Question

You have a stock solution of FastGreen at a concentration of 10 ug/ml. What volumes of solution and water do you need to mix to obtain 400 ul of a 2 ng/ul solution? (Show ALL calculations)

Answer 1

Ans. Stock solution concentration = 10 µg/ mL

                                                            = 10 µg/ 1000 µL                    ; [1 mL = 1000 µL]

                                                            = 0.01 µg/ µL

Concentration of desired solution = 2 ng/ µL

                                                            = 0.002 µg/ µl                         ; [1 ng = 0.001 µL]      Required volume of desired solution = 400.0 µL

Now, using

(CIV1) stock solution = (C2V2) desired solution

Or, (0.01 µg/ µL) x V1 = (0.002 µg/ µl) x 400 µL

Or, V1 = [(0.002 µg/ µl) x 400 µL] / (0.01 µg/ µL)

Or, V1 = 0.8 µg / (0.01 µg/ µL)

Hence, V1 = 80 µL

Hence required volume of stock solution = 80 µL

Preparation: Take 80 µL stock solution in a sterile Eppendorf tube. Add 320 µL sterile distilled water to it to make the final volume upto 400.0 µL.