ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 39, Number 1
JKCSEZ 39(1)
February 20, 1995 

Simultaneous measurements of trace platinum and rhodium, based on catalytic reduction of protons by the adsorbed Pt-formazone and Rh-formaldehyde complexes formed in formaldehyde-hydrazine-sulfuric acid medium, were demonstrated. The conditions for the measurements of Pt and Rh both present at trace levels (>10^-10 M) were 0.004% (w/v) formaldehyde-0.0012% (w/v) hydrazine-0.75 M sulfuric acid. In this medium method detection limits are 7.3×10^-11 M Pt and 3.2×10^-11 M Rh. And dynamic ranges are 5×10^-10~6×10^-8 M and 1×10^-10∼2×10^-8 M for platinum and rhodium respectively. In the linear dynamic ranges, Rh and Ir interfere platinum in the presence of only 10 and 100 times that of Pt respectively. There are no interferences from other platinum group metal ions for rhodium even in the presence of a 500-fold excess of Ir(Ⅳ), a hundredfold excess of platinum.