Use of electrospray ionization (ESI) mass spectrometry to investigate complex dissolved organic matter (DOM) and its potential applications in phytoplankton research

Harmful Algae ◽  
2008 ◽  
Vol 8 (1) ◽  
pp. 182-187 ◽  
Author(s):  
Rachel Sipler ◽  
Sybil Seitzinger
Keyword(s):  
Mass Spectrometry ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Electrospray Ionization ◽  
Potential Applications ◽  
Esi Mass Spectrometry

Natural dissolved organic matter affects electrospray ionization during analysis of emerging contaminants by mass spectrometry

2012 ◽  
Vol 717 ◽  
pp. 77-84 ◽  
Author(s):  
Samanthi Wickramasekara ◽  
Selene Hernández-Ruiz ◽  
Leif Abrell ◽  
Robert Arnold ◽  
Jon Chorover
Keyword(s):  
Mass Spectrometry ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Electrospray Ionization ◽  
Emerging Contaminants

scholarly journals High-field NMR spectroscopy and FTICR mass spectrometry: powerful discovery tools for the molecular level characterization of marine dissolved organic matter

2013 ◽  
Vol 10 (3) ◽  
pp. 1583-1624 ◽  
Author(s):  
N. Hertkorn ◽  
M. Harir ◽  
B. P. Koch ◽  
B. Michalke ◽  
P. Schmitt-Kopplin
Keyword(s):  
Mass Spectrometry ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Electrospray Ionization ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Molecular Level ◽  
13C Nmr Spectra ◽  
Fticr Ms

Abstract. High-performance, non-target, high-resolution organic structural spectroscopy was applied to solid phase extracted marine dissolved organic matter (SPE-DOM) isolated from four different depths in the open South Atlantic Ocean off the Angola coast (3° E, 18° S; Angola Basin) and provided molecular level information with extraordinary coverage and resolution. Sampling was performed at depths of 5 m (Angola Current; near-surface photic zone), 48 m (Angola Current; fluorescence maximum), 200 m (still above Antarctic Intermediate Water, AAIW; upper mesopelagic zone) and 5446 m (North Atlantic Deep Water, NADW; abyssopelagic, ~30 m above seafloor) and produced SPE-DOM with near 40% carbon yield and beneficial nuclear magnetic resonance (NMR) relaxation properties, a crucial prerequisite for the acquisition of NMR spectra with excellent resolution. 1H and 13C NMR spectra of all four marine SPE-DOM showed smooth bulk envelopes, reflecting intrinsic averaging from massive signal overlap, with a few percent of visibly resolved signatures and variable abundances for all major chemical environments. The abundance of singly oxygenated aliphatics and acetate derivatives in 1H NMR spectra declined from surface to deep marine SPE-DOM, whereas C-based aliphatics and carboxyl-rich alicyclic molecules (CRAM) increased in abundance. Surface SPE-DOM contained fewer methyl esters than all other samples, likely a consequence of direct exposure to sunlight. Integration of 13C NMR spectra revealed continual increase of carboxylic acids and ketones from surface to depth, reflecting a progressive oxygenation, with concomitant decline of carbohydrate-related substructures. Aliphatic branching increased with depth, whereas the fraction of oxygenated aliphatics declined for methine, methylene and methyl carbon. Lipids in the oldest SPE-DOM at 5446 m showed a larger share of ethyl groups and methylene carbon than observed in the other samples. Two-dimensional NMR spectra showed exceptional resolution and depicted resolved molecular signatures in excess of a certain minimum abundance. Classical methyl groups terminating aliphatic chains represented ~15% of total methyl in all samples investigated. A noticeable fraction of methyl (~2%) was bound to olefinic carbon. Methyl ethers were abundant in surface marine SPE-DOM, and the chemical diversity of carbohydrates was larger than that of freshwater and soil DOM. In all samples, we identified sp2-hybridized carbon chemical environments with discrimination of isolated and conjugated olefins and α,β-unsaturated double bonds. Olefinic proton and carbon atoms were more abundant than aromatic ones; olefinic unsaturation in marine SPE-DOM will be more directly traceable to ultimate biogenic precursors than aromatic unsaturation. The abundance of furan, pyrrol and thiophene derivatives was marginal, whereas benzene derivatives, phenols and six-membered nitrogen heterocycles were prominent; a yet unassigned set of six-membered N-heterocycles with likely more than one single nitrogen occurred in all samples. Various key polycyclic aromatic hydrocarbon substructures suggested the presence of thermogenic organic matter at all water depths. Progressive NMR cross-peak attenuation from surface to deep marine SPE-DOM was particularly strong in COSY NMR spectra and indicated a continual disappearance of biosignatures as well as entropy gain from an ever increased molecular diversity. Nevertheless, a specific near-seafloor SPE-DOM signature of unsaturated molecules recognized in both NMR and Fourier transform ion cyclotron mass spectrometry (FTICR/MS) possibly originated from sediment leaching. The conformity of key NMR and FTICR/MS signatures suggested the presence of a large set of identical molecules throughout the entire ocean column even though the investigated water masses belonged to different oceanic regimes and currents. FTICR/MS showed abundant CHO, CHNO, CHOS and CHNOS molecular series with slightly increasing numbers of mass peaks and average mass from surface to bottom SPE-DOM. The proportion of CHO and CHNO negative ions increased from surface to depth, whereas CHOS and especially CHNOS molecular series markedly declined. While certain rather aliphatic CHOS and CHNOS ions were observed solely in the surface, deep marine SPE-DOM was enriched in unique unsaturated and rather oxygenated CHO and CHNO molecular series. With the exception of abyssopelagic SPE-DOM at 5446 m, which showed a peculiar CHOS chemistry of unsaturated carbon and reduced sulphur (black sulphur), CHO and CHNO molecular series contributed ~87% to total positive electrospray ionization FTICR mass peak integral, with a near constant ratio of CHNO / CHO molecular compositions near 1.13 ± 0.05. In case of all four marine SPE-DOM, remarkably disparate average elemental compositions as determined from either MS and NMR spectra were observed, caused by a pronounced ionization selectivity in electrospray ionization FTICR/MS. The study demonstrates that the exhaustive characterization of complex unknowns in marine DOM will enable a meaningful classification of individual marine biogeosignatures. Future in-depth functional biodiversity studies with a clear understanding of DOM structure and function might eventually lead to a novel, unified perception of biodiversity and biogeochemistry.

