Abstract
A spectrophotometric method for the determination of palladium, tellurium and iridium from nitric acid media after extraction of their 2-mercapto-4-methyl-5-phenylazopyrimidine complexes into molten naphthalene has been develop and possible synergistic effects have been investigated. Dioxane, methanol, ethanol, 1-propanol, acetone and acetonitrile are used as the organic component of the mixed (polar) phase; the maximum enhancement is obtained with acetonitrile. Solid naphthalene containing the metal complex is separated by filtration and dissolved in chloroform; trace amounts of these metals are determined spectrophotometricaly. Beer′s law is obeyed in the following concentration ranges: Pd, 7.0-84.0μg; Te, 10.0-125.0μg and Ir, 6.0-90.0μg/10ml of the final solution. The molar absorptivities (dm3 mol-1 cm-1) and Sandell′s sensitivities (μg cm-2) were calculated: Pd(II)=2.05×104 and 0.0052, Te(IV)=1.84×104 and 0.0069 and Ir(III)=0.95×104 and 0.020, respectively. Ten replicate analyses containing 12.5μg of Pd(II), 21.0μg of Te(IV) and 85.0μg of Ir(III) gave mean absorbances of 0.241, 0.302 and 0.420 with relative standard deviations of 0.53, 0.36 and 0.85%, respectively. The interference of various ions was studied, and conditions were developed for the determination of these metals in certain alloys and synthetic mixtures.
