3. Procedure
(1) Determine the water temperature and record it.
(2) Place a beaker filled with distilled water into analytic balance and close the door of balance waiting for
equilibrium of inner vapor
(3) Place a plastic medicine cup on the pan and adjust the weight to zero.
(4) Put a tip onto the pipette and set the volume which is to be tested.
(5) Pre-rinse the tip: aspirate and dispense the setting volume three times and press the push – button on
the second stop to remove any remaining liquid.
(6) Press the push-button to the first positive stop. Hold the pipette vertically, immerse the tip so that 1-4
mm in the liquid and release the push button slowly and smoothly to aspirate the liquid.
(7) Wait one second and withdraw the tip from the liquid.
(8) Wipe any droplets away from the outside of the tip using a kimwipe.
(9) Place the end of the tip against the inside wall of the plastic cup at an angle of 10-40 °.
(10) Press the push-button smoothly to the first stop. Wait one second, change new site and press the
push-button on the second stop.
(11) Keeping the push-button press to the end, remove the pipette by drawing the tip along the inside
2
surface of the plastic cup and release the push button.
(12) Close the door of balance and record the value on the balance display after it has stabilized.
(13) Repeat step (6) to (12) 14 times ( the weight display of balance should be adjusted to zero every time)
(14) Eject the tip.
(15) Pipette should be calibrated every three months routinely.