large volume
must be pumped out, after which the instrument is given time to stabilize
(relaxation). Regularly switching between large and small pipette types leads
to longer test durations because the measurement pressure must be reset
each time.
The measurement time for pipettes up to 1000 μl is generally 5 s, while it can
be 20 s for 10 ml instruments.
49