Overview
This lecture explains the correct use, settings, and handling of Finn or Gilson micropipettes—precision tools for measuring and transferring small liquid volumes in molecular biology labs.
Types and Ranges of Micropipettes
- Micropipettes are named by the maximum volume they can measure (e.g., P2, P20, P200, P1000).
- P2: 0.2–2 µL; P20: 2–20 µL; P200: 20–200 µL; P1000: 100–1000 µL.
- Each pipette is labeled on the push button with its model type.
Setting and Reading Volumes
- Pipettes have three number dials to set the desired volume using a thumb wheel or push button.
- The meaning of each digit depends on the pipette model—for example, 152 means 1.52 µL for P2, 15.2 µL for P20, and 152 µL for P200.
- Never use a pipette outside its specified volume range.
Choosing and Attaching Pipette Tips
- P20 and P200 use yellow tips; P1000 uses blue tips.
- Filter tips can prevent contamination.
- Attach tips firmly for an airtight seal but do not force.
Proper Pipetting Technique
- Depress the push button to the first stop to aspirate liquid; push past the first stop to expel all liquid.
- Insert the tip 2 mm into the liquid when drawing up.
- Release the button slowly to avoid air bubbles and ensure accuracy.
- When expelling, touch the tip to the side of the container for small volumes.
Maintenance and Safety Guidelines
- Always use a new, clean tip for each sample to avoid contamination.
- Discard tips using the tip ejector into appropriate waste.
- Never pipette without a tip or lay down a loaded pipette.
- Avoid letting liquid enter the pipette body to prevent damage and contamination.
- Do not exceed the pipette's designated volume range.
- Use controlled, gentle movements to maintain accuracy and avoid equipment damage.
Key Terms & Definitions
- Micropipette — a precision instrument for measuring and transferring small liquid volumes.
- First stop — the initial resistance point on the push button used to measure the set volume.
- Filter tip — a pipette tip with a built-in filter to prevent contamination.
- Volume range — the specific minimum and maximum liquid volume a pipette can accurately measure.
Action Items / Next Steps
- Practice setting and reading volumes on different pipette models.
- Perform pipetting exercises using the correct tips and technique.
- Review pipette safety and maintenance protocols.