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 250 ml solution of 25 mM Tris, 150 mM KCl, and 0.5 mM DTT

2) make a 4 L solution of 50 mM Tris, 100 mM NaCl, and 0.5 mM DTT

3) make a 2 L solution of 30 mM Tris, 75 mM NaCl, and 0.5 mM DTT

4) How will you make a 2 L buffer of 25 mM Tris-HCl pH 8.8, 0.2 M Glycine, 20% methanol from their stock solutions of 1 M Tris (pH 8.8), 0.75 M Glycine and 100% methanol? Describe step by step procedures and show all work for making this buffer.

Explanation / Answer

Molecular weight of
Tris = 121.14g/m,
NaCl = 58.4g/m,
KCl = 74.5g/m,
DTT = 154.3g/m

1) make a 250 ml solution of 25 mM Tris, 150 mM KCl, and 0.5 mM DTT
    Molarity = weight in g/ mol.wt x volume in L
  
So, we need to calculate how many grams of Tris (0.025 M), KCl (0.150M), DTT (0.0005M) required to
dissolve in 0.250 L of water.

For Tris; 0.025 = wt/ 121.14 x 0.25 L;
           wt = 0.757 g
For KCl: 0.15 = wt/ 74.5 x 0.25 L
           wt = 2.793 g
For DDT: 0.0005 = wt/154.3 x 0.25
        wt = 0.019 g
      
Weight 0.757 g of Tris, 2.793 g of KCl and 0.019 g of DDT and take them into standard 250 mL flask. Dissolve the above salts by adding some water and then fill the flask to the specified mark on the standard flask.
This solution will be your 250 ml solution of 25 mM Tris, 150 mM KCl, and 0.5 mM DTT

2) 2) make a 4 L solution of 50 mM Tris, 100 mM NaCl, and 0.5 mM DTT

Similarly we can calculate for the above;

For Tris; 0.05 = wt/ 121.14 x4L
               wt = 24.228 g
For NaCL: 0.100 = wt/ 58.4 x 4 L
           wt = 23.36 g
For DDT: 0.0005 = wt/154.3 x 4 L
        wt = 0.3086 g
      
Weight 24.228 g of Tris, 23.36 g of NaCl and 0.3086 g of DDT and take them into standard 4L flask. Dissolve the salts by adding some water and after dissolution fill the flask to the specified mark on the standard flask.
This solution will be your 4 L solution of 50 mM Tris, 100 mM NaCl, and 0.5 mM DTT. I am not sure whether you will get 4L standard flask, so, just dissolve the above salts into 4 L water.

3) make a 2 L solution of 30 mM Tris, 75 mM NaCl, and 0.5 mM DTT

Similarly, we can calculate for the above;

For Tris; 0.03 = wt/ 121.14 x2L
               wt = 7.268 g
For NaCL: 0.075 = wt/ 58.4 x 2 L
           wt = 8.76 g
For DDT: 0.0005 = wt/154.3 x 2 L
        wt = 0.1543 g
      
Weight 7.268 g of Tris, 8.76 g of NaCl and 0.1543 g of DDT and take them into standard 2L flask. Dissolve the salts by adding some water and after dissolution fill the flask to the specified mark on the standard flask.
This solution will be your 2 L solution of 30 mM Tris, 75 mM NaCl, and 0.5 mM DTT.

4) How will you make a 2 L buffer of 25 mM Tris-HCl pH 8.8, 0.2 M Glycine, 20% methanol from their stock
solutions of 1 M Tris (pH 8.8), 0.75 M Glycine and 100% methanol? Describe step by step procedures and
show all work for making this buffer.

For Tris;
M1 = 1    M2 = 0.025
V1 = ?     V2 = 2L
M1xV1 = M2xV2
V1 = M2xV2/ M1 = 0.025 x 2 L / 1 = 0.050 L = 50 ml

For Glycine;

M1 = 0.75    M2 = 0.2
V1 = ?     V2 = 2L
M1xV1 = M2xV2
V1 = M2xV2/ M1 = 0.2 x 2 L / 0.75 = 0.533 L = 533 ml

For methanol;

% v/v = (volume of solute/volume of solution)x100
   20 = (Volume of methanol / 2 L) x100
   volume of methano = 40/100 = 0.4 L = 400 mL of methanol

   So to get the required concentration we need to take 50 mL of Tris-HCl pH 8.8, 533 mL Glycine,   and 400 mL methanol into a 2L standard flask fill up the specified mark on standard flask with water
. This gives you the required solution of 2 L buffer of 25 mM Tris-HCl pH 8.8, 0.2 M Glycine, 20% methanol
      
              

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