Steady-state and flow-injection response of a metallic silver electrode for potentiometric detection of metal cyanide complex formartion

A metallic silver electrode provides a potentiometric response to Ag(I), Hg(II), Fe(III), Cu(II), Zn(II), Co(II) and Ni(II) ions, and large changes in the electrode potential of up to 400 mV are observed when these ions are injected into a 0.29 mM soulution of cyanide ion. Injection 10-μl aliquots into a reagent stream with a cyanide concentration of 0.1 mM is shown to give the expected sigmoidal-shaped response curve for peak height as a function of metal ion concentration. Sub-nanomole quantities of metal ions are detectable with a peak height of ca. 20 mV, depending on the cyanide concentration.