3 research outputs found
Compound-Specific Hydrogen Isotope Analysis of Heteroatom-Bearing Compounds via Gas Chromatography–Chromium-Based High-Temperature Conversion (Cr/HTC)–Isotope Ratio Mass Spectrometry
The traditional high-temperature
conversion (HTC) approach toward
compound-specific stable isotope analysis (CSIA) of hydrogen for heteroatom-bearing
(i.e., N, Cl, S) compounds has been afflicted by fractionation bias
due to formation of byproducts HCN, HCl, and H<sub>2</sub>S. This
study presents a chromium-based high-temperature conversion (Cr/HTC)
approach for organic compounds containing nitrogen, chlorine, and
sulfur. Following peak separation along a gas chromatographic (GC)
column, the use of thermally stable ceramic Cr/HTC reactors at 1100–1500
°C and chemical sequestration of N, Cl, and S by chromium result
in quantitative conversion of compound-specific organic hydrogen to
H<sub>2</sub> analyte gas. The overall hydrogen isotope analysis via
GC–Cr/HTC–isotope ratio mass spectrometry (IRMS) achieved
a precision of better than ± 5 mUr along the VSMOW-SLAP scale.
The accuracy of GC–Cr/HTC–IRMS was validated with organic
reference materials (RM) in comparison with online EA–Cr/HTC–IRMS
and offline dual-inlet IRMS. The utility and reliability of the GC–Cr/HTC–IRMS
system were documented during the routine measurement of more than
500 heteroatom-bearing organic samples spanning a δ<sup>2</sup>H range of −181 mUr to 629 mUr
The lowland stream monitoring dataset (KgM, Kleingewässer-Monitoring) 2018, 2019
Plant protection products in the environment are partly responsible for the progressive loss of biodiversity. The mostly insufficient ecological status of surface waters is often explained by habitat degradation and excessive nutrient input. But what role do plant protection products play in this context? The Kleingewässermonitoring (KgM) project provides a worldwide unique quantitative assessment of the impact of pesticides from diffuse agricultural sources on small and medium-sized streams. The dataset comprises 124 monitoring stream sections all over Germany covering a wide pollution gradient where consistent measurements were carried out in 2018 and 2019 during the major pesticide application period from April to July. These measurements include event-driven sampling to record surface rainfall-induced short-term peak concentrations in addition to regular grab sampling of pesticides and a wide range of other pollutants resulting in more than 1,000 water samples. All further relevant anthropogenic and environmental parameters reigning ecological stream quality were recorded comprehensively (morphological and stream bed structure, temperature, flow velocity, dissolved oxygen, pH, catchment land use, stream profile). The dataset also contains effect monitoring data featuring sampled invertebrate communities and bioassay analyses of water samples. The data enables an assessment of pesticide exposure and related effects as well as the analysis of complex causal relationships in streams