Isotope Geochemistry
The Center for Isotope Geochemistry (CIG) at Boston College is a state-of-the-art analytical facility specializing in the high-precision measurement of both radiogenic and stable isotopes across a broad array of geological, biological, and environmental materials.
It serves as a collaborative research hub for faculty, students, and external researchers, all working to deepen our understanding of Earth's processes and history, including crust and mantle evolution, paleoenvironmental reconstruction, biogeochemical cycling, and chronostratigraphy. Research conducted at the CIG contributes to both fundamental and applied geoscience, with implications for tectonic processes, paleoclimate studies, geochronology, and environmental change.
The Center emphasizes a collaborative approach to research, wherein users are actively trained in sample preparation, chemical separation, purification, and isotopic analysis under the guidance of Center personnel. Educational engagement is a core value, and motivated undergraduate students are strongly encouraged to participate in ongoing research activities to gain hands-on experience in geochemical techniques. Prospective collaborators and external users are invited to contact the Center鈥檚 management to discuss potential research partnerships and access to facilities.
Director:Diksha Bista
Assistant Director:听Andrew Lonero
Faculty Advisory Committee:
Ethan Baxter (TIMS)
Xingchen听(Tony) Wang (IRMS)
Seth Kruckenberg (SEM)
Capability
The Center for Isotope Geochemistry (CIG) at Boston College offers a comprehensive suite of analytical capabilities for high-precision isotope and trace element analysis across a wide range of materials.
Mineral Separation and Micro-sampling
- Ball mills, magnetic separators
- Heavy liquid separation systems
- Micro-drilling/milling tools for precision sampling of mineral domains
听Imaging and Mineral Characterization
- High-resolution electron microscopy imaging
- EDS, EBSD, and CL analysis for elemental and microstructural characterization
Sample Preparation and Clean Lab Facilities
- Trace-metal clean labs for low-contamination sample prep
- Class 100 laminar flow benches and fume hoods
- Ultra-pure reagents and acid digestion systems
Trace Element and In Situ Analysis
- High-resolution elemental analysis
- In situ laser ablation of solids
- Applicable to minerals, glasses, and metals
Radiogenic Isotope Analysis
- High-precision isotopic analysis (e.g., Nd, Sr, Pb, U, Th)
- Sub-nanogram level sample analysis
- Used in geochronology, tectonics, and crust/mantle evolution studies
Stable Isotope Analysis
- Analysis of light isotopes (e.g., C, N, O)
- Sample types: gases (e.g., N鈧侽, CO鈧�), carbonates, organic matter
- Peripherals: Gas Bench II, Elemental Analyzer (EA)
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Facility Space
The Center for Isotope Geochemistry operates across two primary laboratory spaces located in Devlin Hall and 245 Beacon Street at Boston College.
Devlin Hall laboratory houses a 750 sq. ft. Class 1000 trace-metal clean room constructed to minimize contamination during ultra-trace level chemical processing. These metal-free, HEPA-filtered laboratories are specifically designed for handling sub-nanogram sample quantities. The clean rooms feature 14 Class 100 ULPA-filtered laminar flow benches and hoods, Savillex Teflon distillation units, Analab metal-free hotplates, and precision analytical balances. Environmental control is maintained through consistent temperature regulation and monitored positive pressure, with a Setra Multisense system providing real-time feedback at each lab entrance.
This facility is also home to two IsotopX Phoenix Thermal Ionization Mass Spectrometers (TIMS), installed in 2016 and 2022, respectively. These instruments are optimized for high-precision isotopic analysis of neodymium and strontium in small-sample matrices relevant to Earth and environmental sciences.
A dedicated mineral preparation lab is also located within the Devlin complex, equipped with tools for crushing, grinding, magnetic separation, and micro-milling of geological materials.
The laboratory at 245 Beacon Street supports stable isotope and trace element analysis. It houses four mass spectrometers:
- A Thermo Delta V Plus Isotope Ratio Mass Spectrometer (IRMS) coupled with a Gas Bench II for automated CO鈧� analysis of carbonates and water isotope ratios.
- An Elemental Analyzer (EA) interface for 未鹿鲁C, 未鹿鈦礜, and 未鲁鈦碨 isotopic analysis of solid samples.
- A Thermo 253 Plus IRMS, installed in 2024, configured for high-precision analysis of 未鹿鈦礜 and 未鹿鈦窸 in N鈧侽 using the denitrifier method.
- Agilent 8900 Triple Quadrupole ICP-MS, which can be operated in solution mode or coupled with an Applied Spectra RESOlution 193 nm ArF excimer laser ablation system. This configuration enables high-resolution in situ elemental and isotopic mapping of solid samples, including minerals and glasses.
The laboratory is also equipped with precision drilling devices and a Sartorius microbalance with microgram sensitivity for the accurate preparation and weighing of powdered samples, particularly carbonates.
Instruments
The Center's first TIMS was installed in 2016. It is equipped with nine moveable Faraday collectors, an ion-counting Daly detector, and a full complement of 10鹿鹿 and 10鹿虏 惟 resistors, allowing flexible signal detection across a wide dynamic range. In 2022, a second Phoenix TIMS was commissioned, incorporating the latest ATONA amplifier technology, which provides enhanced stability, lower noise, and improved precision for long-duration measurements. This instrument features the same collector configuration鈥攏ine moveable Faraday cups and an ion-counting Daly detector鈥攅nabling high-precision isotopic analyses even on ultra-low abundance samples.
Both TIMS instruments offer exceptional sensitivity, enabling the acquisition of high-precision isotopic data from sub-nanogram quantities of high-mass elements (e.g., 143Nd/144Nd, 87Sr/86Sr). Long-term external reproducibility routinely achieves better than 15 ppm (2SE), making these systems ideally suited for ultra-low abundance isotopic applications in geochemistry and environmental sciences.
Filament preparation is conducted in-house using an Amada Miyachi spot welder, followed by degassing in a Thermo Fisher DG60 filament outgasser. Sample loading is performed under ULPA-filtered laminar flow conditions at a custom-built filament loading station, ensuring minimal particulate and chemical contamination during handling.
The Thermo 253 Plus IRMS, installed in 2024, is dedicated to high-precision analysis of nitrogen and oxygen isotope ratios in trace quantities of N鈧侽 gas. It is configured exclusively for use with the denitrifier method, a microbiological conversion process that transforms dissolved nitrate into nitrous oxide (N鈧侽) for isotopic analysis.
This instrument is optimized for 未鹿鈦礜 and 未鹿鈦窸 measurements of N鈧侽 in environmental and biogeochemical samples. Its configuration allows for extremely sensitive, low-background analysis of nitrous oxide gas samples.
The Delta V IRMS is a versatile stable isotope instrument equipped with two interchangeable front-end peripherals:
Gas Bench II System: Used for automated, high-throughput analysis of:
- 未鹿鲁C and 未鹿鈦窸 in carbonate minerals
- 未鹿鈦窸 in water samples
- Dissolved inorganic carbon (DIC) content and isotopic composition (未鹿鲁C and 未鹿鈦窸) in water samples
Flash Elemental Analyzer (EA): Used for analysis of solid organic materials, including soils, sediments, biomass, and other organic compounds. It provides:
- Elemental composition (%N, %C, and optionally %S)
- Isotopic ratios (未鹿鈦礜 and 未鹿鲁C) via combustion gas analysis
This dual setup enables flexible workflows for both organic and inorganic stable isotope research.
