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Useful references for Elemental Analyzer samplesHair CompositionBowen G. J., Chesson L., Nielson K., Cerling T. E. and Ehleringer J. R. (2005) Treatment methods for the determination of 2H and 18O of hair keratin by continuous-flow isotope-ratio mass spectrometry. Rapid Communications in Mass Spectrometry, 19, 2371-2378, doi:10.1002/rcm.2069. Water extraction from soilsK. Revesz and P. Wood, A method to extract soil water for stable isotope analysis: Journal of Hydrology, 115 (1990) 397-406. CO reference gas supplierOxygen Service in Orange, California makes CO for regular use with the isotope value in the natural range. Probably, they use sea water as the starting material. The price is just a fraction of other expensive suppliers. We have been using their CO for oxygen isotope reference for years. Dachun Zhang, Lab manager Ag3PO4 SynthesisWe at Menlo Park have also been struggling with d18O standards for use with pyrolysis, especially phosphates. We used two in-house standards at 11.3 and 20 per mil, both secondarily calibrated from VSMOW, but we found we run a lot of samples outside this range - so we custom-made our own standards. I started with two calibrated waters, -16.5 and +253.0 per mil, and mixed them in 5 varying proportions (0.2, 0.4, 0.6, 0.8, 1.0) to make a linear range of waters, measured them for d18O and then added to each a scoop of P2O5. I figured since P2O5 + 3H2O --> 2H3PO4, 3 out of 8 phosphate oxygens should be from the water. I neutralized the samples using NaOH and then did a fast precipitation using AgNO3. Filtered, washed 3X, dried, ground, etc... Results below: d18O water d18O Ag3PO4 Roughly y = 0.45x + 16. Since these weren't exactly what I was looking for I repeated the process using waters of -55 and +30 per mil, and got:
-55.1 -8.6 I performed two calibration runs, including all 5 from the second set and #s 2 and 3 from the first set, and added NBS-18, NBS-19, USGS-34, USGS-35, IAEA-N3, NBS-127, L-SVEC, TU-1, TU-2 (phosphates from Torsten Vennemann), YR1a (low phosphate standard from Ruth Blake), and our in-house High and Low standards. I used our in-house standards for drift and linearity corrections and ran everything else as unknowns (n=4 each). With the exceptions of NBS-18 and 19, which fell slightly below the line, we got an equation (true vs. measured) of y = 0.985x + 0.164, with an R2 of 0.9993. We did notice a slight shift between nitrate standards and phosphate standards. Although they had identical slopes, the phosphate intercept was +0.5 and the nitrate intercept was -0.5. Certainly this deserves a closer look, but it appears that running mixed oxyanions may work for some labs, at least in short runs. Phosphates seem to be quite stable and combust nicely, and the fact that they can easily be customized to fit the isotopic needs of individual labs is a bonus. Our analyses were run on a Eurovector EuroEA (1270C) feeding a VG Optima mass spec, in case anyone is interested... I should also mention we are currently working on a similar method for synthesizing a range of barium sulfate standards. I'll post this method when we have the kinks worked out. Mark Rollog TCEA, Conflo III, and Delta Plus XP Manuals and BrochuresTCEA Operating Manual Addendum |
 NEWS & EVENTSUCSC's Stable Isotope Laboratory operations are back to full operations following the Covid-19 shutdown. Please contact the lab if you are interested in our services. SIL Co-Director Matt McCarthy directed a weekend program for about 20 Educational Opportunity (EOP) STEM transfer students highlighting the use of stable isotope analyses in phyiscial and biological science inquiry. UCSC's Stable Isotope Laboratory welcomes new Ocean Sciences faculty member Pratigya Polissar. Dr. Polissar will join the SIL as a co-director SIL Co-Founder Paul Koch and colleagues review Sundance Film Festival movies for Science magazine. SIL Co-Director Matt McCarthy recieved a NSF Major Research Instrumentation award for new compound specific isotope ratio mass spectrometers. SIL Co-Director Matt McCarthy directed a weekend program for about 40 Educational Opportunity (EOP) STEM transfer students highlighting the use of stable isotope analyses in phyiscial and biological science inquiry. SIL Co-Director Jim Zachos appointed to Ida Benson Lynn Endowed Chair in Ocean Health. UC Santa Cruz biologists Daniel Costa and Luis Huckstadt found valuable samples for comparison