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 (H2) is one of the most effective and frequently used reaction/collision gases. However, the H2 reaction produces interference in the detection of selenium (Se) in bromine (Br)-containing samples, such as extracellular fluids. In this study, deuterium (D2) was evaluated for possible use as a reaction gas instead of H2. Although Se concentration in serum and urine was over-estimated in the H2 reaction mode, it was determined accurately in the D2 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 H2 or the D2 reaction. The 79Br1H+ and 81Br1H+ interferences appearing at m/z 80 and 82, respectively, were decreased by changing from the H2 reaction mode to the D2 one. Thus, D2 was effective in dissociating polyatomic interferences and removing Br interferences during Se determination and speciation, suggesting that the D2 reaction mode is useful for selenometallomics, particularly in samples containing Br, such as serum, urine and cell culture medium.