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A Selective Membrane Electrode for Thiocyanate Ion Based on a Bis‐taurine‐salicylic Binuclear Copper(II) Complex as Ionophore
Author(s) -
FuChang Wang,
YaQin Chai,
Ruo Yuan,
ChunHua Chen,
JianYuan Dai,
Lan Xu
Publication year - 2005
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.200590865
Subject(s) - chemistry , thiocyanate , potentiometric titration , ionophore , selectivity , inorganic chemistry , copper , ion selective electrode , membrane , electrode , organic chemistry , biochemistry , catalysis
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 SCN −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.