Multielement analysis of polyethylene using solid sampling electrothermal vaporization ICP mass spectrometry

Next to laser ablation (LA) also electrothermal vaporization (ETV) from a g raphite furnace as a means of sample introduction opens possibilities for d irect analysis of solid samples using inductively coupled plasma mass spect rometry (ICPMS). In this paper, it is demonstrated that solid sampling ETV- ICPMS is very web suited for the determination of metal traces in polyethyl ene. A limited multielement capability is often cited as an important drawb ack of ETV-ICPMS. However, by studying the effect of monitoring an increasi ng number of mass-to-charge ratios on the signal profile (integrated signal intensity and repeatability) of selected analyte elements, the multielemen t capability of (solid sampling) ETV-ICPMS was systematically evaluated, an d the results obtained suggest that,with a quadrupole-based ICPMS instrumen t, at least 11 elements can be determined "simultaneously" (from the same v aporization step), in essence without compromising the sensitivity or the p recision of the results obtained. In this work, the "simultaneous" determin ation of Al, Ba, Cd, Cu, Mn, Pb, and Ti in a polyethylene candidate referen ce material. has been accomplished, despite the large variation in analyte concentration (from 5 ng/g for Mn to 500 mu g/g for Ti) and in furnace beha vior (volatility) they exhibit. To avoid premature losses of Cd during ther mal pretreatment of the samples, Pd was used as a chemical modifier. Two di fferent calibration methods external calibration using an aqueous standard solution and single standard additon-were studied and the results obtained were compared with those obtained using neutron activation analysis (NAA) a nd/or with the corresponding (candidate) certified values (if available). S ingle standard addition was shown to be preferable (average deviation betwe en ICPMS result and reference value < 3%), although-except for Ba-acceptabl e results could also be obtained with external calibration.