If you’re in Winnipeg and love isotopes, then please come to Dr. Brett Walker’s presentation at 12:10 pm in room 223 of the Wallace Building at the University of Manitoba. It’s all part of the fun at this year’s Advances in Stable Isotope Techniques and Applications (ASITA) Conference.
Brett D. Walker, Steven R. Beaupré, Sheila Griffin, Jennifer Walker, Ellen Druffel, Xiaomei Xu. (2019) A Novel Sealed-tube Method for δ13C Analysis of CO2 via a Gas Bench II Continuous Flow IRMS at UC Irvine. Advances in Stable Isotope Techniques and Applications (ASITA) Conference. Winnipeg, Manitoba, Canda.
Abstract: The oxidation of environmental samples to CO2 and subsequent isotopic analysis on a Gas Bench II continuous-flow isotope ratio mass spectrometer (IRMS) can present many analytical challenges. In off-line applications, such as UV photochemical oxidation of aqueous DOC, only 1 sample is prepared per day. Therefore, long-term storage (months-years) of equilibrated sample CO2 splits is desirable, in order to accumulate a sufficient number of samples to warrant a day of isotopic measurements. Here we present our sealed-tube sample preparation technique for the measurements of CO2 via a Gas Bench II IRMS at UC Irvine. We also present several years of IAEA and UC Irvine isotope standards showing the robustness of this method for accurate δ13C isotope analysis of small sample gas splits (10-35 μgC). We also discuss the evolution of the technique and several pitfalls to avoid during its implementation to minimize sample loss (<1% failure rate) and to maximize efficiency and measurement precision (less than ±0.1‰). This technique is an alternative method for δ13C analyses of samples of samples where off-line isolation isolation and long-term storage are desired, but also higher sample throughput than a traditional dual-inlet cracker setup.