Mass Spectrometry Laboratory
The Laboratory
The Mass Spectrometry laboratory is equipped with three mass spectrometers: a Thermo Scientific XSERIES 2 Quad, a Finnigan™ ELEMENT 2, and a Nu Plasma Multicollector with capacity for analysis of liquid samples and in-situ analysis of solid materials by coupling to an ESL NWRFemto Laser Ablation System).
ESL NWRFemto Laser Ablation System is a state-of-the-art laser system that dramatically reduces thermal effects to achieve the most precise analytical data.
LPEG ( by Casey Tackett)
The ELEMENT 2 is a High-Performance, High-Resolution ICP-MS that allows for fairly precise analysis of both isotopes and trace elements.
LPEG (by Casey Tackett)
Thermo Scientific XSERIES2 has dual collectors allowing for a high-resolution analysis of a broad range of trace elements
LPEG (by Casey Tackett)
NU Plasma Multicollector allows for high-resolution analysis of isotopes at a smaller mass range but with much more precision.
LPEG (by Casey Tackett)How it works?
For solution analysis, the sample must be in liquid form. This is archived by dissolving the sample in ultra-pure acids. The sample material is then injected into the inductively coupled plasma (ICP) as an aerosol and transported by argon (carrier gas). Aerosol particles are generated by nebulizing the solution into the hot plasma, the sample is ionized, and the ions are transported to the mass spectrometer, where they are separated according to their mass and energy. This allows the determination of the intensity of individual masses (isotopes).
For solid materials, we use laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS). LA-ICP-MS is a method for in-situ analyses of major, trace element concentrations and isotope ratios in solid materials. A pulsed-focused, high-energy laser beam removes (ablates) material from the sample, and the resulting aerosol is transported into the Inductively Coupled Mass Spectrometer (ICP-MS) for ionization and detection.
Instrumentation and applications:
The Thermo Scientific XSERIES 2 Quad mass spectrometer (MS) has dual collectors, allowing for a high-resolution analysis of a broad range of trace elements. At MCL we use the XSERIES 2 for rapid analysis of trace elements with masses from Li to U. The Finnigan Element 2 is a single collector mass spectrometer (MS) and allows for fairly precise analysis of both isotopes and trace elements. We typically use the Element 2 for U-Pb dating of minerals such as calcite, garnet, hematite, and fluorite. The Nu Plasma Multicollector mass spectrometer (MS) allows for high-resolution analysis of isotopes at a smaller mass range but with much more precision. The Nu Plasma is used for the isotopic characterization of material with elements such as Sr, Fe, and Pb.
Sample types and Preparation:
LA-ICP-MS can analyze almost any type of solid material. In contrast with other techniques, samples do not need to be coated or vacuum-resistant for LA-ICP-MS analysis. However, polishing samples is recommended for more precise results. We typically analyze thin and thick sections as well as epoxy/grain mounts.
For liquid samples, solutions must be dissolved with acid, then introduced via a 0.2 mL/m nebulizer in 2% HNO3.
Calibration and data reduction:
To determine elemental concentration (or isotopic ratios), unknown samples (samples of interest) are bracketed by standards with known elemental and/or isotopic ratios (external standards) and internal standards to account for instrumental drift where applicable. Standards are typically synthetic glasses containing trace elements (e.g., NIST 610, 612, and 614), synthetic glasses from natural rocks (USGS standards), in-house standards (e.g., U-Pb dated specular hematite from Chile), and certified mult-element solution standards.
Data quantification (reduction) is performed using iolite 4.
Contact Jason Kirk (lab manager) at jdkirk@arizona.edu.
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