PBS magnesium buffer needed

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rogerkent
rogerkent's picture
PBS magnesium buffer needed

I need a phosphate buffered saline with magnesium and a PH of 5.5; can I make that easily, or can you please tell me who could make that up?

Many thanks

Roger.

PhilM
PhilM's picture
 Make 1 liter each of two

 Make 1 liter each of two separate 20X solutions

Solution 1  : 

348 mM Na2HPO4      46.86g
70 mM Na2H2PO4      9.66g

Solution 2:

70mM KCl                      5.2g
18mM MgCl2                 3.6g
2.74 M NaCl                 160g

Dilute 5 ml of each of solutions 1 & 2  in 90ml of dionized water to get 1X PBS

(check and adjust pH before you bring it up to full volume)

Do not refrigerate or the Mg will precipitate.

heehawmcduff
heehawmcduff's picture
Hi,

Hi,

Additionally, if you require very large volumes of it, Invitrogen offers a custom media/buffer service.

http://www.invitrogen.com/site/us/en/home/Products-and-Services/Applications/BioProduction/Custom-Media-Products.html

Not as much fun as making it up yourself however.

Sami Tuomivaara
Sami Tuomivaara's picture
Everyone,

Everyone,

I looked up from google and it looks like people really use phosphate buffer with pH around 5.5. I was wondering how much buffering capacity PBS has at that pH because the two lowest pKa's of phosphate are at 2.2 and 7.2?

Cheers,

rogerkent
rogerkent's picture
Very much appreciated.

Very much appreciated.
This approach looks like it will work (unlike mine).

Thanks.

Roger