Beyond Vienna: MS/MS Option for the Neoma MC-ICP-MS.

<p>The introduction and rapid adoption of triple quadrupole ICP-MS/MS in the last decade<sup>1</sup> has seen the development of many exciting isotope ratio geoscience applications, including <em>in-situ</em> Rb/Sr dating<sup>2</sup>. By being able to restrict ions of specific mass-to-charge ratios (<em>m/z)</em> only entering the collision/reaction cell, reactive gases such as O<sub>2</sub>, NH<sub>3</sub> and SF<sub>6</sub> can be used to measure ions free of isobaric interferences.  However, many of the isotope ratio applications developed on triple quadrupole ICP-MS/MS would benefit from the excellent isotope ratio precision available from multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). In order to test the feasibility of MC-ICP-MS/MS, Thermo Fisher Scientific™ produced two prototype MC-ICP-MS/MS based on the Thermo Scientific™ Neptune Series™ MC-ICP-MS, named Proteus<sup>3</sup> (in collaboration with the University of Bristol, UK) and Vienna<sup>4</sup>. The Vienna MC-ICP-MS/MS improved on Proteus by introducing a novel pre-cell mass filter and hexapole collision/reaction cell, retaining the sensitivity and predictable mass bias of the Neptune Series MC-ICP-MS. For in-situ Rb/Sr dating both prototype systems reported better than fivefold improvements in precision over triple quadrupole ICP-MS/MS.</p><p>Since the development of the Vienna MC-ICP-MS/MS prototype, Thermo Fisher Scientific has introduced the Thermo Scientific Neoma™ MC-ICP-MS, blending cutting-edge and field proven technology from our Thermo Scientific Ultra™ high resolution IRMS and iCAP Qnova™ ICP-MS<sup>5</sup>. Now with the MS/MS Option, the novel pre-cell mass filter and hexapole collision reaction cell design pioneered in Vienna has been bought to this most modern MC-ICP-MS platform. Any Neoma MC-ICP-MS can now be upgraded to full MS/MS capability, with the resulting MC-ICP-MS/MS having no compromises in sensitivity, accuracy or precision. With the ability to select a discrete range of masses to enter the collision/reaction cell, reactive gases such as O<sub>2</sub>, SF<sub>6 </sub>and NH<sub>3</sub> can be used alongside H<sub>2</sub> and He. Here we demonstrate how the Neoma MC-ICP-MS/MS can be used for a variety of applications, such as Ti, Fe, U and <em>in-situ</em> Rb/Sr dating.</p><p>1.Tanimizu, M.; Sugiyama, N.; Ponzevera, E.; Bayon, G. Determination of Ultra-Low 236U/238U Isotope Ratios by Tandem Quadrupole ICP-MS/MS. <em>J. Anal. At. Spectrom.</em> <strong>2013</strong>, <em>28</em>, 1372–1376.</p><p>2. Zack, T.; Hogmalm, K. J. Laser Ablation Rb/Sr Dating by Online Chemical Separation of Rb and Sr in an Oxygen-Filled Reaction Cell. <em>Chem. Geol.</em> <strong>2016</strong>, <em>437</em>, 120–133.</p><p>3. Bevan, D.; Coath, C. D.; Lewis, J.; Schwieters, J.; Lloyd, N.; Craig, G.; Wehrs, H.; Elliott, T. In Situ Rb–Sr Dating by Collision Cell, Multicollection Inductively-Coupled Plasma Mass-Spectrometry with Pre-Cell Mass-Filter, (CC-MC-ICPMS/MS). <em>J. Anal. At. Spectrom.</em> <strong>2021</strong>, <em>36</em>, 917–931.</p><p>4. Craig, G.; Wehrs, H.; Bevan, D. G.; Pfeifer, M.; Lewis, J.; Coath, C. D.; Elliott, T.; Huang, C.; Lloyd, N. S.; Schwieters, J. B. Project Vienna: A Novel Precell Mass Filter for Collision/Reaction Cell MC-ICPMS/MS. <em>Anal. Chem.</em> <strong>2021</strong>, <em>93</em> (30), 10519–10527.</p><p>5. Brochure: <em>Neoma Multicollector ICP-MS - Illuminating the edge of discovery</em><span> https://assets.thermofisher.com/TFS-Assets/CMD/brochures/br-30600-neoma-mc-icp-ms-br30600-en.pdf</span></p>