Question

You are preparing a 4-tube series of a 5-fold serial dilution. If Tube #1 contains 500 µL of undiluted stock solution, then how much diluent should be added to Tubes #2 - #4?a. 100 µL

b. 250 µL
c. 400 µL
d. 500 µL

Answer 1

For a 5-fold serial dilution with a starting volume of 500 µL in tube #1, you would add 500 µL of diluent to tubes #2, #3, and #4 to continue the proper dilution process.

Step-by-step explanation:

You are preparing a 4-tube series of a 5-fold serial dilution. To proceed with this dilution, a fixed amount of stock solution will be transferred to the first tube and then diluted with a solvent. If tube #1 already contains 500 µL of the stock solution, you would need to perform a 5-fold dilution by adding four times the volume of stock solution as diluent to achieve the correct dilution factor. In other words, since you have 500 µL of stock solution in tube #1, you would add 2000 µL (500 µL multiplied by 4) of diluent to get a 5-fold dilution. However, for practicality, you would transfer 100 µL to tube #2 and then add 400 µL of diluent, then repeat this process for tubes #3 and #4. Thus, the correct amount of diluent to be added to tubes #2 - #4 is 500 µL.