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Hydrochemistry and groundwater isotopes
Published in Ian Acworth, Investigating Groundwater, 2019
For hydrogen and oxygen isotopes of waters, the standard adopted is the Vienna Standard Mean Ocean Water (VSMOW). For carbon the standard is a marine carbonate fossil, the Vienna Pee Dee Belemnite (VPDB).
Dominant factors influencing changes in the water quantity and quality in the Dianshi Reservoir, East China
Published in Human and Ecological Risk Assessment: An International Journal, 2022
Fengmei Su, Peiyue Li, Misbah Fida
In addition, stable isotopes, δ2H and δ18O, were used to determine whether the precipitation is the main recharge source for the Dianshi Reservoir. Indeed, the isotopes δ2H and δ18O represent the variation degree of the hydrogen and oxygen isotopic compositions of the sample as compared to that of the standard VSMOW (Vienna Standard Mean Ocean Water) (Zhang et al. 2020). The δ2H and δ18O can be calculated according to the following formulas:where RHsample and RHstandard denote the value of 2H/H in the drinking water sample and VSMOW, respectively; ROsample and ROstandard denote the value of 18O/16O in the drinking water sample and the VSMOW, respectively.
Determination of the natural deuterium distribution of fatty acids by application of 2H 2D-NMR in liquid crystals: fundamentals, advances, around and beyond
Published in Liquid Crystals, 2020
The isotope ratio value (2H/1H) using (fresh) ocean water molecules (known as V-SMOW value: Vienna-Standard Mean Ocean Water) has been set at 1.5576 × 10−2% (155,76 ppm) for hydrogen atoms. This value was promulgated by the International Atomic Energy Agency (based in Vienna) in 1968, and is still used as international standard value [10]. However, in natural hydrogenated compounds, significant changes in the isotope ratios (2H/1H) (up to 50%) can be observed at its different hydrogenated sites. This non-statistical intramolecular distribution of hydrogen isotope means that the content of different monodeuterated isotopomers depends on the deuterium-substituted position. These site-specific intramolecular variations define the isotopic fractionation of a molecule and characterise its isotopic profile. These profiles are unique molecular fingerprints that can be related to the geographical or botanical origin of a compound, and hence provide data sources in the fight against counterfeiting (adulteration, substitution, imitation of premium products), for instance [11]. From a theoretical point of view, the analysis of the isotopic profiles of a substrate/product pair can also makes it possible to study the primary or secondary kinetic isotopic effects (KIEs) [12], to identify hydrogen deuterium) sources, and thus to understand the enzymatic mechanisms leading to the synthesis/transformation of natural compounds [13–16].
Mineral characterisation of the non-sulphide Zn mineralisation of the Florida Canyon deposit, Bongará District, Northern Peru
Published in Applied Earth Science, 2019
Saulo Batista de Oliveira, Caetano Juliani, Lena Virgínia Soares Monteiro
For carbon and oxygen stable isotope analysis, a selective sampling of the oxidation zone was made, seeking zones of massive smithsonite. Four samples were obtained using a Dremel 3000 diamond drill. The isotope compositions were determined using the continuous flow method and a Thermo Finnigan GasBench II equipment coupled to a Delta V Advantage mass spectrometer at the Stable Isotope Laboratory of the University of São Paulo, Brazil (LIESP-USP). Isotope ratios were determined on CO2 gas released from carbonate minerals by the reaction with orthophosphoric acid at 72°C and corrected using the phosphoric acid fractionation factors given by Gilg et al. (2008) for smithsonite. Results are reported in conventional per mil notation (‰) relative to the Vienna Pee Dee Belemnite (VPDB) and the Vienna Standard Mean Ocean Water (VSMOW) standards for carbon and oxygen.