title: Online induction heating for determination of isotope composition of woody stem water with laser spectrometry: a methods assessment.
abstract: Application of stable isotopes of water to studies of plant-soil interactions often requires a substantial preparatory step of extracting water from samples without fractionating isotopes. Online heating is an emerging approach for this need, but is relatively untested and major questions of how to best deliver standards and assess interference by organics have not been evaluated. We examined these issues in our application of measuring woody stem xylem of sagebrush using a Picarro laser spectrometer with online induction heating. We determined (1) effects of cryogenic compared to induction-heating extraction, (2) effects of delivery of standards on filter media compared to on woody stem sections, and (3) spectral interference from organic compounds for these approaches (and developed a technique to do so). Our results suggest that matching sample and standard media improves accuracy, but that isotopic values differ with the extraction method in ways that are not due to spectral interference from organics.
authors.affiliation: a U.S. Geological Survey , Forest and Rangeland Ecosystem Science Center , Boise , ID , USA.
authors.forename: Brynne E
authors.initials: BE
authors.lastname: Lazarus
authors.affiliation: a U.S. Geological Survey , Forest and Rangeland Ecosystem Science Center , Boise , ID , USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Germino
authors.affiliation: a U.S. Geological Survey , Forest and Rangeland Ecosystem Science Center , Boise , ID , USA.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Vander Veen
mesh_terms: D019306:Artemisia / Q000737:chemistry*; D003903:Deuterium / Q000032:analysis; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D006361:Heating; D007834:Lasers; D009862:Online Systems; D010103:Oxygen Isotopes / Q000032:analysis; D018547:Plant Stems / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012987:Soil / Q000737:chemistry; D013057:Spectrum Analysis; D014867:Water / Q000737:chemistry*; D052584:Xylem / Q000737:chemistry
chemical_list: D010103:Oxygen Isotopes; D012987:Soil; D014867:Water; D003903:Deuterium
keywords: hydrogen-2; isotope measurements, methods and equipment; laser spectroscopy; oxygen-18; water; woody stem