Almost always NaCl in buffers - Why? - NaCl seems to be the gold standard in buffers - why? (Apr/26/2011 )
I was just wondering if anyone knows why (~250mM) NaCl is almost always the starting salt of choice for buffers. Why not ammonium sulfate, MgCl2, KCl, or KBr? Is it just because NaCl is the cheapest and most abundant? If so, are there other, more optimal, salts out there that we could be using? I have read a little about the hofmeister series, and from what I have read on that it seems as if using low concentrations of ammonium sulfate would be a good thing, but then again I am likely misinterpreting what I have read. That said, if any of you have advice or input regarding this please post away. It is welcomed.
Usually there is some salt, which, in my experience, is about 150 mM or approximately 0.9% = "normal saline" - i.e. iso-osmotic with that found in the body/cell. NaCl is used as it is cheap, abundant in the cell, and easy to calculate the osmolality.
Another convenient thing with using NaCl, if you need to adjust the pH of your buffer you can just use HCl or NaOH without adding other ions to the buffer that you might not want.
Na concentration is normally high in plasma and physically innert for normal condition, while other ion such as Mg, Ca can affect signal pathways.