Noble metal modifiers for antimony determination by graphite furnace atomic absorption spectrometry in biological samples

The use of palladium, iridium or rhodium as a modifier in graphite furnace atomic absorption spectrometry was investigated for the determination of an timony in eluent fractions from high-performance liquid chromatography sepa ration of clinical samples. The separation of albumin and transferrin at th e physiological pH was carried out by ion chromatography on a Cosmogel DEAE column. As an eluent, 0.01 mol l(-1) Tris-HCl in NaCl 1 mol l(-1) gradient was used. Several fractions-of 0.5 mi each were collected and the concentr ation of antimony was determined off-line by GFAAS. Palladium, iridium and rhodium effectively stabilise antimony in an aqueous standard solution. In the presence of proteins, Tris-HCl buffer and NaCl, rhodium loses its stabi lising performance. However, palladium and iridium were found to be efficie nt with respect to stabilisation of antimony up to 1500 degreesC in matrix- containing solutions.