Use of the sulfide mineral pyrite as electrochemical sensor in non-aqueous solutions: potentiometric titration of weak acids in acetonitrile, propionitrile and benzonitrile.

Natural monocrystalline pyrite as a new indicator electrode for the potentiometric titration of weak acids in acetonitrile, propionitrile and benzonitrile was studied. The investigated electrode showed a linear dynamic response for p-toluenesulfonic acid concentrations in the range from 0.1 to 0.