Hi everybody,

I am looking for a book or an article which deals with the solubilities of buffers. I often use mobile phases which contain high percentage of organic solvents (>50%). It will be very useful to know the maximum ratio of organic solvent which can be used without any precipitation occurs.
Thanks in advance for your help!

Depends on the type of phases...
Just perform "trial and error", i.e. mix both phases in different ratios in a test tube and you will see what happens...

Sorry, but I'm afraid there isn't any general tabulated data of the sort your requesting. As mentioned above, you're probably going to have to use laboratory experimentation on this one but at least I can give you some "guidelines" regarding electrolyte solubility in organic solvents:

1). The higher the dielectric constant of the solvent, the better its ability to solublize electrolytes.

2). Protic solvents generally solublize electrolytes better than aprotic solvents.

3). Ions with minimal hydration tend to dissolve at higher levels in solvents. The easiest way to get a sense of this is to look at the ion exchange affinity of the respective anion and cation in the salt. For example, since both lithium and fluoride elute early via anion and cation exchange, this salt will be difficult to dissolve in any organic solvent. Conversely, cesium iodide should be quite soluble in organic solvents as both of these ions elute late via cation and anion exchange, respectively.

I hope this helps.