Comparison of some analytical performance characteristics in inductively coupled plasma spectrometry of platinum group metals and gold

The limits of detection, precision and matrix effects in the inductively co upled plasma spectrometry of platinum group metals (PGMs) and gold were mea sured and evaluated for four ICP-AES and one ICP-MS instrument. The sample matrix was a cationic surfactant used for the PGMs and gold preconcentratio n on a modified silica gel (C18). A sorption of ion associates of PGMs and gold chlorocomplexes with the cation of onium salt N(1-carbaethoxypentadecy l)-trimethyl ammonium bromide was considered. The calibration curves, limit s of detection and matrix effects were evaluated in the presence of 0.003 m ol dm(-3) of onium salt (1.3 mg cm(-3)) and 0.1 mol dm(-3) HCl. The values of limits of detection (3 sigma(bl)) of PGMs for all axial ICP instruments were mostly below 10 ng cm(-3). Lateral observation on dual view ICP instru ment yielded only 3 times higher detection limits in comparison to the axia l mode of the same spectrometer and the detection limits for ICP-MS instrum ent were on the levels of units or tens of pg cm(-3). These limits of detec tion did not significantly differ from values obtained with pure solutions. Matrix effects in the presence of onium salt did not exceed 12% depression in the analytical signals. Besides the coefficients of correlation, the un certainties on centroids of concentrations were calculated for calibration graphs obtained by linear regression. (C) 1999 Elsevier Science B.V. All ri ghts reserved.