Question

Determine how much you need of each stock solution and distilled H2O to prepare the 80 ml mix:

Prepare 80 ml of 10% acrylamide, 0.2 M Tris-HCl ph of 8.9, 0.05% BIS.

Additionally, you have 20% Acrylamide (w/v), 2% Bis (v/v), and 2 M Tris-HCl pH of 8.9.

Answer 1

Use the dilution equation to calculate the initial concentrations for A and B. The dilution equation is

M₁*V₁ = M₂*V₂ where M₁ = concentration of stock solution; M₂ = initial concentration in the dilute solution; V₁ = volume of stock solution taken and V₂ = volume of final solution.

Acrylamide: V₁*(20% w/v) = (80 mL)*(10 % w/v)

====> V₁ = 40.0 mL.

BIS: V₁*(2% v/v) = (80 mL)*(0.2% v/v)

====> V₁ = 8.0 mL.

Tris-HCl, pH 8.9: V₁*(2.0 M) = (80 mL)*(0.2 M)

====> V₁ = 8.0 mL.

Take 40.0 mL of 20% (w/v) acrylamide, 8.0 mL of 2% (v/v) BIS and 8.0 mL of 2 M Tris-HCl, pH 8.9 buffer in a 80 mL volumetric flask and make up the volume by adding [80.0 – (40.0 + 8.0 + 8.0)] mL = 24.0 mL distilled water (ans).