Extraction preconcentration of platinum and ruthenium using high molecular weight amines prior to simultaneous determination by derivative spectrophotometry

Platinum and ruthenium can be simultaneously extracted from hydrochloric acid solution by high molecular weight amines (trioctylamine (TOA) or diantipyrylmethane (DAM) in 1,2-dichloroethane) after preliminary conversion into the complexes with SnCl3 ligands. The determination of both metals in the presence of each other in organic solutions of the formed ion-pairs can be accomplished by applying derivative spectrophotometry. The values of the second derivative spectra at 395 nm and 437 nm, calculated with the 2-nd degree polynomial and 75 points correspond to the concentration of platinum associated with TOA and DAM, respectively. The value of the second derivatives at 497 nm and 463 nm can make a basis of the determination of ruthenium in the presence of platinum in the form of ion-pairs with TOA and DAM, respectively. The use of TOA as extractant ensures higher precision and accuracy of the determination of platinum and ruthenium by derivative spectrophotometry. RSD of the results of the determination of metals in synthetic mixtures does not exceed 2.7 % and 3.2 % for platinum and ruthenium, respectively.