The simple, sensitive, and highly selective determination of palladium is based on the reaction between Pd(II) and 1,2-bis[methyl(2-aminocyclopentene carbodithioate)] ethane and extraction of the complex into dichloromethane. Beer's law is obeyed in the concentration range 0.19-10 mg ml 01 Pd. Relative standard deviations were 0.7-1.1%. The procedure has been successfully applied to the determination of palladium in different samples of catalysts. ᭧ 1997 Academic Press Palladium exists in various natural minerals, soils, and rocks and its abundance in the earth's crust has been calculated to be 0.01-0.02 ppm (1). This element is of immense importance to the electronic industry (2). It is used in grids for electronic tubes, for contact metals in printed circuits, and for high-quality spark plugs. Palladium is a suitable catalyst and is used for hydrogenation and dehydrogenation reactions. Palladium and its alloys also have widespread use in dental, medical devices, and jewelry manufacture.
The carcinogenicity of Pd(II) compounds in rats and mice and their toxicity to mammals, fish, and higher plants are causes for environmental concern (3). Therefore, these compounds usually considered environmental pollutants (4).
Various methods have been reported for the extraction of palladium from different media (5-12). However, the existing methods suffer from limitations such as insufficient selectivity, narrow pH, long extraction period, solvent dependence, high reagent blank, and temperature control. In some instances the extraction is not quantitative.
In the present study, a method is proposed for the selective and sensitive determination of palladium.
EXPERIMENTAL
Apparatus
Absorption spectra were recorded on a Beckman DK-2A ratio recording spectrophotometer using 1-cm glass cells. A Perkin-Elmer 35 spectrophotometer was used for the absorbance measurements at fixed wavelengths. A Corning pH meter Model 130 was used for pH measurements.
Reagents
All solutions were prepared from analytical-reagent-grade reagents. Triply distilled deionized water was used throughout. A standard palladium(II) solution (10 02 M) was