ICP-MS-HR spectrometer

General information:

Thermo Element XR mass spectrometer with ICP source, coupled to the New Wave Research UP213 laser, with dual-focusing magnetic sector and mono-collection dedicated to isotopic analysis and/or quantitative (multi-)element analysis in solution or on solid.

Figure 1 : ICP-MS-HR Thermo Element XR (left) and UP213 NWR (right).

Specifications:

• ELEMENT XR: ICP-MS-HR equipped with 3 slots of different widths for a variable mass resolution (R = 300, 4000 and 10000) and with a single-collection detection (SEM electron multiplier in counting pulses mode or analog, and faraday cage depending on the signal amplitude). Linearity of the detector over 12 orders of magnitude, giving a wide range of concentrations from few % to ppq (fg/ml) and precise isotope measurement (relative standard deviation 0.1%) at low resolution.
• UP213: Nd-YAG solid laser, λ = 213nm (deep UV), short pulses (about 4ns), firing rate from 1 to 20Hz providing energy greater than 3 mJ (> 30J/cm²), crater sizes in imaged or focused mode (from 2 to 300 μm).

Principle of operation:

The sample is transformed into an aerosol, which is then transported by a gas flow to a plasma of argon ions (Ar⁺). It occurs through the sample desolvation from the solution, vaporization, dissociation, atomization, and then ionization of the sample in the Ar⁺ ions plasma (subjected to temperature ranging betwwen 6000 to 8000 K). The next steps are extraction, acceleration, deflection and ions separation by the interface and the dual-focusing analyzer, and finally recording by the detector of the number of ions at a given mass/charge ratio.

Uses:

• Quantitative analysis of natural (U, Th) and artificial (Am and Pu) radionuclides at the trace and ultra-trace scale. Isotopic measurement of stable lead in environmental samples (sediments, growth rings of centuries-old trees).
• Systematic analyzes of liquid or solid samples, either natural or from laboratory experiments. The elements of interest are radionuclides, toxic chemicals and radioactive wastes from containment matrices (argillite, cement, glass and steel).

Prohibited use: too concentrated acid solutions (> 5% HNO₃, HCl).

Additional information:

• Constraints for analysis of solutions: standard solutions and samples must be prepared before analysis. Use of mineral acids purified by non-boiling distillation and decontaminated consumables (hot chemical wash and Milli-Q water rinse). Adequate dilution of the sample must be performed for minimizing the matrix effect (dissolved salt contents about 0.1%).
• Constraints for micro-analysis of solids: use of certified solid standard for calibration. Preparation of the solid sample before analysis (pelletizing of powders, coating in epoxy resin of intact samples and polishing). Good flatness of the sample surface.