Coprecipitation of gold(III), palladium(II) and lead(II) for their flame atomic absorption spectrometric determinations.

An enrichment-separation procedure based on the coprecipitation of gold(III), palladium(II) and lead(II) ions with nickel(II)-5-methyl-4-(2-thiazolylazo) resorcinol complex has been developed. The analytical parameters including pH, amounts of 5-methyl-4-(2-thiazolylazo) resorcinol, sample volume, etc. was investigated for quantitative recoveries of Au(III), Pd(II) and Pb(II). Interference due to various cations and anions has also been investigated. The detection limits for analyte ions by 3sigma were 2.6 microg L(-1) for lead, 1.5 microg L(-1) for gold, 2.1 microg L(-1) for palladium. The accuracy of the method was evaluated by the analysis of certified reference materials (NIST SRM 2711 Montana soil, GBW 07309 Stream sediment). The proposed procedure was successfully applied to environmental samples for the determinations of analytes.