New solid-state organic membrane based lead-selective micro-electrode

摘要

Microfabrication, characterization and analytical application of a new thin-film organic membrane based lead-selective micro-electrode have been elaborated. Prior to the fabrication of the assembly, the gold thin-film substrate has been electrochemically treated using a new technique. The developed micro-electrode based on tert-Butylcalix[4]arene-tetrakis(N,N-dimethylthioacetamide) as electroactive sensing material, carboxylated PVC as supporting matrix, 2-nitrophenyl octyl ether as solvent mediator and potassium tetrakiss (4-chlorophenyl) borate as lipophilic additive, respectively, provides a nearly Nernstian response (slope 28±0.5 mV/concentration decade) covering the concentration range 1×10~(-6) - 1×10~(-2) mole L~(-1) of Pb(II) ions with reasonable selectivity over some tested cations. The merits offered by the new microelectrode include simple fabrication, low cost as well as automation and integration feasibility. Moreover, the suggested microelectrode has been successfully applied for the determination of lead ions in some aqueous samples. These samples were also determined using inductively coupled plasma atomic emission spectroscopy (ICP-AES) for comparison. The proposed electrode offers a good accuracy (the average recovery was 95.5%), high precision (RSD was <3%), fast response time (<30 s.) and long life span (>4 months).