scholarly journals Spatiotemporal transformation of dissolved organic matter along an alpine stream flow path on the Qinghai–Tibet Plateau: importance of source and permafrost degradation

2018 ◽  
Vol 15 (21) ◽  
pp. 6637-6648 ◽  
Author(s):  
Yinghui Wang ◽  
Robert G. M. Spencer ◽  
David C. Podgorski ◽  
Anne M. Kellerman ◽  
Harunur Rashid ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Molecular Level ◽  
Tibet Plateau ◽  
Permafrost Degradation ◽  
Hydrological Conditions ◽  
14C Age ◽  
Alpine Stream ◽  
Qinghai Tibet Plateau

Abstract. The Qinghai–Tibet Plateau (QTP) accounts for approximately 70 % of global alpine permafrost and is an area sensitive to climate change. The thawing and mobilization of ice-rich and organic-carbon-rich permafrost impact hydrologic conditions and biogeochemical processes on the QTP. Despite numerous studies of Arctic permafrost, there are no reports to date for the molecular-level in-stream processing of permafrost-derived dissolved organic matter (DOM) on the QTP. In this study, we examine temporal and spatial changes of DOM along an alpine stream (3850–3207 m above sea level) by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), accelerator mass spectrometry (AMS) and UV–visible spectroscopy. Compared to downstream sites, dissolved organic matter (DOM) at the headstream site exhibited older radiocarbon age, higher mean molecular weight, higher aromaticity and fewer highly unsaturated compounds. At the molecular level, 6409 and 1345 formulas were identified as unique to the active layer (AL) leachate and permafrost layer (PL) leachate, respectively. Comparing permafrost leachates to the downstream site, 59 % of AL-specific formulas and 90 % of PL-specific formulas were degraded, likely a result of rapid in-stream degradation of permafrost-derived DOM. From peak discharge in the summer to low flow in late autumn, the DOC concentration at the headstream site decreased from 13.9 to 10.2 mg L−1, while the 14C age increased from 745 to 1560 years before present (BP), reflecting an increase in the relative contribution of deep permafrost carbon due to the effect of changing hydrological conditions over the course of the summer on the DOM source (AL vs. PL). Our study thus demonstrates that hydrological conditions impact the mobilization of permafrost carbon in an alpine fluvial network, the signature of which is quickly lost through in-stream mineralization and transformation.

scholarly journals Poly(ethyleneglycol) in electrospray ionization (ESI) mass spectrometry

Analusis ◽  
2000 ◽  
Vol 28 (4) ◽  
pp. 263-268 ◽  
Author(s):  
S. Varray ◽  
J.-L. Aubagnac ◽  
F. Lamaty ◽  
R. Lazaro ◽  
J. Martinez ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Electrospray Ionization ◽  
Esi Mass Spectrometry
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