Selective determination of palladium by on-line column preconcentration and graphite furnace atomic absorption spectrometry

The present work describes a fully automated on-line column separation and preconcentration system for the determination of trace and ultratrace levels of palladium by graphite furnace atomic absorption spectrometry (GFAAS). Palladium is preconcentrated in a microcolumn which has been reversibly loaded with the selective complexing agent N,N-diethyl-N′-benzoylthiourea (DEBT). The palladium complex is eluted with 60 μl of ethanol and directly introduced into the graphite furnace. Sensitivity enhancements of 40, 70 and 200 can be obtained from sample volumes of 0.80, 1.86 and 4.85 ml, respectively. The corresponding detection limits are 51, 25 and 13 ng l−1, calculated by the calibration graph method (N=10, P=95%). In 6.5% (vv) nitric acid solutions, alkaline, alkaline-earth and base metal ions such as Cu(II), Fe(III), Co(II) and Ni(II) etc. as well as precious metals are tolerated up to concentrations of 10 g l−1 and more. The relative standard deviations of the linear calibration graphs are 1.7-2.9% (N=10, P=95%).