The University of Chicago Stable Isotope Ratio facility

Da' Bears

Disclaimer: Do not try this at home. No warranty expressed nor implied. Use at your own risk.

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SEM
instructions
and
Isotopologue scripts
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for more isotopo information, see He, B.; Olack, G.; Colman, A; "Pressure baseline correction and high precision CO₂ clumped-isotope (Δ₄₇) measurements in bellows and micro-volume modes" Rapid Communications in Mass Spectrometry, Volume 26, Issue 24, pages 2837–2853, 30 December 2012
and supporting information too!

Click her for .zip file for SEM, FIB, and EDS instructions and notes

Click here for .zip file with all the Isotopo scripts
(browers like to list or try to run the individual files)

export template to pull out isotopologue data, d47.wke (mV data, need to sort and process to generate ¹³C, ¹⁸O, δ47, etc.)

Isodat .isl script(s) for pressure baseline measurements (makes use of gas definitions: CO2_49 and baseline, but double check the script. Make sure you have them properly defined.)

modified acquistion script, acquisition_gridinfo_export_bellow_mode_BASELINE.isl (...Global/User/DualInlet/ISL);

modified library script, DualInlet_lib_modofied_BH.isl (...Global/ISL/lib);

R-script(s) for data processing (export template used to pull out results for Isodat data files, may need to re-save data in comma delimited file)

setting up batch processing, Clumped_calculation_PBL_correction.R (note changes needed in file structure if running on Windows vs Mac or Linux)

processing script,Clumped_calculation_PBL_correction_do.R (also note you can modify how the baseline is calculated , 47 interpolation or 49 measurement, but make sure you've not hit the limit of -249)

The codes in the R-scripts for Δ₄₇ calculations adapted from the Huntington report Matlab codes:
Methods and limitations of ‘clumped’ CO2 isotope (Δ₄₇) analysis by gas-source isotope ratio mass spectrometry
K. W. Huntington,*, J. M. Eiler, H. P. Affek, W. Guo, M. Bonifacie, L. Y. Yeung, N. Thiagarajan, B. Passey, A. Tripati, M. Daëron, R. Came
Journal of Mass Spectrometry
Volume 44, Issue 9, pages 1318–1329, September 2009
and supporting information too!

The "absolute reference frame" is from the Dennis report:
Defining an absolute reference frame for ‘clumped’ isotope studies of CO₂
Kate J. Dennis, Hagit P. Affek, Benjamin H. Passey, Daniel P. Schrag, John M. Eiler
Geochimica et Cosmochimica Acta
Volume 75, Issue 22, 15 November 2011, Pages 7117–7131

sorry, can't list all the papers ;)

Please contact us if you need more information: golack <at> uchicago.edu