BrandTech Scientific PLT unit Pipette Leak Testing Unit - Manual (Page 44)

Test preparation
Before the test, one must decide whether a dynamic or static test is to be
performed.
With the dynamic test, in addition to the detection of static leaks, one can
also determine whether a defective piston (contamination, scratches) has
caused a leak.
During the measurement time, the pipette button must be pressed down
completely and evenly 2-3 times. The associated piston movement allows
errors to be recognized.
The button stroke is accomplished relatively slowly with 5 ml and 10 ml
pipettes.
In the dynamic testing of pipettes, the piston should be in the upper position
at the beginning, and should be brought back to that position at the end.
In the static test, by contrast, the pipette button is not pressed during the
test procedure, i.e. the piston doesn't move. In power pipettes, one can posi-
tion the piston in the uppermost location or at the 1st stop.
A leak that occurs during the piston stroke can thus not be determined at this
point.
We recommend that the dynamic test be performed.
Dynamic or static test?
The test can take place with or without the pipette tip.
We recommend that the test be performed with a mounted, unused tip so
that the entire pipette system is tested.
When a leak has been identified, the test can be repeated without a tip to
determine whether the leak arises from the tip cone/tip coupling region.
The adapter must be changed (see page 46) to be able to perform the test
without the tip.
The pipette should be held firmly during the test.
Test with or without pipette tip?
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