Abstract :
A chemically modified carbon paste electrode with 3,4-tetra pyridinoporphirazinatocobalt(II) (Co(3,4 tppa) was applied to the determination of free cyanide ion. The electrode has a linear range between 1.5 * 10^-5 M and 1.0 * 10^-2 M with a Nernstian slope of 60 +- 1.5 mV/decade and its detection limit is 9 * 10^-6 M. The response time of electrode is 5 min. The proposed electrode was applied successfully for the determination of cyanide in commercially available spring water. Some anions, such as SCN-, I-, Cl-, Br- and oxalate that are usually serious interfering species for most of cyanide selective electrodes, did not have any interfering effect for this proposed electrode.