Buffer preparations and calculations help, show all work Perform the following c

Question

Buffer preparations and calculations help, show all work

Perform the following calculations using the compounds: Tris = 121.14g/m, NaCl = 58.4g/m, KCl = 74.5g/m, DTT = 154.3g/m

1) make a 500 ml solution of 25 mM Tris, 150 mM KCl, and 0.5 mM DTT

2) make a 1 L solution of 75 mM Tris, 450 mM KCl, and 1.5 mM DTT

3) using the solution that you made in question 2 above, you now need to use this buffer to set up a reaction in a small test tube. You need to dilute this sample into a final volume of 500 l such that the final buffer concentration is 25 mM Tris, 150 mM KCl, and 0.5 mM DTT. How would you do it? Then calculate the amount of each component you would predict to be in this final volume.

4) perform the same problem as in question 3 above, but this time your final volume will be 25 l.

Explanation / Answer

1)

For Tris:
(1000 mM ) (X ml) = (25 mM) (500 ml)
X ml = (25 mM) (500 ml)/ 1000 mM
X ml = 12.5 ml of 1 M Tris
For KCl:
(1000 mM) (X ml) = (150 mM) (1000 ml)
X ml = (150 mM) (500 ml)/ 1000 mM
X ml = 75 ml of 1M KCl
For DTT:
(1000 mM) (X ml) = (0.5 mM) (500 ml)
X ml = (0.5 mM) (500 ml)/ 1000 mM
X ml = 0.25 ml of 1M DTT

12.5 ml Tris + 75 ml KCl + 0.25 ml DTT = 87.75 ml. This is the total amount of initial volumes to be used.

500 ml - 87.75 ml = 412.25 ml of diluent

2)

Similarly, for 1 L sloution

For Tris:
(1000 mM ) (X ml) = (75 mM) (1000 ml)
X ml = (75 mM) (1000 ml)/ 1000 mM
X ml = 75 ml of 1 M Tris
For KCl:
(1000 mM) (X ml) = (450 mM) (1000 ml)
X ml = (450 mM) (1000 ml)/ 1000 mM
X ml = 450 ml of 1M KCl
For DTT:
(1000 mM) (X ml) = (1.5 mM) (500 ml)
X ml = (1.5 mM) (1000 ml)/ 1000 mM
X ml = 1.5 ml of 1M DTT

So, diluent= 1000 ml - final volume of initials used in ml

Diluent= 1000 ml-(450+75+1.5) ml

Diluent= 473.5 ml

3) proceeding in the same as in 2nd question we have

For tris

X ml=(25 mM)(5 ml) /1000 mm

X ml=0.125 ml of 1M tris

For KCl

X ml = (150 mm) ( 5 ml) /1000 mm

X ml= 0.375 ml of 1 M KCl

For DTT

X ml=(0.5 mm) (5 ml) /1000 mm

X ml= 0.0025 ml of 1 M DTT

So, diluent = 5 ml - (final volumes of the initials used in ml)

Diluent =5 ml - (0.375+0.125+0.0025)ml

Diluent = 4.4975 ml

4) similarly proceeding in question 4 as in question 3 by only replacing the 5 ml with 2.5 ml.

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