Adsorptive determination of copper(II) in solution as an ion-pair of bisneocuproinecopper(I) and dodecylsulfate 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 adsorbs on the quartz plate of an electrode-separated piezoelectric quartz 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 concentration of copper(II) in sample solution over the range 2.0-15 mu M. The relative standard deviation at 5.0 mu M (n=10) was 6.9%. The adsorbed copper(I) complex could be removed from the quartz plate with a 50% 2-propanol aqueous solution. The continuous determination of copper(II) without the eluent could be performed with a shorter time and good repeatability. (C) 1998 Elsevier Science B.V. All rights reserved.