Page 128 - The Veterinary Laboratory and Field Manual 3rd Edition

The selection, use, maintenance and quality control of laboratory equipment and supplies 97

Figure 2.66 Pipette graduated. Photo: Willy Figure 2.67 Pipette volumetric close up. Photo:
Schauwers, Provincial Institute for Hygiene, Willy Schauwers, Provincial Institute for Hygiene,
Antwerp, Belgium. Antwerp, Belgium.

HandLInG oF PIPEttES contact with the inclining inner surface of
Pipettes calibrated ‘to deliver’ (‘TD, Ex’). the receiving vessel
• the pipette is held nearly vertical, the tip is
• Filling:
placed in contact with the inclining inner
• a pipette bulb or pipettor (manual pi-pump surface of the receiving vessel
or electric/battery operated pipette-aid) is • when the meniscus comes to a rest in the
attached to the upper end and the liquid tip, the waiting time of 5 s begins (class
is suctioned up into the pipette ±5 mm AS only)
above the marking on the stem above the • after the waiting time, draw the pipette
centre bulb upwards along the inner wall of the receiv-
• wipe off any remaining liquid with a tissue ing vessel through a distance of about
at the outside of the tip 10 mm (Figure 2.67)
• set the meniscus • pipettes should be rinsed with tap water
• wipe off any drop of fluid adhering to the (by using a water jet pump) immediately
tip. after use.

• Delivering:
• hold the pipette vertically and deliver
the liquid with the tip of the pipette in

Vet Lab.indb 97 26/03/2019 10:25