Question

I am asked to prepare a bradford assay in class using gamma-globulin (to determine the concentration of protein (a-La in original milk and multiple other samples) in order to do this I must prepare a strand curve (calibration curve) with samples containing known concentrations of gamma-globulin. The dilutions are made with a buffer A used in lab and the final volume of each dilution must be at least 200 uL. The standard curve will range from 0 to 60 mg/mL of the gamma-globulin (the stock solution is 60mg/mL).

My questions is how to I determine how to make these dilutions? Do I use M1V1=M2V2 to determine the volume I need, from the concentrations I want to make the samples?

Also how do I make an educated guess on what to make the concentration of my samples, in order to be able to properly compare them to the milk, supernatant, whey, and column fractions previously taken?

Answer 1

To make a fixed amount of a dilute solution from a stock solution, you can use the formula: C₁V₁ = C₂V₂where:

• V₁ = Volume of stock solution needed to make the new solution
• C₁ = Concentration of stock solution
• V₂ = Final volume of new solution
• C₂ = Final concentration of new solution
• Example: Make 5 mL of a 0.25 M solution from a 1 M solution.
• Formula: C₁V₁ = C₂V₂
• Plug values in: (V₁)(1 M) = (5 mL)(0.25 M)
• Rearrange: V₁ = [(5 mL)(0.25 M)] / (1 M)V₁ = 1.25 mL
• Answer: Place 1.25 mL of the 1 M solution into V₁-V₂ = 5 mL – 1.25 mL = 3.75 mL of diluent