Pipetting Guidelines & Precautions; Pre-Rinsing Recommended; Reverse Mode Pipetting - OHAUS ACROSS PRO AO-2 Manual Del Usuario

Pipetting Guidelines＆Precautions
Consistency in all aspects of pipetting will significantly contribute to
optimum reproducibility.
1. Consistent pickup/dispense rhythm while pipetting.
2. Consistent speed and smoothness when you press and release the
pushbutton.
3. Consistent pushbutton pressure at the first stop.
4. Consistent immersion depth.
5. Minimal angle (
6. Never invert or lay the pipette down if liquid is in the tip.

Pre-Rinsing Recommended

Some solutions (e.g. serum, protein-containing solutions, and organic
solvents) can leave a film on the inside tip wall, resulting in an error larger
than the tolerance specified. Since this film remains relatively constant in
successive pipetting with the same tip, excellent precision may be obtained
by refilling the tip and using the refilled volume as the sample. Successive
samples from this same tip will exhibit good reproducibility.

Reverse Mode Pipetting

Reverse mode pipetting is recommended for highly viscous, biological or
foaming liquids, or very small volumes of liquid.
1. Mount a disposable tip on the pipette shaft.
2. Press the pushbutton fully to the second stop.
3. Immerse the tip in liquid and return the plunger slowly to the full up
position. Wait a moment for the liquid column to reach equilibrium in the
tip.
4. Wipe any excess liquid from outside of the tip without
touching the orifice.
5. To dispense, rest the end of the tip against the vessel
wall and press the plunger to the first stop only. Hold at
the first stop for a few seconds-long enough for the liquid
column to reach equilibrium again.
6. Remove the tip from the receiving vessel without blowing
out the remaining liquid.
7. Return excess sample in the tip to the original sample
container, if desired. Discard the used tip.
6
20° from vertical)
＜