The NCESS geochemistry facility is equipped with a Thermo Scientific iCAP-RQ+ Inductively Coupled Plasma Quadrupole Mass Spectrometer designed for high-sensitivity and low-background elemental and isotopic analyses of geological samples. The instrument provides excellent analytical stability, matrix tolerance, and rapid multi-element capability, making it suitable for trace element determination, solution-based isotopic analysis, and in-situ laser ablation studies when coupled with a laser ablation system. The robust plasma interface, improved ion optics, and dynamic range detection system allow quantitative determination of elements from sub-ppb to high ppm levels with superior precision and accuracy.

The iCAP-RQ+ ICP-MS is equipped with a solid-state, 27 MHz RF generator capable of delivering up to 1600 W of plasma power, ensuring efficient ionization of both refractory and volatile elements. The instrument incorporates a high-performance, two-cone interface (nickel or platinum-tipped sampler and skimmer cones) that minimizes oxide and doubly charged ion formation. The collision/reaction cell employs a kinetic energy discrimination (KED) mode that efficiently removes polyatomic interferences, allowing reliable measurement of critical trace elements in complex matrices.
The ion optics system is optimized for ion transmission stability and long-term reproducibility. The quadrupole mass filter has a unit mass resolution across the entire mass range (2-260 amu) with high scanning speed, enabling rapid data acquisition for multi-element analysis. The dual-mode electron multiplier detector provides a linear dynamic range exceeding nine orders of magnitude, allowing simultaneous measurement of trace and major elements within a single run without detector saturation.

The iCAP-RQ+ is routinely employed for multi-element trace and rare earth element (REE) analyses of geological, environmental, and hydrological samples. The system can be operated in both Standard and He-KED modes for different analytical requirements:

• Standard mode: For high-sensitivity measurement of non-interfered isotopes and major elements.
• KED mode: For interference-free determination of trace elements in matrices with complex polyatomic backgrounds.

The instrument allows measurement of a wide suite of isotopes, including transition metals, high-field strength elements (HFSE), large ion lithophile elements (LILE), and REEs, with excellent reproducibility. Detection limits are typically in the sub-ppb range with precision better than 2% RSD for routine analyses.

Rock powders are digested using HF-HNO₃-HCl acid mixtures in Savillex beakers following standard geochemical protocols. The resulting solutions are dried and re-dissolved in 2% HNO₃ prior to introduction into the ICP-MS. Each analytical batch includes procedural blanks, replicates, and standard reference materials to ensure accuracy and reproducibility. Data acquisition and reduction are performed using Thermo Qtegra Intelligent Scientific Data Solution (ISDS) software, which integrates full instrument control, real-time data monitoring, and post-run evaluation.