A selective modified carbon paste electrode for determination of cyanide using tetra-3,4-pyridinoporphyrazinatocobalt(II)

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 x 10(-5) M and 1.0 x 10(-2) M with a Nernstian slope of 60 +/- 1.5 mV/decade and its detection limit is 9 x 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. (c) 2005 Elsevier B.V. All rights reserved.