The UC Irvine Center for Isotope Tracers in Earth Science (CITIES) facility in the School of Physical Sciences houses a range of sophisticated analytical instrumentation. This includes four stable isotope mass spectrometers (IRMS), capable of measuring air, water, soil, plant, and rock samples, and a new High-Resolution Inductively Coupled Plasma Mass Spectrometer (HR-ICP-MS) that is utilized for measuring elemental and isotopic tracers in natural samples.
The HR-ICP-MS ( Nu Instruments AttoM) was acquired in 2009 with an NSF Major Research Instrumentation grant to Kathleen Johnson (co-PIs Saltzman and Trumbore) and matching funds from the School of Physical Sciences. The AttoM can be utilized for high-precision analysis of nearly every element in the periodic table in both inorganic and organic solution matrices for a wide range of applications. ICP-MS is the most flexible analytical technique for elemental analysis and has become the preferred tool for research as well as routine analyses in a wide variety of areas. It is a fast, multi-elemental technique that offers significant advantages over other elemental analysis techniques, such as ICP-AES and GF-AAS, including lower detection limits, higher sample throughput, the ability to handle both simple and complex matrices, and the ability to measure isotope ratios.
As compared with quadrupole ICP-MS instruments, HR-ICP-MS instruments utilize both a magnetic sector and an electrostatic sector to separate and focus the ion beams. The primary advantages of high-resolution (or “sector-field”) ICP-MS instruments include:
- High mass resolution which allows clear separation of analytes from spectral interferences.
- High sensitivity, high signal-to-noise ratios and high ion transmission stability allow for better detection limits and more accurate results for elemental concentrations and isotope ratios.
- A high dynamic range (1012) and very fast scan speed that enables quantitative measurement of both ultra-trace and major elements in a single analysis, which in turn results in high sample throughput.
- Flat top peak shapes allow for isotope ratio measurements and more precise element ratios compared to quadrupole instruments.
The Nu AttoM incorporates unique “FastScan Ion Optics” which allow for extremely fast scanning over a mass range of up to 40% of a given mass with no added mass discrimination effects. The acceleration energy and electrostatic analyzer (ESA) voltages remain constant, therefore inducing no mass bias effects. This scanning can be done almost instantaneously (< 20 μs), therefore reducing the effects of signal instability and allowing extremely fast peak jumping for precise isotope ratio analysis or elemental analysis on a small mass region. In addition, this feature can be used together with the magnetic scanning to increase integration times over the whole mass range. In short, the FastScan Ion Optics allow for fast multi-elemental analyses with scan times and precisions that rival quadrupole instruments and precise isotope ratio measurements at all available resolutions.
The Nu AttoM HR-ICP-MS is available for use by researchers from other laboratories, universities, and non-profits. For more information, please contact Kathleen Johnson.