[baseball07]

Hi everyone.  Is PBS buffer a monovalent salt solution?  Which ion in PBS would you use to measure the ion concentration?  K,Cl, Na???  Im looking to characterize the debye length as a function of ionic salt concentration in PBS.

[Yggdrasil]

PBS is a mixture of salts, not all of which are monovalent (specifically, it contains a significant amount of HPO₃^2- ions).  The typical formulation is 137 mM NaCl, 2.7 mM KCl, 10 mM Sodium Phosphate dibasic, 2 mM Potassium Phosphate monobasic (giving a pH of 7.4).