Tips for Proper Use of a Micropipette

Introduction

• Presenter: Ben Benson from Sanford Promise Community Lab
• Purpose: Share tips for proper micropipette use to increase accuracy and confidence in the lab

Initial Preparation

• Personal Protective Equipment (PPE):
  • Wear appropriate PPE based on lab hazards
• Lab Space Setup:
  • Ensure all samples and containers are within arm’s reach
  • Clean and clear workspace
  • Have waste containers for used tips
  • Avoid reaching over samples

Understanding the Micropipette

• Basic Parts:
  • Plunger: Press to pick up and dispense liquid
  • Ejector Button: Release used tip
  • Tip Holder: Where the disposable tip attaches
  • Volume Adjustment: Set desired volume
  • Volume Indicator: Displays the volume to be transferred
• Volume Range:
  • Typically measures 0.2 to 1000 microliters
  • Volume range is printed on the handle
  • Adjust volume by rotating the knob
  • Do not exceed pipette’s volume range

Handling the Micropipette

• Holding Technique:
  • Hook over the pointer finger
  • Hand forms a fist around it
  • Thumb operates plunger and eject buttons
• Two Stops:
  • First stop: Measures the liquid (gentle press)
  • Second stop: Ensures full expulsion of liquid (harder press)

Using Disposable Pipette Tips

• Purpose: Prevent contamination, ensure accurate measurement
• Attachment:
  • Attach by gently pressing into a tip box
  • Tip should not fall off easily
• Operation:
  • Depress plunger to first stop
  • Submerge tip just past liquid level
  • Release plunger gradually
  • Ensure all liquid is drawn in
  • Use a new tip for each new liquid or if contamination occurs
• Ejecting Tips:
  • Aim over waste container and press eject button
  • "When in doubt, throw it out" rule for tips

Review of Procedure

• To Aspirate Liquid:
  • Depress button to first stop
  • Submerge tip in liquid
  • Release button slowly
• To Dispense Liquid:
  • Place tip in recipient container
  • Press plunger past first stop
• Tip Ejection:
  • Press ejector button with tip inside waste container

Common Mistakes (Bloopers)

• Avoid Pressing Down Before Submerging Tip: Prevents air bubbles
• Do Not Slam Tip on Table: Avoids contamination
• Never Use Pipette Without Tip: Prevents liquid entering pipette body
• Do Not Exceed Pipette Volume Limits: Prevents damage and inaccuracies
• Do Not Jam Tip Repeatedly: Prevents pipette damage
• Do Not Release Button Abruptly: Ensures accurate volume dispensing
• Do Not Slam Plunger: Prevents unwanted spray

Conclusion

• Following these practices ensures safety, maintains equipment, and improves lab accuracy.