Extraction and flame spectrophotometric determination of palladium and rhodium

Solvent extraction methods involving toluene, chloroform, 4-methyl-2-pentanone and pentyl acetate were studied for palladium and rhodium chelates. The palladiurn-salicylaldoxime chelate was extracted quantitatively into 4-methyl-2-pentanone at pH 3. The rhodium-diethyldithiocarbamate chelate was completely extracted into 4-methyl-2-pentanone at pH 8. The optimum combustion conditions for each of the organic extracts were then studied. The position of maximum emission intensity in the flame mantle was determined for each chelate and solvent system ; readings were taken at 363.5 mμ for palladium, and 369.2 mμ for rhodium. For palla-dium, when 4-methyl-2-pentanone was used instead of water as solvent, the emission intensity increased 21-fold. For rhodium, this kctone increased the sensitivity 27 times compared with water. A method is suggested for the separation and determination of palladium and rhodium in the same sample.