Highly salicylate-selective membrane electrode based on N,N′-bis-(furaldehyde)-glycine copper(II) complex as neutral carrier

A novel salicylate-selective poly(vinyl chloride) (PVC) membrane electrode based on N,N'-bis-(furaldehyde)-glycine copper(II) complex [Cu(II)-BFAG] as neutral carrier is reported, which exhibits anti-Hofmeister selectivity sequence: Sal(-) > ClO4- > SCN- > I- > NO3- > NO2- > Br- > Cl- > SO2- > SO42- and a near-Nernstian potential linear range for salicylate from 1.0 x 10(-1) to 4.0 x 10(-6) mol/L, with a detection limit of 8.0 x 10(-7) mol/L and a slope of -56.8 mV/pSal(-) in pH 5.0 of phosphate buffer solution at 25degreesC. The response mechanism is discussed in view of the A.C. impedance and the ultraviolet (UV) spectroscopy technique. The effects of the electrode membrane compositions and the experimental conditions were studied. The electrode based on copper(II) compound was applied to the determination of salicylate ion in drug pharmaceutical preparations with satisfactory results.