# Resources

This is where I post all the other useful stuff that doesn't seem to fit anywhere else. Click on the arrow next to each topic to see a description and the linked file.

### Excel Calculators

*An Excel spreadsheet that will calculate a blank-corrected delta value, and the uncertainty in that value due to uncertainties in measurements of both sample and blank. Based on the equations outlined by John Hayes in his Practice and Principles manuscript.* Blank Correction

*Similar to "Background Correction" above, this is an excel spreadsheet that will calculate mixing in a 2-component system where the isotope ratios of each endmember are known. It also calculates the uncertainty in the mixing fraction, which is its real value. Based on the equations outlined by John Hayes in his Practice and Principles manuscript.* Isotope Mixing

*A common chore in my lab is mixing D2O and H2O to produce water of a specified isotopic composition. This Excel spreadsheet does the calculations for you.* Water isotope mixing

*A simple table of the molecular masses of n-alkanes, ketones, alcohols, and fatty acids with varying chain lengths. A second table lists the stable isotope pattern expected for different numbers of carbon atoms. Nothing fancy, but I find it useful.* Molecular Ions

### Articles

An applications note that my students Elliott Mueller and Juli Panehall wrote for Thermo about the measurement of carbon and hydrogen isotopes in acetate via Orbitrap mass spectrometry.Orbitrap acetate

*My Ph.D. thesis from Indiana University. Most of this material has appeared in five published research articles. Chapters 4 and 5 contain some additional data on hydrogen exchange and sulfate-reducing bacteria, respectively.* Sessions thesis

*Chapter prepared for a short course sponsored by the Mineralogical Society of America and organized by John W. Valley and David R. Cole, and one of the better summaries I know of how isotopes behave in metabolic reaction networks. We called this chapter "War and Peace" when I was a graduate student, and he made us edit it for him.* JMH War and Peace

*Originally published in 1983, I think this is one of the best introductions to the usage of stable isotopes in biogeochemistry. It was updated in 2002 by JMH to include sections on primary standards of stable isotopic abundance, statistical limits on the determination of isotopic ratios, and uncertainties associated with blank-corrected isotope ratios, and then I wrangled it into a new-fangled PDF format for him.* JMH Practice and Principles

*A practical description of calculations using isotopes that are relevant to biogeochemical systems. Especially useful for its evaluation of systematic errors that arise from common approximate forms of calculations involving mass balance and Rayleigh distillation.* Isotopic Calculations

*The definitive guideline for nomenclature and definitions related to stable isotopes. Published in Rapid Communications in Mass Spectrometry, vol 25. The definition of a delta value does not include a factor of 1000...!* Isotope Nomenclature