A novel high‐temperature combustion based system for stable isotope analysis of dissolved organic carbon in aqueous samples. II: optimization and assessment of analytical performance

Kirkels, Frédérique; Cerli, Chiara; Federherr, Eugen; Gao, Jun; Kalbitz, Karsten

doi:10.1002/rcm.7053

Cited by 27 publications

(21 citation statements)

References 54 publications

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“…The TOC instrument uses a common high-temperature catalytic combustion method (Kirkels et al, 2014). The analytical method is fully described in Kim et al (2015).…”

Section: Methodsmentioning

confidence: 99%

Sources, fluxes, and behaviors of fluorescent dissolved organic matter (FDOM) in the Nakdong River Estuary, Korea

Lee¹,

Kim²

2018

Biogeosciences

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Abstract. We monitored seasonal variations in dissolved organic carbon (DOC), the stable carbon isotope of DOC (δ 13 C-DOC), and fluorescent dissolved organic matter (FDOM) in water samples from a fixed station in the Nakdong River Estuary, Korea. Sampling was performed every hour during spring tide once a month from October 2014 to August 2015. The concentrations of DOC and humic-like FDOM showed significant negative correlations against salinity (r 2 = 0.42-0.98, p < 0.0001), indicating that the river-originated DOM components were the major source and behave conservatively in the estuarine mixing zone. The extrapolated δ 13 C-DOC values (−27.5 to −24.5 ‰) in fresh water confirm that both components are mainly of terrestrial origin. The slopes of humic-like FDOM against salinity were 60-80 % higher in the summer and fall due to higher terrestrial production of humic-like FDOM. The slopes of proteinlike FDOM against salinity, however, were 70-80 % higher in spring due to higher biological production in river water. Our results suggest that there are large seasonal changes in riverine fluxes of humic-and protein-like FDOM to the ocean.

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“…The TOC instrument uses a common high-temperature catalytic combustion method (Kirkels et al, 2014). The analytical method is fully described in Kim et al (2015).…”

Section: Methodsmentioning

confidence: 99%

Sources, fluxes, and behaviors of fluorescent dissolved organic matter (FDOM) in the Nakdong River Estuary, Korea

Lee¹,

Kim²

2018

Biogeosciences

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“…One interlaboratory comparison study has confirmed a significant discrepancy in the results obtained for the same samples analyzed using different instruments, laboratory protocols, and normalization procedures . Several laboratories still use the δ 13 C values of high‐pressure CO 2 gas cylinders for normalization of measured δ 13 C values to the VPDB scale, e.g . Normalization to the value of the gas reference is the simplest and easiest method to apply; however, in light of the findings of Paul et al and Skrzypek, it also leads to the lowest accuracy among all known normalization methods and should be considered as inappropriate.…”

Section: Introductionmentioning

confidence: 99%

“…[6][7][8] At present, these types of analyses are usually performed using continuous-flow systems employing a wet chemical oxidation (WCO) technique combined with isotope ratio mass spectrometry (IRMS). These WCO-IRMS systems can be total organic carbon (TOC) analyzers [9][10][11] or instruments that couple high-performance liquid chromatography (HPLC) with IRMS. 12,13 The concept of combining HPLC with IRMS was introduced by Thermo Fisher Scientific, and their LC-IsoLink system (Thermo Fisher Scientific, Bremen, Germany) has been available commercially since 2004 and is designed for the stable carbon isotope analysis of a broad spectrum of non-volatile compounds dissolved in water.…”

Section: Introductionmentioning

confidence: 99%

Reference materials selection for the stable carbon isotope analysis of dissolved carbon using a wet oxidation system

Skrzypek

Ford

2019

Rapid Comm Mass Spectrometry

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Rationale Wet chemical oxidation combined with isotope ratio mass spectrometry has become a routine technique for analyzing the stable carbon isotope composition of dissolved organic (DOC) and inorganic (DIC) carbon. However, methodological inconsistencies between laboratories in using different reference materials lead to a discrepancy in results. We experimentally tested the precision and accuracy of the analysis of commonly available international reference materials and other chemicals potentially suitable for laboratory standards. Methods The solid international reference materials and other simple chemicals were used to prepare water solutions. A range of carbon concentrations was chosen to optimize tests for (1) precision and accuracy, (2) linearity, (3) detection limits, (4) memory effects, and (5) efficiency of DIC removal from a DOC/DIC mixtures. Samples were analyzed using an LC‐IsoLink coupled with a Delta V Plus isotope ratio mass spectrometer (Thermo Fisher Scientific). Results The analytical setup had a negligible memory effect, good reproducibility (<0.21‰) and accuracy (maximum difference from the true values <0.35‰) for the analyzed organic compounds if approximately ≥9 × 10−09 moles of dissolved carbon was injected into the system (~11 mg C L−1 if a 10‐μL loop was used). Analyses of sodium bicarbonate or calcium carbonate solutions had a two‐fold lower accuracy despite maintaining a high precision. Conclusions Aqueous solutions of international reference materials such as L‐glutamic acids (USGS40, USGS41), benzoic acid (IAEA‐601) and sucrose (IAEA‐CH‐6) can be successfully used for direct normalization of results to the VPDB scale. By contrast, analyses of caffeine and urea returned very reproducible but highly inaccurate results and these materials are not recommended for standards.

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“…3B). However, marine phytoplankton and dissolved organic matter, which can be a major source for bacteria respiration (Maher and Eyre, 2010), tend to have lower values between À20& and 24& (Goericke et al, 1994;Kirkels et al, 2014). In contrast, CaCO 3 dissolution should contribute heavier carbon with d 13 C = À2& (Grottoli, 2000;McConnaughey, 2003).…”

Section: Sources Of Dic and Diel Variation In D 13 C Dicmentioning

confidence: 94%

Drivers of carbon isotopic fractionation in a coral reef lagoon: Predominance of demand over supply

Carvalho

Santos

Maher

et al. 2015

Geochimica et Cosmochimica Acta

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A novel high‐temperature combustion based system for stable isotope analysis of dissolved organic carbon in aqueous samples. II: optimization and assessment of analytical performance

Cited by 27 publications

References 54 publications

Sources, fluxes, and behaviors of fluorescent dissolved organic matter (FDOM) in the Nakdong River Estuary, Korea

Sources, fluxes, and behaviors of fluorescent dissolved organic matter (FDOM) in the Nakdong River Estuary, Korea

Reference materials selection for the stable carbon isotope analysis of dissolved carbon using a wet oxidation system

Drivers of carbon isotopic fractionation in a coral reef lagoon: Predominance of demand over supply

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