Abstract

A simple, rapid, and sensitive method has been developed for the simultaneous determination of trace amounts of copper and silver using 1-phenyl1,2-propanedione-2-oximethiosemicarbazone (PPDOT) as a chromogenic reagent. The proposed method was based on retention and preconcentration of the complexes Cu(II)-PPDOT and Ag(I)-PPDOT on a solid phase in acid medium. The complexes were quantitatively retained in the cation exchanger SP Sephadex C25, and the analytical measurements were executed directly in the solid phase by derivative spectrophotometry. In this simultaneous determination, the second derivative and the zero crossing method were used. The determination of copper and silver was carried out to 321.0 and 427.0 nm, respectively. In order to obtain quantitative recoveries of the metal ions, various experimental analytical parameters, such as pH, stirring time, volume, and amount of solid phase, were optimized. The effect of interfering ions on the determination was described. The recovery values for Cu(II) and Ag(I) were found to be >98%, and the relative standard deviation was <2%. The detection limits (3a criterion) for Cu(II) and Ag(I) were found to be 0.9 × 10-8 and 13 & 10-8 M, respectively. The developed method was utilized for preconcentration and determination of Cu(II) and Ag(I) in industrial effluents and natural water samples. The results were consistent with those provided by inductively coupled plasma/mass spectrometry.