pipettes

• -  TD – quantity/volume of liquid contained in the pipet is equal to the capacity printed on the pipette minus the drainage holdback
• volume of TD pipete =

  volume of TC pipet plus drainage pullback error
• TC – quantity/volume of liquid contained in pipette is equal to the capacity printed on the pipet
• Volumetric – are designated to only measure one designated volume; also called “bulb” or “belly” pipets; can be TC/TD
• Serologic – etched with graduated measurements; user can determine volume pipetted up to the max capacity of pipet; common sizes are 1,5, 10 mL; can be TC/TD
• Positive displacement – piston enters in direct contact with the liquid; no air interference; enhances accuracy and precision for liquids that are too heavy/viscous to be displaced by air; allows aspiration of volatile liquids without evaporation; allows rapid pipetting without cavitation
• gravimetric - measured based on mass rather than volume