Question

During the Purification of Lactate Dehydrogenase (LDH) experiment, you will need 50ml of buffer A150. Buffer A150 is 30mM Tris (pH 8.8) and 150mM NaCl. Given 1L of 1.5M Tris and 500ml of 5M NaCl, how much of each stock do you need to make 500ml of the A150 buffer?

Answer 1

Answer:

You will need 10 mL of stock Tris, 15mL of stock NaCl and enough water to bring the total volume to 500 mL.

Explanation:

The desired buffer contains:

• Total volume of 500 mL
• Tris 30mM
• NaCl 150mM

The stock solutions are:

• 1.5M = 1500mM Tris
• 5M = 5000mM NaCl

We can use the formula C1V1=C2V2 to calculate the volume of each stock required to prepare the buffer.

Tris

• C1= 1500 mM
• V1=?
• C2= 30mM
• V2= 500 mL

1500 mM x V1 = 30mM x 500 mL

V1 = (30mM x 500 mL) / 1500 mM

V1 = 10 mL

NaCl

• C1= 5000 mM
• V1=?
• C2= 150 mM
• v2= 500 mL

5000 mM x V1 = 150mM x 500 mL

V1 = (150 mM x 500 mL) / 5000 mM

V1 = 15 mL

You will need 10 mL of stock Tris, 15mL of stock NaCl and enough water to bring the total volume to 500 mL.