Diverse molecular compositions of dissolved organic matter derived from different composts using ESI FT-ICR MS

• Published in: Journal of environmental sciences (China) Vol. 99; pp. 80 - 89
• Main Authors: Liu, Minru, Tan, Yunkai, Fang, Kejing, Chen, Changya, Tang, Zhihua, Liu, Xiaoming, Yu, Zhen
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2021
• Subjects: Compost; Dissolved organic matter; ESI FT-ICR MS; Molecular characterization; Compost; Dissolved organic matter; Molecular characterization; ESI FT-ICR MS
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/j.jes.2020.06.011

•Molecular compositions of DOM in four composts were characterized by ESI FT-ICR MS.•The GWC DOM was the less saturated, more aromatic, and more oxidized compounds.•Similarities and differences of the four DOM molecular formulas were explored.•The unique compositions in four DOM samples showed higher MWw and oxygen contents.•Potential activities of the four composts during agricultural use were discussed. Dissolved organic matter (DOM) derived from various composts can promote significant changes of soil properties. However, little is known about the DOM compositions and their similarities and differences at the molecular level. In this study, the molecular compositions of DOM derived from kitchen waste compost (KWC), green waste compost (GWC), manure waste compost (MWC), and sewage sludge compost (SSC) were characterized by electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The molecular formulas were classified into four subcategories: CHO, CHON, CHOS, and CHONS. The KWC, MWC, and SSC DOM represented the highest fraction (35.8%-47.4%) of CHON subcategory, while the GWC DOM represented the highest fraction (68.4%) of CHO subcategory. The GWC DOM was recognized as the nitrogen- and sulfur-deficient compounds that were less saturated, more aromatic, and more oxidized compared with other samples. Further analysis of the oxygen, nitrogen-containing (N-containing), and sulfur-containing (S-containing) functional groups in the four subcategories revealed higher organic molecular complexity. Comparison of the similarities and differences of the four samples revealed 22.8% ubiquitous formulas and 17.4%, 11.1%, 10.7%, and 6.3% unique formulas of GWC, KWC, SSC, and MWC DOM, respectively, suggesting a large proportion of ubiquitous DOM as well as unique, source-specific molecular signatures. The findings presented herein provide new insight into the molecular characterization of DOM derived from various composts and demonstrated the potential role of these different compounds for agricultural utilization. Graphical abstract [Display omitted]