I am preparing sodium pyrophosphate solution as a phosphatase inhibitor. I ordered both Na4P2O7 · 10H2O (Sigma S6422) and Na4P2O7 (Sigma P8010) from sigma and both are insoluble in water but it is said Na4P2O7 is soluble in water at 0.5M according to the sigma website. I tried several times and failed.
Forgot to mention that I added 200uL of Acetic acid while it was on the stir plate to help dissolve the solution
It depends pretty much on the temperature of the water you are using, since the solubility is much smaller at lower temperatures. How much do you try to dissolve in which volume?
Hi Xianfeng
Have you tried using hot to boiling water? Also, acids easily dissolve sodium pyrophosphate. This is all I can think of at the moment as it should dissolve in water.
Hope you get the problem solved
Hi Christian, thanks for your response! I hope to prepare a solution of 0.5M and then add 1:200 to RIPA buffer. I put the "solution" into 60C water bath overnight and it still does not dissolve completely. So I think hot water does not help.
Hi Stephen,I tried to add some acetic acid to the solution and found Sodium pyrophosphate is dissolved in water. But I don't know what pH (how much acid and what acid) is good to keep the ability of phosphatase inhibition. In case acid addition leads to loss of function. I don't know. If you have more information (pubulished papers?) about acid addition please let me know. Thank you so much!
I am not sure whether the pH will affect the inhibitory effects of the sodium pyrophosphate itself. I would suggest testing your solution on a phosphatase if you have one in your lab. Also, if your solution is at an acidic pH it would through the pH alone inhibit the activity of alkaline phosphatases. However,, you can adjust the pH of your solution after dissolving it to the desired pH. The type of acid used, I have not been able to find studies on this either. I would suggest using a weak acid such as the acetic acid you used. Also, try and use it at as low a concentration as you can. Perhaps do a titration study of acetic acid into your sodium pyrophosphate and water mixture and see at what point do you find complete dissolving of the compound.
@Xianfeng: Ok, 0,5M can be pretty different, but lets assume you want to prepare 100ml solution. Then you need approx. 13,3 gr of sodium pyrophosphate. according to the wikipedia (unfortunately I have "Handbook of Chemistry and Physics" by hand, this would be most like more precise), the solubility of the compound at 25°C is between 6 and 7 grams per 100ml. At 100°C its already 42.2g. You are probably still below the solubility at that temperature. You could also add a little acetic acid to ease the dissolving.
I can confirm it easily dissolve in hot water, however, the compound resolidify whenever the solution cool down. Anyone having a solution to maintain the compund dissolved at +/- 25°C ?
I made 50mL of a .5M solution.
I weighed out 6.65g, added 40mL of diH20 to a 100mL beaker, added in the sodium pyrophosphate and placed on a heated stir plate, 95 degrees at about 600 rpm. Took roughly 45 min for everything to go into solution. Brought it up to 50mL in a graduated cylinder. Hope this helps
Forgot to mention that I added 200uL of Acetic acid while it was on the stir plate to help dissolve the solution
hi everyone,
thanks for this helpful discussion! just wondering Aldo, did you use undiluted acetic acid? does this help keep the Na4P2O7 in solution at RT? and do you store the solution at RT for longer periods of time?
many thanks!
Hi everyone. Is that possible use Sodium pyrophosphate dibasic (P8135/sigma) as phosphatase inhibitor?
Thanks
Hy everyone,
When preparing buffer for cell lysis for WB, I add the amount of Sodium Pyrophosphate salt required to make 100 mM solution just before to complete the volume with deionized water to my fresh made Lysis Buffer.
it works perfectly!
I hope I made myself clear :)
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