Journal of the Brazilian Chemical Society
On-line version ISSN 1678-4790
DONG, Xuechang et al. Simultaneous determination of palladium, platinum and rhodium by on-line column enrichment and HPLC with 2,4-dihydroxybenzylidenethiorhodanine as pre-column derivatization reagent. J. Braz. Chem. Soc. [online]. 2006, vol.17, n.1, pp. 189-193. ISSN 1678-4790. http://dx.doi.org/10.1590/S0103-50532006000100027.
A new method for the simultaneous determination of palladium, platinum and rhodium ions as metal-DHBTR chelates was developed. The palladium, platinum and rhodium ions were pre-column derivatized with 2,4-dihydroxybenzylidenethiorhodanine (DHBTR) to form colored chelates. The Pd-DHBTR, Pt-DHBTR and Rh-DHBTR chelates can be absorbed onto the front of the enrichment column when they were injected into the injector and sent to the enrichment column with a 0.05 mol L-1 sodium acetate-acetic acid buffer solution (pH 3.5) as mobile phase. After the enrichment had finished, by switching the six ports switching valve, the retained chelates were back-flushed by mobile phase and traveling towards the analytical column. These chelates separation on the analytical column was satisfactory with 62% (v/v) acetonitrile (containing 0.05 mol L-1 of pH 3.5 sodium acetate-acetic acid buffer salt and 0.1% (m/v) of tritonX-100) as mobile phase. The Limits of detection of palladium, platinum and rhodium are 3.6 ng L-1, 3.2 ng L-1 and 4.5 ng L-1, respectively. This method was applied to the determination of palladium, platinum and rhodium in water, urine and soil samples with good results.
Keywords : palladium; platinum; rhodium; 2,4-dihydroxybenzylidenethiorhodanine; high performance liquid chromatography; on-line enrichment.