20X SSPE Buffer Recipe
This recipe prepares 1 L of 20X SSPE containing 3 M NaCl, 200 mM sodium phosphate, and 20 mM EDTA at pH 7.4.
20X SSPE composition
| Component | Amount for 1 L | 20X stock | Final 1X |
|---|---|---|---|
| NaCl | 175.3 g | 3 M | 150 mM |
| NaH₂PO₄ · H₂O | 27.6 g | 200 mM | 10 mM |
| Na₂EDTA · 2H₂O | 7.4 g | 20 mM | 1 mM |
How to prepare 1 L of 20X SSPE
- Add approximately 800 mL of ultrapure or deionized water to a suitable vessel.
- While stirring, add 175.3 g of NaCl, 27.6 g of NaH₂PO₄ · H₂O, and 7.4 g of Na₂EDTA · 2H₂O.
- Continue stirring until all components are completely dissolved.
- Adjust the pH to 7.4 with 10 M NaOH.
- Add ultrapure or deionized water until the final total volume is 1.00 L.
- Mix thoroughly to ensure the solution is uniform.
- Sterilize by autoclaving if required for the intended application.
- Store at room temperature in a tightly closed container and label it with the solution name and concentration, preparation date, and sterility information.
Note: Adjust the pH before bringing the solution to its final volume. Do not dissolve the components in a full 1 L of water, as this would produce a final volume greater than 1 L.
Scaled quantities
| Final volume | NaCl | NaH₂PO₄ · H₂O | Na₂EDTA · 2H₂O |
|---|---|---|---|
| 100 mL | 17.53 g | 2.76 g | 0.74 g |
| 250 mL | 43.83 g | 6.90 g | 1.85 g |
| 500 mL | 87.65 g | 13.8 g | 3.70 g |
| 1 L | 175.3 g | 27.6 g | 7.4 g |
Working concentration and use
To prepare 1X SSPE, dilute one volume of 20X stock with 19 volumes of water. The resulting solution contains 150 mM NaCl, 10 mM sodium phosphate, and 1 mM EDTA and is commonly used for nucleic acid hybridization and washing.