Sartorius eLINE User Manual page 36

pipettes having regard to the accuracy requirements of
the application, frequency of use, number of operators
using the pipette, nature of the liquid dispensed and the
acceptable maximum permissible errors established by
the user. (ISO 8655-1.)
Performance test should take place in a draught-free
room at 15–30°C, constant to ±0.5°C and relative
humidity above 50%. The pipette, tips and the test
water should have stood in the test room sufficient
time (at least 2 hours) to reach equilibrium with the
room conditions. Use distilled or de-ionised water
(grade 3). Use an analytical balance with a readability
of 0.01 mgs. (ISO 8655-6.)
Weighing:
1. Adjust the desired test volume V s .
2. Carefully fit the tip onto the tip cone.
3. Fill the tip with test water and expel to waste five
times to reach a humidity equilibrium in the dead
air volume.
4. Replace the tip. Pre-wet the tip by filling it once
with the test water and expel to waste.
5. Aspirate the test water, immersing the tip only
2–3 mm below the surface of the water. Keep the
pipettor vertical.
6. Withdraw the pipette vertically and touch the tip
against the side wall of the test water container.
7. Pipette the water into the weighing vessel,
touching the tip against the inside wall of the
vessel just above the liquid surface at an angle of
30° to 45°. Withdraw the pipette by drawing the
tip 8–10 mm along the inner wall of the weighing
vessel.
8. Read the weight in mgs (m i ).
9. Repeat the test cycle until 10 measurements have
been recorded.
10. Convert the recorded masses (m i ) to volumes (V i )
by multiplying the mass with the correction factor
Z (Z-values in the table below):
V i = m i *Z
11. Calculate the mean volume (
⊽
= (∑V i )/10
12. For conformity evaluation calculate the systematic
error es of the measurement:
⊽
in µl: es =
or in %:
34
⊽
) delivered:
–V s V s = selected test volume
⊽
es = 100 ( –V s )/V s