title: Molecular characterization of lake sediment WEON by Fourier transform ion cyclotron resonance mass spectrometry and its environmental implications.
abstract: The compositional properties of water-extractable organic nitrogen (WEON) affect its behavior in lake ecosystems. This work is the first comprehensive study using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) for the characterization of the molecular composition of WEON in lake sediment. In sediments of Erhai Lake in China, this study found complex WEON species, with N-containing compounds in the northern, central, and southern regions contributing 34.47%, 42.44%, and 40.6%, respectively, of total compounds. Additionally, a van Krevelen diagram revealed that lignin components were dominant in sediment WEON structures (68% of the total), suggesting terrestrial sources. Furthermore, this study applied ESI-FT-ICR-MS to the examination of the environmental processes of lake sediment WEON on a molecular level. The results indicated that sediment depth impacted WEON composition and geochemical processes. Compared with other ecosystems, the double bond equivalent (DBE) value was apparently lower in Erhai sediment, indicating the presence of relatively fewer and smaller aromatic compounds. In addition, the presence of a large number of N-containing species and abundant oxidized nitrogen functional compounds that were likely to biodegrade may have further increased the potential releasing risk of WEON from Erhai sediment under certain environmental conditions.
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; Yunnan Key Laboratory of Pollution Process and Management of Plateau Lake-Watershed, Kunming, Yunnan Province, 650034, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; Yunnan Key Laboratory of Pollution Process and Management of Plateau Lake-Watershed, Kunming, Yunnan Province, 650034, China.
authors.forename: Shengrui
authors.initials: S
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; Atmospheric Chemistry and Aerosol Research Division, Chinese Research Academy of Environmental Science, Beijing, 100012, China.
authors.forename: Yisheng
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Shi
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; Yunnan Key Laboratory of Pollution Process and Management of Plateau Lake-Watershed, Kunming, Yunnan Province, 650034, China.
authors.forename: Haichao
authors.initials: H
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China; State Environmental Protection Key Laboratory for Lake Pollution Control, Research Center of Lake Eco-environment, Chinese Research Academy of Environmental Sciences, Beijing, 100012, China.
authors.forename: Jiachun
authors.initials: J
authors.lastname: Yang
mesh_terms: D017357:Cyclotrons; D005583:Fourier Analysis; D060106:Lakes; D013058:Mass Spectrometry; D009584:Nitrogen
chemical_list: D009584:Nitrogen
keywords: Dissolved organic nitrogen; Fourier transform ion cyclotron resonance; Lake sediment; Molecular-level characterization