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’s management to discuss potential research partnerships and access to facilities.
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Director:Diksha Bista
Assistant Director: Andrew Lonero
Faculty Advisory Committee:
Ethan Baxter (TIMS)
Xingchen (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.
- Ball mills, magnetic separators
- Heavy liquid separation systems
- Micro-drilling/milling tools for precision sampling of mineral domains
- High-resolution electron microscopy imaging
- EDS, EBSD, and CL analysis for elemental and microstructural characterization
- Trace-metal clean labs for low-contamination sample prep
- Class 100 laminar flow benches and fume hoods
- Ultra-pure reagents and acid digestion systems
- High-resolution elemental analysis
- In situ laser ablation of solids
- Applicable to minerals, glasses, and metals
- 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
- Analysis of light isotopes (e.g., C, N, O)
- Sample types: gases (e.g., N₂O, CO₂), carbonates, organic matter
- Peripherals: Gas Bench II, Elemental Analyzer (EA)
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 CO₂ analysis of carbonates and water isotope ratios.
- An Elemental Analyzer (EA) interface for δ¹³C, δ¹⁵N, and δ³⁴S isotopic analysis of solid samples.
- A Thermo 253 Plus IRMS, installed in 2024, configured for high-precision analysis of δ¹⁵N and δ¹⁸O in N₂O 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 10¹¹ and 10¹² Ω 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—nine moveable Faraday cups and an ion-counting Daly detector—enabling 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 N₂O gas. It is configured exclusively for use with the denitrifier method, a microbiological conversion process that transforms dissolved nitrate into nitrous oxide (N₂O) for isotopic analysis.
This instrument is optimized for δ¹⁵N and δ¹⁸O measurements of N₂O 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:
- δ¹³C and δ¹⁸O in carbonate minerals
- δ¹⁸O in water samples
- Dissolved inorganic carbon (DIC) content and isotopic composition (δ¹³C and δ¹⁸O) 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 (δ¹⁵N and δ¹³C) via combustion gas analysis
This dual setup enables flexible workflows for both organic and inorganic stable isotope research.
Installed in 2022, the Agilent 8900 is a high-performance triple quadrupole ICP-MS capable of ultra-trace elemental analysis with excellent interference removal using its collision/reaction cell. It supports two analytical modes:
- Solution Mode: Utilizes a peristaltic pump and a 240-position solution autosampler to measure acid-dissolved solutions or filtered water samples with high throughput and precision.
- Laser Ablation Mode: Operated in tandem with the Applied Spectra RESOlution SE 193 nm ArF excimer laser ablation system, this mode enables high-resolution spatial analysis of solid samples. Applications include trace element mapping in minerals, glasses, biological tissues, and synthetic materials.
This dual capability makes the Agilent 8900 an essential part of the Center’s mission to support cutting-edge, interdisciplinary research.
This excimer laser ablation system is coupled directly to the Agilent 8900 ICP-MS and enables high-resolution trace element analysis of solid samples. It supports both:
- Spot analyses for targeted elemental measurements, and
- 2D elemental mapping for spatially resolved imaging at micrometer scales.
These capabilities are especially useful for geochemical, environmental, and materials science applications that require precise localization of trace elements.
This facility is dedicated to the processing of solid geological samples and the isolation of specific mineral phases. It is equipped with a range of tools for sample preparation, including:
- A Cole-Parmer™ Mixer/Mill™ Single-Clamp High-Energy Ball Mill for grinding rock fragments into fine powders
- Petrographic and binocular microscopes for detailed mineral identification and selection
- An exhausting fume hood designed for safe heavy liquid density separation
- A Frantz isodynamic separator (newly installed) for efficient magnetic mineral separation
- A New Wave MicroMill for high-precision microsampling of specific mineral domains
This lab supports a variety of geochemical and petrological research, from isotopic analyses to trace element studies.
Located in Devlin Hall within the Department of Earth and Environmental Sciences, the SEM facility is a key analytical resource supporting the Center for Isotope Geochemistry. It is equipped with a Tescan Mira 3 Schottky Field Emission SEM, which can operate in both high-vacuum and variable pressure modes.
This versatility enables high-resolution imaging and analysis of a wide range of specimens, including both coated and non-conductive specimens.
This FEG-SEM is equipped with a comprehensive suite of analytical detectors for advanced materials imaging and characterization, including secondary electron (SE), backscatter electron (BSE), and cathodoluminescence (CL) detectors. It also features an integrated Oxford Instruments HKL Symmetry2 Electron Backscatter Diffraction (EBSD) detector and an X-Max 50 Silicon Drift Detector EDS detector. Together, these systems enable the rapid analysis of crystallographic fabrics (i.e., crystallographic preferred orientations), rock microstructures (textural mapping), and the generation of semi-quantitative mineralogical and compositional maps.
Supporting instrumentation for SEM lab includes:
- EMS 150TE turbomolecular-pumped carbon coater – for applying ultra-thin conductive coatings required for SEM, EDS, and EBSD analyses
- Struers LabPol-5 polishing system – for high-quality surface preparation of geological and material samples
- Buehler MiniMet and Vibromet2 polishers – specifically used for precise EBSD sample preparation
- A digital camera-equipped Zeiss Axioskop 40 petrographic microscope and Leica Z6 APO macroscope – for reflected and transmitted light observation and imaging of polished thin sections
- A suite of dedicated workstations – for the post-processing and data analysis.
Center for Isotope Geochemistry
Diksha Bista, PhD
Director, Centre for Isotope Geochemistry
Dr. Diksha Bista joined Boston College in 2025 as the Director of the Centre for Isotope Geochemistry. Prior to this, she worked at the British Geological Survey, where she initially served as the lab manager for the high-precision uranium-lead geochronology laboratory and later as a research scientist within the Stable Isotope Facility. Dr. Bista earned her PhD in isotope geochemistry from the University of Bristol in 2019. She also holds a BSc in Earth and Space Sciences from Constructor University (formerly Jacobs University) in Germany and an MSc in Oceanography from Dalhousie University in Canada.
With extensive hands-on experience operating a range of mass spectrometers, Dr. Bista’s expertise encompasses both radiogenic and stable isotopic systems. Her interest lies in understanding Earth system processes, with a particular focus on the dynamic interactions that shape the planet’s geological and environmental history.
Center for Isotope Geochemistry
Diksha Bista, PhD
Director, Centre for Isotope Geochemistry
diksha.bista@bc.edu
617-552-2785
Devlin Hall 314
Andrew Lonero, M.S.
Assistant Director, Center for Isotope Geochemistry
Andrew Lonero received his B.S. from the University of Hawaii, Hilo and his M.S. from Washington State University. During his graduate research, he worked on the stable isotopes of hydrothermal alterations in volcanic rocks from Yellowstone National Park. His expertise spans stable isotope (CHONS) geochemistry, major and trace-element chemistry (ICP-OES, ICP-MS, XRF) on solid materials and solutions, and method development in mass spectrometry. Before arriving at Boston College as the Assistant Director of the Center for Isotope Geochemistry in 2022, he was the geochemistry lab manager at Utah State University.
Center for Isotope Geochemistry
Andrew Lonero, M.S.
Assistant Director
loneroa@bc.edu
617-552-3711
245 Beacon 004