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F. Helpful Hints
• Liquid tends to adhere to the walls of small tubing (such as tube
sets for 384-well plate), especially when dispensing smaller
volumes (9 uL or less). To minimize the amount of liquid retained
in the tubing, make sure that the Y-axis arm positions the tips
directly over the middle of the wells and the height gauge is
used to set the nozzle over the plate. See Y-axis arm adjustment
on page 18.
• When using a new tube set, prime the tubing for 5-10 minutes
with water before using the set for testing. This initial priming
helps to break in the new tube set and stretch out the tubes
where they contact the roller head.
• Prolonged use of a tube set, especially if it is used constantly
and not allows to “rest,” can cause results to vary over time.
Possible reasons include: accumulation of bubbles in the tubing
because the tubes were not fully purged; general wear over
time.
• Continuous use of a tube set may also cause droplets to form
outside the tips. You can reduce this problem by periodically
checking the tips and gently removing any droplets with a sterile
cloth. The greater the dispense volume or more frequent the
dispenses, the more often the tips should be checked.
• Tube sets containing liquid and left idle for a long time can
collect bubbles in the tubing. Purge the tube set, run air through
the tubes, then prime with liquid.
• Tube sets that are not used for an extended period of time
should be released from the roller head. Open the clamp lever
to the rest position or take the tubing cartridge off the roller head
completely.
• Persistent droplets that form outside one or more tips during
dispenses may be caused by tip fl ash (fl aw in the tip). This
problem can cause inaccurate results. The tube set should be
replaced.
• For optimal dispense precision (especially with 384 well plates),
set the nozzle height over the plate to 2.0 mm or less.
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