LA ICP MS WITH NEOMA AND RESOlution ASI 193 nm EXCIMER LASER

The Neoma ICP-MS is a state-of-the-art inductively coupled plasma mass spectrometer designed for high-precision isotopic and elemental analysis across various scientific fields, including geochemistry, environmental science, and materials research. It is equipped with advanced features such as a high-sensitivity ion lens system and cutting-edge detector technology, enabling the accurate measurement of isotopic ratios and trace elements, even at extremely low concentrations. The Neoma’s flexibility makes it ideal for coupling with laser ablation systems (LA-ICP-MS), facilitating in situ analysis of solid samples with exceptional spatial resolution. Its robust design and user-friendly software streamline complex workflows, allowing researchers to achieve reliable data with high throughput, making it a valuable tool for studies requiring precise geochemical fingerprinting, isotope dating, and trace element analysis.

The Neoma ICP-MS, in our laboratory, is coupled with a RESOlution ASI 193 nm excimer laser ablation system, creating a powerful platform for high-precision isotopic and elemental analysis. This combination allows for in situ analysis of solid samples with excellent spatial resolution and sensitivity, making it ideal for studying a wide range of geological and environmental materials. The RESOlution 193 nm laser provides precise ablation, generating fine aerosols that are efficiently introduced into the Neoma ICP-MS, ensuring accurate measurement of isotopic ratios and trace elements. This setup enables detailed geochemical fingerprinting, isotope dating, and trace element profiling, delivering robust and reliable data for a variety of research applications.

Key Components:

Laser Ablation System:

• A laser ablation system is used to vaporize a tiny portion of the mineral sample, creating an aerosol that is transported into the ICP-MS.
• The laser, a 193 nm ArF excimer, is focused on the mineral surface to produce fine ablation pits, often in the range of 10-40 micrometers in diameter.
• Spot size, laser fluence, and repetition rate are adjustable to optimize the ablation for different minerals, considering their hardness and matrix effects.

Key Components of the ICP-MS :

1. Hexapole Collision/Reaction Cell:
   • Utilizes robust Thermo Scientific iCAP™ TQ ICP-MS technology.
   • Can operate with up to four reaction gases (e.g., O₂, NH₃, H₂, He).
   • Allows for the suppression of argon species, crucial for reducing interferences and improving the accuracy of isotope measurements.
   • Facilitates the removal of unwanted molecular interferences, enhancing the precision of the isotopic data.
2. Electrostatic Analyzer (ESA):
   • Works in conjunction with the magnetic sector to separate ions based on their kinetic energy.
   • Ensures that only ions with specific energy levels reach the detector, improving the resolution and accuracy of the measurements.
3. Magnetic Sector:
   • Water-cooled and laminated for better thermal stability, ensuring consistent performance during prolonged use.
   • Offers fast settling times, which is beneficial for achieving high throughput and rapid analysis of multiple samples.
   • Separates ions based on their mass-to-charge ratio, enabling precise isotopic differentiation.
4. Reproducible Resolution Switching:
   • Provides flexibility to adjust the resolution of the instrument, allowing users to optimize for different elements or isotopes as needed.
   • This feature ensures that both high-precision measurements and routine analyses can be performed without compromising the quality of the data.
5. XHR (Extra High Resolution) (Optional):
   • The extra-high resolution mode is designed to resolve hydride interferences, a common issue in isotopic measurements of certain elements.
   • It significantly improves the accuracy of the isotopic data by separating closely spaced ion signals that may otherwise overlap.
6. Unique Pre-Cell Mass Filter:
   • Allows for the removal of matrix elements before entering the reaction cell.
   • This is crucial for reducing matrix effects that can affect the sensitivity and accuracy of isotope ratio measurements, particularly in complex samples like geological materials.

Applications in Geochemistry and Isotope Studies:

The Neoma MS/MS MC-ICP-MS is well-suited for high-precision isotopic analyses, including U-Pb dating, Sr, Nd, and Hf isotopic studies, and trace element analysis. It is particularly valuable in geochronology, where resolving small isotopic variations is essential for dating geological events with high accuracy. The use of reaction gases and the hexapole collision cell allows for the removal of interferences, making it ideal for measuring isotopic ratios in complex matrices like rocks, minerals, and even biological samples.

Analytical Workflow

The analytical workflow and components of the Neoma MS/MS MC-ICP-MS system provided enhanced capabilities in filtering, reacting, and separating ions for high-precision isotopic analysis. Here’s an explanation of the key features illustrated:

Analytical Workflow:

1. Filter: Pre-cell Mass Filter MS:
   • The pre-cell mass filter removes unwanted elements like O, Ag, Cd, Ar before they enter the collision/reaction cell.
   • This step is critical for eliminating non-isobaric interferences from the sample matrix, ensuring that the analyte’s mass spectrum remains clean.
   • By using this filter, the system enhances the accuracy of subsequent isotopic measurements, especially for samples with complex matrices.
2. React: Hexapole Collision/Reaction Cell:
   • This cell is equipped with the capability to introduce up to four different reactive gases (e.g., O₂, NH₃, H₂, He).
   • The collision/reaction cell can modify the analyte ions through reactions that remove isobaric interferences, allowing for a more precise separation of isotopic signals.
   • This process is especially useful in geochemistry, where resolving interferences such as Rb from Sr is crucial for accurate isotopic ratio measurements (e.g., ⁸⁷Sr/⁸⁶Sr).
3. Separate: Magnetic Sector for Isotope Separation:
   • Following the reaction cell, ions pass through a magnetic sector, which separates them based on their mass-to-charge ratio (m/z).
   • This sector is water-cooled and laminated, providing thermal stability that enhances the reproducibility of the measurements.
   • The system can achieve fast settling times, enabling peak jumping between different isotopic systems. This is particularly advantageous when analyzing multiple isotopes in a single run, optimizing sample usage.

Additional Features:

• The variable multicollector detector array with 11 Faraday cup detectors allows for simultaneous measurement of various isotopes, ensuring high precision and throughput. This feature is critical when measuring isotopic systems like Rb-Sr or U-Pb, as it enables concurrent analysis of multiple isotopes, thus reducing analysis time.
• The moveable collector array adds flexibility, making it possible to cover a wide range of isotopic applications, from light elements like Li to heavy elements like U, in either low or high-resolution modes.

Applications in Isotopic Research:

The Neoma MS/MS MC-ICP-MS is designed to tackle complex isotopic analyses where precision and interference removal are critical. Its technology is particularly valuable for:

• Geochronology: Precise dating of rocks and minerals using systems like Rb-Sr, U-Pb, and Lu-Hf.
• Environmental Studies: Tracking contaminants and sources through isotopic fingerprints.
• Geochemistry: Characterizing trace element compositions and isotopic ratios in geological samples, including the analysis of isotopic variations in mantle-derived or crustal-derived materials.

This system’s ability to filter out matrix interferences, react selectively with unwanted ions, and separate isotopes efficiently makes it an advanced tool for cutting-edge research in isotope geochemistry. It supports the development of new methodologies for analyzing Sr isotopes, as well as trace elements, enhancing the precision and reliability of geochemical studies.