Question

Folic acid is available from the manufacturer in vials of 5 mg in 1 mL. Prepare 30 mL of a folic acid dilution in a 100 mcg/mL concentration. How much folic acid (in milliliters) do you need

Answer 1

Ans. Given,     Stock folic acid solution = 5.0 mg/ mL

Desired volume of diluted solution = 30.0 mL

Desired concentration of diluted solution = 100 mcg/ mL                    ; [1 mg = 1000 mcg]

= 0.1 mg/mL

Now, using-

            C1V1 (stock solution) = C2V2 (diluted solution)

            Or, (5.0 mg/ mL) x V1 = (0.1 mg/ mL) x 30.0 mL

            Or, V1 = (0.1 mg/ mL) x 30.0 mL / (5.0 mg/ mL)

            Hence, V1 = 0.60 mL

Hence, required volume of stock folic acid solution = 0.60 mL