Question

1× SDS Running Buffer
For this exercise, you will need to prepare 1 L of 1x SDS Running Buffer. The final
composition of this buffer is: 25 mM Tris, 200 mM Glycine pH 8.3, 0.1% (w/v) SDS
1. To a 1 L beaker, add 500 ml of distilled water. Place a magnetic stirring bar into
the beaker.
2. Calculate the amount of Tris base (MW 121.1) required give a final concentration of 25 mM. After checking the calculation with your demonstrator, weigh out the appropriate amount of Tris and add this to the beaker.
3. Calculate the amount of Glycine (MW 75.0) required give a final concentration of 200 mM. After checking the calculation with your demonstrator, weigh out the appropriate amount of Glycine and add this to the beaker.
4. Place the solution on the stirring plate until the above components have dissolved.
5. Calculate the volume of 10% (w/v) SDS to give a final concentration of 0.1% (w/v) and add to the beaker.
6. Using a graduated cylinder, adjust the volume to 1 L with distilled water.
7. Transfer the solution to a glass Schott bottle and check the pH using a pH strip.
Label the bottle appropriately

Answer 1

2. M = mols/L. You want 25 mM or 0.025 mols.
grams tris = mols tris x molar mass tris.

3. You want 200 mM or 0.2 mols.
grams glycine = mols glycine x molar mass glycine.

5. You have 10% stock solution of SDS. You want 0.1%. You want to dilute it 100 times and you want 1 L final solution so you take 10 mL of the stock and 10% x (10/1000) = 0.1%.