Analytik Jena CyBio Well vario OL3381-25-300, Operating Manual

Page: 70 / 164

54 Release: 2017 CyBio
®
Well vario
Initial Start-Up & Routine Start-Up Procedure
6.3.3 Leak Test
Leak testing is required, in order to make sure that the pipettor head is free from points
of leakage. Subject to testing are the pistons, the pipette tips and the silicon mem-
brane.
Testing is performed through aspiration of a certain volume of dye solution into the pi-
petting tips and visually tracking the level of liquid over a time of two hours (96 wells)
or using a different procedure for 384 well pipetting heads, which is described further
below.
Test sequence

Make sure the system is in a horizontal position. Carefully place a spirit level onto
the transport rails for this purpose. Use setting screws for horizontal adjustment
as necessary.

Remove old tips.

Thoroughly inspect silicon membrane for cracks or sedimentation, using a suit-
able light source. Carefully clean the silicon membrane using a dust-free, slightly
moistened piece of cloth. Exert only moderate pressure, in order to prevent
unwanted shifting of the membrane. Use caution to prevent sedimentation
remaining in the membrane openings as you wipe the membrane clean. Allow
the membrane to dry.

Install tip magazine with new tips and clamp the tips.

Bring the reagent reservoir into position under the tips.

Raise the reagent reservoir to tips level — the pipette tips should submerge by at
least 2mm below the surface of the test solution.

Moisten the pipette tips on the inside by performing five rinse cycles.

Aspirate 50 % (of end volume) of dye solution.

Visually check the liquid level of all pipette tips over at time of two hours. Docu-
ment all tips with a non-conforming liquid level.

Visual testing may be hard to perform with 384 well/25 μ l pipette tips. In cases
like this, you should follow a procedure similar to
→
“Precision Test” : After half
an hour, completely dispense the nominal volume into a 384 well microplate with
flat transparent bottom containing prefilled buffer solution and measure extinc-
tion in the vertical photometer. The volume dispensed per pipetting tip should
not deviate from the mean value by more than 20 %.
NOTE
Keep the pipette tips submerged during leak testing, in order to prevent formation of
droplets at their ends, because droplets may falsify the result of testing.