The University of Chicago
The University of Chicago
The Department of The Geophysical Sciences

Skip to: main navigation" | utility navigation | main content

The University of Chicago Stable Isotope Ratio facility

Resources--see acknowledgements too Research Institutes: 1950-2012
Mass Specs!!! How we measure light stable isotopes
                      V mass spec
Gases:  CO2, N2, CO, H2 and SO2
Isotopes: 13C, 18O, 15N, D/H, 34S
Peripherals: DI, GasbenchII, ConfloIV, EA, TCEA

Gases: CO2, N2, CO, O2
Isotopes: 13C, 18O, 15N
Isotopologues: D47 (CO2), D31 (CO)
Peripherals:  DI, prep on vacuum line

Peripherals!!! How we get samples into the mass specs.
GasBench II
Headspace gas analysis
18O Water: CO2-water equilibration
D/H Water: H2-water equilibration with catalyst
Carbonates: add 105% phosphoric acid
DIC:  add water to vial with 85% phosphoric acid
DOC???  Wet digestion in exetainer vial
Breath:  corn-syrup shots

Costech EA
Costech EA
Burn baby burn
Combusts organic compounds
15N and 13C as N2 and CO2 respectively
amount percent ratios too
periodically run 32S as SO2
Burning tin capsule decomposes inorganics
acid treatment can remove inorganic C

1450 C--Is it hot enough for you?
Really hot carbon reduction
D/H as H2
18O as CO
for 18O off phosphates, sulfates and nitrates
D/H off hydrous minerals
also runs dry organic material
Conflo IV
Conflo openConfloIV-closed
Directs sample He streams form EA or TCEA to mass spec
Automated linearity checks
Potential for auto-dilution on samples (EA only)
Other Toys
Shimadzu GC-FID


Vacuum Line
vacuum line shematic
No, vacuum does not suck

Clean up CO2 for isotopologue work
Convert CO to CO2 and clean it up
Vacuum roasting.
Old school carbonates.

Acknowledgements:  The purchases of the major pieces of equipment, mass spectrometers and peripherals, were supported by NSF award #0923831.  "This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."  And many thanks to the U of C for the needed renovations and added support for the laboratory.