Goal Dilution of food coloring with fewest pipette tips poss

Goal: Dilution of food coloring with fewest pipette tips possible to minimize waste Exercise (Using forward pipetting method) Prepare the following micro tubes: Tube \"A\" 9 mu l of water Tube \"B\" 96 mu l of water Add 1 mu l of food coloring to Tube \"A\" Mix tube \"A\" and pipette 4 mu l of mixture of \"A\" into tube \"B\" What is the final dilution of tube \"B\" (x:y)? Exercise (Using reverse pipetting method) Prepare the following micro tubes: Tube \"C\" 98 mu l of water Tube \"D\" 975 mu l of water Add 2 mu l of food coloring to Tube \"C\" Mix tube \"C\" and pipette 25 mu l of mixture of \"C\" into tube \"D\" What is the final dilution of tube \"D\" (x:y)?

Solution

Answer:

Tube A dilution:

Fold Dilution = (Stock volume)/(Stock volume + diluent)

Fold Dilution=1uL/(1uL + 9uL) =1/10

Tbe B dilution:

Fold Dilution=4/(4 + 96) =1/100

Answer: Final dilution = 1/10 x 1/100 = 1/1000