4 replies to this topic

[R3search3R]

Hi all,

I have an issue regarding production of sodium phosphate buffer.

I have been asked to make 2x sodium phosphate buffer pH8.0. I have found protocols which combine 1M monobasic and 1M dibasic reagents and adjust to pH using either or which I have made.

My issue is how do I know what 2x is? and or, what would the combination of the two 1M solutions produce in 'X'. Im hoping to make a stock like PBS comes in @ 10x and then dilute down from there.

Hope this makes sense

[bob1]

2x is twice the concentration you would normally use - this will depend on your protocol, but typical phosphate solutions are 0.1 M made by mixing mono and di-sodium phosphate 0.2 M solutions with water.

[El Crazy Xabi]

bob1, 0.1M is for the 10X stock, usually 10mM for use

[bob1]

El Crazy - depends on the application, but you are right, it is a stock usually.

[mdfenko]

R3search3R, on 15 November 2012 - 03:12 AM, said:

what would the combination of the two 1M solutions produce in 'X'. Im hoping to make a stock like PBS comes in @ 10x and then dilute down from there.

as the others have pointed out, "x" depends on the protocol, but, in answer to your question of combining two 1M solutions, the beauty of using equimolar acid and base components of a buffer is that no matter how much you add of one or the other the concentration of the buffering component remains the same. so, by mixing two 1M components your buffer solution will be 1M.