Direct determination of trace cadmium in environmental samples by dynamic reaction cell inductively coupled plasma mass spectrometry

Cadmium is subject to significant Zr and Mo based oxide/hydroxide interferences in ICP-MS analysis of environmental samples. In this work, a dynamic reaction cell (DRC) technology was used to eliminate these metal oxide/hydroxide interferences. The potentially interfering ions (94)zr(16)OH(+), (MoOH+)-Mo-94-O-16 and (MoO+)-Mo-95-O-16 on Cd-111(+) were oxidized to higher oxides (ZrO2H+)-Zr-94/(ZrO3H+)-Zr-94, (MoO2H+)-Mo-94/(MoO3H+)-Mo-94, and (MoO2+)-Mo-95/(MoO3+)-Mo-95 by O-2 as the reaction gas in DRC. Under the optimized O-2 flow rate (2.0 mL min(-1)) and DRC rejection parameter q (Rpq, 0.75). the background signal was reduced by up to 100-fold at m/z 111 and the limit of quantitation (LOQ 10 sigma) of 0.1 ng g(-1) was obtained The proposed method was applied to direct analysis of trace Cd in a series of soil and sediment standard reference materials and the satisfactory results showed that it has great potential for the direct determination of trace or ultra-trace levels of cadmium in environmental samples (C) 2010 Elsevier Ltd. All rights reserved.