Determination of selenium in serum in the presence of gadolinium with ICP-QQQ-MS

David P. Bishop, Dominic J. Hare, Fred Fryer, Regina V. Taudte, Barbara R. Cardoso, Nerida Cole, Philip A. Doble

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Abstract

Gadolinium (Gd)-based magnetic resonance imaging (MRI) contrasting agents interfere with the determination of selenium (Se) when analysed by single quadrupole inductively coupled plasma-mass spectrometry (ICP-MS). This paper demonstrates that an ICP-triple quadrupole-MS (ICP-QQQ-MS) with oxygen mass shift overcomes Gd++ interference on Se+ and mitigates typically encountered matrix and spectral based interferences. Normal human serum was diluted in a solution containing isopropanol, EDTA, NH4OH and Triton X-100. Samples were unspiked (control) serum; serum spiked with 0.127 μmol L-1 Se or 127 μmol L-1 Gd; and serum spiked with both 0.127 μmol L-1 Se and 127 μmol L-1 Gd. Consideration of collision/reaction gases and conditions for interference mitigation included helium (He); a 'low' and 'high' hydrogen (H2) flow, and oxygen (O2). The instrument tune for O2 was optimised for effective elimination of interferences via a mass shift reaction of Se+ to SeO+. The ICP-QQQ-MS was capable of detecting trace (>9.34 nmol L-1) levels of Se in serum in the presence of Gd in our simulated post-MRI serum sample. The multi-tune capabilities of the ICP-QQQ-MS may be adapted to eliminate other specific isobaric interferences that cause false positive results in other analyses where the analyte is confounded by doubly charged and/or polyatomic species.

Original languageEnglish
Pages (from-to)2842-2846
Number of pages5
JournalAnalyst
Volume140
Issue number8
DOIs
Publication statusPublished - 21 Apr 2015
Externally publishedYes

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