Simultaneous determination of rhodium and gold by derivative spectrophotometric method

Creative Commons License

Turak F.

REVIEWS IN ANALYTICAL CHEMISTRY, vol.22, no.3, pp.157-165, 2003 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 22 Issue: 3
  • Publication Date: 2003
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.157-165
  • Yıldız Technical University Affiliated: Yes


Rhodanine and its derivatives are used for the quantitative analysis of silver, gold (III), palladium (II), copper (1) and (II), rhodium (III), mercury and other ions / I/. p-dimethylaminobenzylidene rhodanine (p-DABR) was first proposed as an analytical reagent by Feigl. It is widely used for separation and spectrophotometric determination of Ag and Pd. It is also used as a reagent for Au, Hg and Pt, for indirect determination of CI" and CN", as an acid-base indicator in acetic acid medium, and in selective resins /2,3/. Gelatin or gum Arabic is utilized to stabilize the formed complexes. Drawbacks of these methods are the limited solubility of the reagent and instability of the reaction products /4/. On the other hand, surfactants and micellar systems are currently used to improve the sensitivity and/or selectivity of the spectrophotometric methods for metal ion determination. Such systems manipulate the solubility and micro environment of reagents and analytes, and control the reactivity, equilibrium and pathway of chemical or photochemical processes /5,6/. In the present paper, the reactions of Au (III) and Rh (III) with p-DABR in the presence of cationic [cetyltrimethylammonium bromide, CTAB] surfactant have been studied. Simultaneous photometric determination of Au (III) and Rh (III) is hampered due to spectral overlap of their complexes. In such cases spectrophotometry coupled with derivative techniques is useful in analysis of such mixtures Π-91. In this work derivative spectrophotometry was also used to improve the sensitivity and selectivity /ΙΟ,II/. As the proposed methods are practically free from interferences, they have been applied to Rh (III) and Au (III) determination in synthetic samples.