Jahrestagung der Arbeitsgemeinschaft
Stabile Isotope e.V.
26.–29. September 2021 | TU Darmstadt
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Block 1.2: Analytik, Methoden, Technik und Qualitätssicherung stabiler Isotope
16:00 - 16:15
Comprehensive Isotope Ratio MS of Oxyanions with an Electrospray-Orbitrap
1Thermo Fisher Scientific, Deutschland; 2University of Colorado, Boulder, USA
A new, comprehensive approach for IRMS using an electrospray ionization (ESI) Orbitrap gives access to multidimensional isotope signatures of intact polar compounds in liquid samples.
Customized sample introduction and automation, applying IRMS specific rules, were developed by using nitrate as a model compound. In total, 7 isotopologs of nitrate can be quantified simultaneously opening multiple pathways for calculating δ15Ν, δ18O, δ17O and Δ17O values with sub-‰ precision and accuracy. It also offers a unique way to measure nonrandom isotopic distributions (“clumping”) in oxyanions.
The approach can be applied to other oxyanions like nitrite and sulfate. First results will also be shown.
This study bridges the gap between bioanalytical MS and IRMS providing methods to measure new isotopic signatures in intact organic and inorganic compounds.
16:15 - 16:30
The next leap forward in gas IRMS
Thermo Fisher Scientific, Deutschland
Thermo Scientific™ Qtegra™ Intelligent Scientific Data Solution (ISDS) Software is carefully optimized to revolutionize your gas IRMS analyses, delivering simplicity, efficiency and quality in your laboratory. Built to cater to the most diverse applications, Qtegra ISDS Software provides you with the level of control that you require, within a logical, easy-to-use framework, enabling you to dramatically improve your productivity. Join us for a software tour.
To compliment the arrival of Qtegra ISDS Software, we are launching the next generation of Thermo Scientific™ DELTA Series IRMS – the Thermo Scientific™ DELTA Q™ IRMS. DELTA Q IRMS is the world’s first net zero mass spectrometer launched as a part of the IsoFootprint project, a new initiative by the Inorganic Mass Spectrometry team with the aim to set the pathway towards true net zero. All the CO2 emitted to the atmosphere during the manufacture of the instrument (from extraction of the raw materials to transport and assembly) will be removed from the atmosphere through investment in carbon dioxide removal projects. Projects were selected with priority given to those that were permanent, additional, globally sustainable and supporting nascent technology that has the ability to scale
Join us to learn more about sustainable isotope analysis driven by Qtegra ISDS Software. The journey has begun.
16:30 - 16:45
Improved throughput for δ18O and δD measurements of water with Cavity Ring-Down Spectroscopy
1Picarro B.V., Niederlande; 2Picarro Inc., USA
Oxygen (18O/16O) and deuterium (D/H) isotopes are a widespread tool to trace physical and chemical processes in hydrology and biogeosciences. Precision and throughput are key parameters for water isotope analysis. Here, we will present two new methodologies for the Picarro L2130-i Cavity Ring-Down Spectroscopy (CRDS) water isotope analyzer that allow the user to increase the throughput without compromising data quality.
The Picarro Express Method now distinguishes between a memory reduction stage and a sample analysis stage and allows the user to measure up to 50 samples per day while maintaining the excellent precision of CRDS (i.e., 0.01‰ for δ18O and 0.05‰ for δD). This corresponds to doubling the throughput compared to the standard Picarro methodology. The Picarro Survey Method makes use of ultrafast injections and sorts the samples by their measured isotopic values, enabling a powerful new strategy to reduce memory effects.
We present these different measurement strategies that increase the throughput for routine water isotope analysis. The improved methodologies use software based modifications of the injection procedure, and do not require any hardware changes.
16:45 - 17:00
A new infiltration optimized tracer application method for 15N and 18O tracers in field soil experiments
1Institut für Grünland und Futterbauwissenschaften, Agrar- und Umweltwissenschaftliche Fakultät, Universität Rostock, 18059 Rostock; 2Soil and Physical Sciences Department, Faculty of Agriculture and Life Sciences, Lincoln University, PO Box 84, Lincoln, 7647, New Zealand
Nitrous Oxide is a long-lived greenhouse gas with the third most important contribution to radiative forcing the dominant anthropogenic ozone-depleting substance emitted. There are many important pathways from agricultural soils for N2O production besides nitrification and denitrification that are challenging to distinguish. Isotopic tracer methods are applied to aid differentiating between microbial and chemical sources. Commonly used application schemes apply 15N-NH4NO3 (triple labeling method) or additionally 18O-H2O and 18O-NO3 (dual isotope method). Both methods assume a homogenous distribution of the tracers within the examined soil volume. Field experiments can further improve our understanding as they incorporate undisturbed soils with intact soil aggregates and plant effects. Preferential flow represents the biggest obstacle for a homogeneous, fast and large area application of tracer. This effects application methods used for field experiments like by watering can or with sprinklers as they promote ponding. Better infiltration patterns visualized by blue dye solution were achieved by slowing down application speed and promoting infiltration by capillary forces. For a 15N comparative study in grassland, drip irrigation was chosen as it is scalable and a noninvasive method. Application by drip irrigation resulted in a smaller standard deviation of the 15N concentrations and a larger recovery rate compared to application by sprinkler. After successful pretest, application by drip irrigation was implemented for the central experiment in Gießen of the DASIM project (Denitrification in Agricultural Soils: Integrated control and Modelling at various scales) for an area of 13 m² grassland. For this purpose, 3200 cost effective dropper bottles were made and placed onto acrylic sheets closely above ground to set the pattern and spacing of infiltration points. Each dropper bottle provides a reservoir for each infiltration point, resulting in an even distribution of the tracer solution over the soil surface. A reliable dripping speed (100 ml ≙ 55 min +/-5 min) is assured by individual cannulas (0.8 mm x 120 mm) at the tip of each dropper bottle. Dripping can be started fast by removing a rubber stopper at the bottom of the bottle. The areas were split into two sets for application with each finishing within 2 hours with an acceptable failure rate. Tracer application by dropper bottles therefore represents a new, noninvasive and infiltration optimized application method for large field experiments. To solve problems arising from different tracer retention i.e. nitrate (NO3-) and ammonium (NH4+) invasive methods would be needed.
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