Effects of deuterium in octopole reaction and collision cell ICP-MS on detection of selenium in extracellular fluids

Inductively coupled plasma-mass spectrometry (ICP-MS) equipped with a reaction/collision cell has been successfully used for dissociating polyatomic interferences. Hydrogen (H-2) is one of the most effective and frequently used reaction/collision gases. However, the H-2 reaction produces interference in the detection of selenium (Se) in bromine (Br)-containing samples, such as extracellular fluids. In this study, deuterium (D-2) was evaluated for possible use as a reaction gas instead of H-2. Although Se concentration in serum and urine was over-estimated in the H-2 reaction mode, it was determined accurately in the D-2 one. In speciation analyses, the background counts at m/z 77, 78 and 80 were reduced and the signal-to-noise (S/N) ratios were improved by either the H-2 or the D-2 reaction. The (BrH+)-Br-79-H-1 and (BrH+)-Br-81-H-1 interferences appearing at m/z 80 and 82, respectively, were decreased by changing from the H, reaction mode to the D-2 one. Thus, D-2 was effective in dissociating polyatomic interferences and removing Br interferences during Se determination and speciation, suggesting that the D-2 reaction mode is useful for selenometallomics, particularly in samples containing Br, such as serum, urine and cell culture medium. (c) 2005 Elsevier B.V. All rights reserved.