MOPS is a zwitterionic physiological buffer, with pH range 6.5 – 7.9. MOPS-containing electrophoresis buffer is suitable for RNA denaturing Agarose Gel Electrophoresis.
Reagents and solutions
MOPS free acid (C7H15NO4S, Molecular weight: 209.26)
Sodium acetate, anhydrous (CH3COONa, Molecular weight: 82.03)
0.5M EDTA, pH 7.5
Deionized / Milli-Q water
Equipment and disposables
Conical flask / Beaker
Note: Use ultrapure reagents and DEPC-treated water and glasswares if the MOPS Running Buffer is to be used for RNA electrophoresis.
Composition of 10X buffer
0.2 M MOPS
0.05 M Sodium Acetate
0.01 M EDTA
Composition of 1X buffer
0.02 M MOPS
0.005 M Sodium Acetate
0.001 M EDTA
Preparation of 1 L MOPS running buffer
Step 1: Weigh out 41.85 g MOPS free acid (C7H15NO4S, Molecular weight: 209.26) and 4.1 g Sodium acetate, anhydrous (CH3COONa, Molecular weight: 82.03). Transfer to a 2-liter beaker / conical flask. Add 800 ml deionized / Milli-Q water.
1. If you do not have 0.5M EDTA solution, you can also add 3.72 g of EDTA Disodium dihydrate (Molecular weight: 372.24). Since EDTA takes time to dissolve, it is convenient to add EDTA stock solution.
2. You can also use MOPS sodium salt in place of MOPS free acid. You need to add 46.25 g of MOPS sodium salt.
Do not dissolve all ingredients in 1000 ml of deionized / Milli-Q water. In most cases, solution volume increases when a large amount of solutes dissolve in a solvent.
It is always a good practice to dissolve solute(s) in a small volume of solvent (≈ 80% of the final solution volume). After the solute is completely dissolved and pH is adjusted, make up the correct volume with the solvent.
Step 2: Add 20 mL of 0.5M EDTA solution and mix the solution again.
Step 3: Adjust the pH to 7.0 using 10 N NaOH solution.
Step 4: Adjust the volume to 1000 ml with deionized/Milli-Q water. Mix it again.
Step 5: Sterilize the solution by filtering through a sterile filter unit containing a membrane with porosity 0.22 µm or less.
We don’t recommend autoclaving the solution.
Freshly prepared solution will appear clear colourless liquid which can turn into yellowish with time.
Stored the solution at 4° C in a brown bottle
Protect the solution from light.
|Follow the table to prepare a 10x MOPS electrophoresis buffer of various volumes.|
|Reagents / Volume||100 ml||250 ml||500 ml||1000 ml|
|MOPS free acid||4.185 g||10.46 g||20.93 g||41.85 g|
|Sodium acetate, anhydrous||0.41 g||1.025 g||2.05 g||4.1 g|
|0.5 M EDTA (pH 8.0)||2 ml||5 ml||10 ml||20 ml|
|Water||Adjust to the final volume 100 ml||Adjust to the final volume 250 ml||Adjust to the final volume 500 ml||Adjust to the final volume 1000 ml|
- Cshprotocols: http://cshprotocols.cshlp.org/content/2015/2/pdb.rec083550.full?rss=1
- Cshprotocols: http://cshprotocols.cshlp.org/content/2006/1/pdb.rec8332.full
- Goldbio : https://www.goldbio.com/documents/2889/MOPS%20Running%20Buffer%20Preparation%20Protocol.pdf