SYNOPSISThe conducting polypyrrole chemically synthesized in water, using the variable concentrations of FeCl, and CuClz as oxidizing agents, was chemically and electrochemically characterized and compared with electrochemically generated polypyrrole. According to the results of elemental analysis and counter ion determinations, it can be concluded that a mixture of dimer and trimer was obtained using CuClZ, i.e., a dimer composition using FeC13 as an oxidant. Cyclic voltammetric studies of polypyrrole obtained by using FeC13 as an oxidant showed no evidence of polypyrrole decomposition after repetitive cycling. The voltammograms showed also that after the oxidation reaction a high capacitive current remained, confirming the assumption that the capacitive current is intrinsically associated with polypyrrole, irrespective of the way of its preparation. Cyclic voltammogram of the polypyrrole synthesized by oxidation with CuClz showed different shape, probably influenced by the presence of copper ions incorporated in polymers. 0 1992 John Wiley & Sons, Inc.

The simple PVC-based membrane containing N,N',N'',N'''-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc) as an ionophore and dibutyl phthalate as a plasticizer, directly coated on a glassy carbon electrode was examined as a new sensor for Cu 2þ ions. The potential response was linear within the concentration range of 1.0 Â 10 À1 -1.0 Â 10 À6 M with a Nernstian slope of 28.8 mV/decade and detection limit of 7.0 Â 10 À7 M. The electrode was used in aqueous solutions over a wide pH range (1.3 -6). The sensor exhibited excellent selectivity for Cu 2þ ion over a number of cations and was successfully used in its determination in real samples.

Mixed ligand dinuclear copper(II) complexes of the general formula [Cu2(Rdtc)tpmc)](ClO4)3 with octaazamacrocyclic ligand tpmc and four different heterocyclic dithiocarbamate ligands Rdtc−, as well as the complexes [Cu2(tpmc)](ClO4)4 and [Cu(tpmc)](ClO4)2⋅2H2O were studied in aqueous NaClO4 and HClO4 solutions by cyclic voltammetry on glassy carbon electrode. The electrochemical properties of the ligands and Cu(II) complexes were correlated with their electronic structure. Conductometric experiments showed different stoichiometry in complexation of tpmc with Cu2+ ions and transport of ions in acetonitrile and in aqueous media. These studies clarified the application of this macrocyclic ligand as ionophore in a PVC membrane copper(II) selective electrode and contributed elucidation of its sensor properties.

An all solid-state Ag(I) ion-selective electrode has been prepared by simply immersing a glassy carbon rod coated with PVCAc, which contained plasticizer and additive but no ionophore, into the AgNO 3 solution. The response of the electrode was linear with a Nernstian slope of 60.25 mV/decade within the concentration range from 1 10 À1 to 1 10 À5 M and with a detection limit of 4.25 10 À6 M. The stability as an effect of various cations was defined. The electrode is suitable for use in high acidic solutions (pH < 1 to 7) and has successfully been applied for the determination of silver(I) concentrations in different samples.