of modern Weddell seals to century-old pelts found in the huts of Antarctic explorers Ernest Shackleton and Robert Falcon Scott. Their findings reveal changes in the Ross Sea ecosystem. SIL Co-director Jim Zachos elected to be a member of the National Academy of Sciences! UCSC Stable Isotope Laboratory data used to show threatened grizzly bears in Yellowstone National Park have a vital hankering for a dwindling supply of pine nuts. SIL Co-director and UCSC Physical and Biological Sciences Dean Paul Koch has been elected 2015 AAAS Fellow for "energetic and innovative leadership in applying stable isotope geochemistry to document and interpret environmental change through the past 65 million years of Earth history.". SIL Co-director Jim Zachos has been awarded the 2016 Milutin Milankovic Medal by the European Geosciences Union. Formation of coastal sea ice in North Pacific drives ocean circulation and climate. So indicates evidence published by UCSC scientists Karla Knudson and Christina Ravelo. Christina Ravelo, Professor of Ocean Sciences at UC Santa Cruz and UCSC Stable Isotope Laboratory co-director, has received the 2013-14 Outstanding Faculty Award from the Division of Physical and Biological Sciences. The annual award is the division's highest honor for faculty achievement, recognizing combined excellence in research, teaching, and service. Long-term human influenced dietary habits of Yosemite National Park black bears explored by UCSC scientist Jack Hopkins, Paul Koch, and colleagues. SIL Co-Director Paul Koch honored as a Fellow of the California Academy of Sciences. See story here. Diversity of great white shark diet was shown to be greater than previously thought based on research by UC Santa Cruz colleagues Sora Kim, Paul Koch, and James Estes along with co-author M. Tim Tinker of the U.S. Geological Survey. This work was highlighted in the Los Angeles Times. SIL Co-Director Paul Koch has been named Dean of the UC Santa Cruz Division of Physical and Biological Sciences. Madagascar Lemur extinctions and ecological retreat followed arrival of humans according to UCSC Graduate Student Brooke Crowley, Professor Paul Koch and co-authors. Their findings were recenlty published in the journal Proceedings of the Royal Society B. SIL Co-Director Paul Koch was quoted in the New York Times on research showing that a tiny Paleocene horse Sifrhippus, the first horse, grew even smaller during the Paleocene-Eocene Thermal Maximum climatic warming event. SIL Co-Director Christina Ravelo has been selected as an American Geophysical Union (AGU) Fellow. SIL Co-Directors Paul Koch and Jim Zachos's research on Paleocene-Eocene Thermal Maximum (PETM) climatic warming event is featured in an National Geographic article "Earth Before the Ice" in the October 2011 issue. SIL Co-Director Paul Koch has been appointed Interim Dean of the UC Santa Cruz Division of Physical and Biological Sciences. SIL Co-Director Jim Zachos elected to the American Academy of Arts and Sciences. UCSC's SIL new ThermoScientific MAT 253 isotope ratio mass spectrometer coupled to a Kiel Automated Carbonate Device begins regular operations. UCSC's SIL retires its 15 year-old dual-inlet Optima following a very productive career. The instrument generated over 40,000 data points. Two Tsavo Lions In Famed Killings Get Partial Reprieve according to UCSC Graduate Student Justin Yeakel. Listen to Justin's inteview on National Public Radio's All Things Considered: SIL co-director Christina Ravelo (Ocean Sciences) sails as co-chief scientist on Integrated Ocean Drilling Project (IODP) Expedition 323 to investigate Bearing Sea Paleoceanography.
SIL co-director Christina Ravelo (Ocean Sciences) gives the 2008 Emiliani Lecture at the American Geophysical Union Meeting in San Francisco on "Lessons from the Pliocene Warm Period and the Onset of Northern Hemisphere Glaciation".
UCSC SIL has been funded by the National Science Foundation for a new Dual-Inlet Isotope Ratio Mass Spectrometer with individual acid drip system for very small calcium carbonate samples. SIL co-director Jim Zachos (Earth and Planetary Sciences) recieves prestigious Humbolt Research Award. See Humbolt Award for details. SIL Co-Director Jim Zachos has been selected as an American Geophysical Union (AGU) Fellow. In recognition of the new continuous flow instruments added to the UCSC stable isotope facility a Symposium is being run to highlight the new analytical capabilities. |
