Earth Systems Stable Isotope Laboratory

Philosophy of open data with transparent and reproducible research 

We believe in being open about how we have collected and reduced data from your samples. All of our data reduction is done in R Markdown files, allowing for full documentation of our QA/QC and the math used to determine isotope ratios. Example: https://isoprocessor.isoverse.org/articles/ea_irms_example_carbon.html. This is aided by the use of Isoreader and Isoprocessor (https://www.isoverse.org/). Your final product will include not only isotope values, but also full documentation of their production, and all original mass spec data files. 

Philosophy of an open, teaching lab 

Facilities like these provide the maximum benefit to users when they have in-person access and training to all aspects of sample preparation and analysis. For this reason, we encourage users, particularly those based at CU (who have easy access to the facility) to get trained in sample preparation and analysis. This provides the best integration of the user's knowledge of their samples and research goals with the analytical side of the work. This kind of training and experience, while time-intensive for researchers, provides a wide range of skills in analytical techniques, instrument troubleshooting, data analysis and coding skills, and thorough data interpretation that open doors for jobs both inside and outside of academics. We understand that this is not an option for all researchers, so we also are happy to offer the opportunity to shadow our facility staff as they prepare and analyze your samples and reduce the data. This is a great option for a student to at least see and understand the steps involved in creating their data in a way that is still efficient for our lab staff.  

While we encourage graduate and undergraduate researchers who are willing and have the time to invest in this training, we can no longer allow undergrad lab assistants connected with other labs (at CU or beyond) to act as the labor for external users. This is due to a combination of factors, including maintaining safety within the lab, needing to minimize undue wear and tear on equipment and lab materials, and time constraints for the lab staff. We emphasize that this DOES NOT include undergraduates who are analyzing samples for their own research projects; we do welcome and encourage undergraduate researchers to come and learn in our facility. If you have questions about what the policy entails, please reach out! 

Instrumentation Details

Method Development 

We run a research laboratory and are always interested in increasing our analytical capabilities and engaging in interesting problems. Please contact Ashley Maloney (Delta IRMS), Katie Snell (Clumped DI 253) or Sebastian Kopf (CF 253) if you have isotope measurement needs that are not listed on the website.

Gas source, dual-inlet stable isotope ratio MS

The Thermo 253+ dual inlet mass spectrometer is specially designed to measure different masses of carbon dioxide at very high precision. This measurement provides carbon, oxygen and “clumped” isotope ratios for carbonate minerals, which enables us to reconstruct the temperature at which the carbonate formed, along with information about carbon cycle changes and hydrologic changes, all for the same sample. This provides a very powerful suite of data regarding ancient climate and environment, from minerals that are ubiquitous in the rock record. It can also provide useful constraint on burial histories of carbonate rocks, and thus utility to industry applications. This particular instrument was the first of its kind in the US, with modifications from previous models that allow us to measure smaller samples than previously possible. 

• High-precision measurement of small abundance isotopologues
• Primary application: mass-47 of CO₂ for determining ancient temperatures of carbonate mineral formation
• Applications for paleoclimate, tectonics, subsurface fluid flow

Gas source, gas chromatography isotope ratio MS

The second Thermo 253+ isotope ratio mass spectrometer in the CUBES SIL is configured for continuous flow mode and equipped with a gas chromatography online combustion/pyrolysis interface that allows for compound-specific carbon and hydrogen isotope measurements. This instrument is optimized for the isotopic characterization of mixtures of organic molecules at trace quantities (~10ng per compound for carbon, ~100ng per compound for hydrogen) which provides powerful information for paloeclimate research, forensic analysis, ecological isotope tracing, oil & gas prospecting and many other organic chemistry applications. 

• GC combusion: compound-specific δ13C and δ15N of organic molecules
• GC pyrolysis: compound-specific δD of organic molecules

Gas source, continuous flow stable isotope ratio MS

The Thermo Delta V and its peripherals enable measurement of C,H,N,O and S via headspace sampling, on-line combustion and high temperature conversion elemental analysis, coupled with continuous flow stable isotope analysis. This “workhouse” mass spectrometer can measure stable isotopes of purified organic tissues such as collagen, hair, plants and microbes, as well as organic matter preserved in soils and sediments, carbonate minerals and waters, to name a few. Applications span diverse research fields from agriculture to anthropology and this instrument is widely used in the department and across campus. 

• Elemental Analyzer:  wgt % C, N, δ13C & δ15N of organic matterer in sediments, soil, plants and animals; both natural and labeled abundances
• Headspace Analyzer: Carbonate δ13C & δ18O; Waters – δ13C of DIC; δ15N & δ18O of nitrates/nitrites
• High-temperature conversion EA: δ18O & δD of bone, fossils, methane and hydrogen gas, & bulk organic matter, volcanic glass

Rates for Analytical Services: Rates posted below are for CU users; we also provide services for external (non-CU) users; contact us for those rates (a few dollars higher than internal rates). Additional charges may be incurred for rush and/or small orders and if necessary to cover user messes in the lab.  

Rates for "typical" EA user (base rate + mass spec + data reduction) 

• EA pure organic samples $10  
• EA difficult samples (sediment/soil, filter, enriched) $12  
  + prep and/or weighing $5–$21 

Rates for "typical" GB carbonate user (base rate + mass spec + data reduction) 

• GB carbonate $15  
  + weighing $5/sample 
• GB DIC $20  
  + weighing DIC standards $150 flat fee 

Rates for "typical" TCEA user (base rate + mass spec + data reduction) 

• TCEA O or H organics $23 
• TCEA H and O organics $25  
• TCEA H volcanic glass $23 
  + weighing $5/sample