A Selective Membrane Electrode for Thiocyanate Ion Based on a Bis-taurine-salicylic Binuclear Copper(II) Complex as Ionophore

✍ Scribed by Wang Fu-Chang; Chai Ya-Qin; Yuan Ruo; Chen Chun-Hua; Dai Jian-Yuan; Xu Lan

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 90 KB
• Volume: 23
• Category: Article
• ISSN: 0256-7660
• DOI: 10.1002/cjoc.200590865

✦ Synopsis

Abstract

The response characteristics of a new potentiometric membrane electrode with unique selectivity towards thiocyanate ion were reported. The electrode was prepared by incorporating bis‐taurine‐salicylic binuclear copper(II) complex into a plasticized PVC‐membrane. The resulting electrode exhibits anti‐Hofmeister selectivity sequence: SCN^−^>I^−^>ClO~4~^−^>Sal^−^>NO~3~^−^>NO~2~^−^>Br^−^>Cl^−^>SO~3~^−^>SO~4~^2−^ and a near‐Nernstian potential linear range for thiocyanate from 1.0Å×10^−1^ to 1.0Å×10^−6^ mol·L^‐1^ with a detection limit of 8.0Å×10^−7^ mol·L^−1^ and a slope of −56.5 mV/pc in phosphate buffer solution of pH 5.0 at 20°C. The UV/Vis spectra, IR spectroscopy and AC impedance studies showed that the excellent selectivity to thiocyanate was related to the unique interaction between the central metal and the analyte and a steric effect associated with the structure of the carrier. The electrode was successfully applied to the determination of thiocyanate in waste water and human urine samples.