Question

In order to make a Chromatin Immunoprecipitation (ChIP) dilution buffer, you need to make some concentrated stock solutions first. Describe how to make the following solution: make 500 mL of a 1 M Tris-Cl pH 8.0 stock solution (Tris base is a solid with a FW: 121.14 g/mol) 


Answer 1

1.To prepare, 500 ml of 1 M Tris.Cl solution, weigh 121.14 gram Tris base (molecular weight = 121.14) and transfer to a 1 liter beaker/conical flask.

2.Dissolve tris base in 400 ml deionized/Milli-Q water using magnetic stirrer.
One can use manual shaking using a glass pipette. Magnetic stirrer makes the dissolving process easy and convenient.Do not dissolve in 500 ml of deionized/Milli-Q water. In most cases, especially when the solute amount is large, the volume of the solution increases when solute is dissolved in solvent. It is essential to dissolve the solute in a small volume of solvent (e.g., 80% of the required volume). After the solute is completely dissolved and pH is adjusted (if required), make up the correct volume with the solvent.

3.Adjust the pH 8.0 with concentrated HCl. ( for 1M Tris cl the pH is > 10 so HCI is added to bring it to 8)

4.Adjust the volume to 500 ml with deionized/Milli-Q water.

i hope im correct