KP Buffer

Reagents (for 1L):

• KH₂PO₄ monobasic (Fisher, S80146-1) – 98.4g
• K₂HPO₄ dibasic (Sigma, P3786-500g) – 48.2g
• DI H₂O – 1 L.

Equipment:

• Vacuum Filtration System (VWR, 87006-068)

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Procedure:

1. Add about 800 ml of the water to a graduated cylinder containing a stir bar. Place on a magnetic stirrer.
2. Add both salts while the solution is stirring.
3. Add the remaining DI water to the 1L mark. Continuing stirring until the solution is clear.
4. Autoclaving this reagent causes it to crash out of solution. Instead, use a vacuum filtration system to remove any impurities from the solution. Practice sterile technique when removing the filter and applying the cap to the bottle.

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Figures

Figure 1.

Vacuum Filtration System (VRW 87006-068).

 

Image taken from VWR website