ADSORPTIVE DETERMINATION OF COPPER(II) IN SOLUTION AS AN ION-PAIR OF BISNEOCUPROINECOPPER(I) AND DODECYL-SULFATE IONS ON AN ELECTRODE-SEPARATED PIEZOELECTRIC QUARTZ-CRYSTAL

An ion-pair associate of a cationic copper(I) complex formed with 2,9- dimethyl-1,10-phenanthroline (neocuproine) and dodecylsulfate ions ads orbs on the quartz plate of an electrode-separated piezoelectric quart z crystal. The adsorptive behavior depends on pH and concentrations of neocuproine, hydroxylammonium chloride as reducing agent, and sodium dodecylsulfate. The frequency change is proportional to the concentrat ion of copper(II) in sample solution over the range 2.0-15 mu M. The r elative standard deviation at 5.0 mu M (n=10) was 6.9%. The adsorbed c opper(I) complex could be removed from the quartz plate with a 50% 2-p ropanol aqueous solution. The continuous determination of copper(II) w ithout the eluent could be performed with a shorter time and good repe atability. (C) 1998 Elsevier Science B.V. All rights reserved.