COPPER(II) SENSITIVE ELECTRODE BASED ON N ONSTOICHIOMETRIC COMPOUND TIO2-SIGMA

A new potentiometric sensor for copper(II) based on a titanium matrix is proposed, The sensor shows a Nernst response toward copper(II) whic h seems to originate from the nonstoichiometric compound TiO2-sigma la yer covering on the electrode surface according to the results of XPS spectra of the electrode surface and a.c. impedance of the electrochem ical system, The sensor owned a linear range from 10(-5)similar to 10( -2) mol/L with a detection limit of 5X10(-6) mol/L in 0.1 mol/L citric acid-sodium dihydrogen citrate buffer solution of pH 2.2, The standar d deviations determined by alternatively immersing the electrode in 1. 0X10(-4) and 1.0X10(-3) mol/L levels six limes are 1.7 mV and 1.4 mV, respectively, The e.m.f. drift in 10(-3) mol/L copper(II) solution is less than 2 mV within two hours, The sensor has an excellent selectivi ty for copper(II) with respect to many common divalent cations.