Question

The first step in the procedure asks you to prepare five dilutions of the protein standard (BSA) in the range of 0.2 to 1.0 mg/ml. For each concentration, a volume of 1.0 mL should be prepared. Describe how you will prepare these standards using a stock solution of BSA that is 2.0 mg/ml.

Answer 1

A/C to M1V1 = M2V2

V1 = M2V2/M1

M1 = 2 mg/mL , V2 = 1 mL,

Five dilutions in the range 0.2 to 1means that each dilution differ by 0.2 and concentrations are 0.2, 0.4, 0.6, 0.8 and 1 mg /mL.

For 0.2 mg/mL:

V1 = 0.2 x 1/ 2 = 0.1 mL

For 0.4 mg /mL:

V1 = 0.4 x 1/ 2 = 0.2 mL

For 0.6 mg /mL

V1 = 0.6 x 1/2 = 0.3 mL

For 0.8 mg/mL

V1 = 0.8 x 1/ 2 = 0.4 mg/mL

For 1mg /mL

V1 = 1x1/ 2 = 0.5 mg /mL

To prepare 0.2, 0.4, 0.6, 0 8 and 1 mg/mL of solutions we need to dissolve 0.1,0.2 0.3, 0.4 and 0.5 mL of stock solution in 1 mL of solvent (water) respectively.