SIMULTANEOUS COPRECIPITATION OF PD(II), RH(III) AND AU(III) WITH MN(OH)2 WITHOUT CHELATING AGENT PRIOR TO FLAME ATOMIC ABSORPTION SPECTROMETRY DETERMINATION

a separation-preconcentration procedure was developed for determination of trace amounts of palladium, rhodium and gold in dust and water samples by flame atomic absorption spectrometry after simultaneous coprecipitation by mn(oh)2 without chelating agent. the precipitate could be easily dissolved with concentrated nitric acid. the influence of the various analytical parameters such as ph, sample volume, centrifuge time, standing time, centrifugation rate and time, amounts of manganese and matrix effects were studied for the quantitative recoveries of the analyte ions. under the optimized experimental conditions, the calibration curves for pd(ii), rh(iii) and au(iii) were linear from 8.0 to 2000.0, 1.0 to 750.0 and 5.0 to 1000.0 ng ml-1, respectively. the relative standard deviations for seven replicate determinations of a mixture of 0.1 mg ml-1 palladium, rhodium and gold in the original solution were 2.1, 1.9 and 2.4%, respectively. the detection limits based on 3sb for pd(ii), rh(iii) and au(iii) in the original solution were 2.2, 0.3 and 1.3 ng ml-1, respectively. the proposed method has been applied for determination of trace amounts of palladium, rhodium and gold ions in the standard, road dust and water samples and satisfactory results were obtained.