Preventing contamination and guaranteeing exact and accurate results require proper pipette tip loading. To properly load a pipette tip, follow these steps:

1. Select the appropriate pipette tip. Make sure the tip on the pipette you choose fits the type of pipette and volume of liquid you are transferring.

2. Hold the pipette tip firmly by its flange. The wider part of the pipette tip is called the flange. Hold the pipette tip by the flange to ensure a good seal and prevent contamination.

3. Slide the pipette shaft and tip into place. Make sure the pipette tip and shaft are inserted all the way. There should be no separation of the pipette tip and shaft.

4. To establish a vacuum, gently apply pressure on the plunger. By doing this, you can ensure that the liquid sample and pipette tip will be securely sealed.

5. To aspirate the liquid sample, release the plunger. Be cautious not to breathe in too much of the liquid sample. The liquid level at the pipette tip should be slightly less than the graduation mark.

6. Press the plunger slowly to dispense the liquid sample. Be cautious not to administer the liquid sample too quickly as this could lead to inaccurate results.

7. Press the ejector button to remove the pipette tip. The tip should be able to be neatly ejected from the pipette shaft.

By following these procedures, you can ensure that your pipette tips are loaded correctly and that your results are accurate and precise.