Implications of sample treatment on characterization of riverine dissolved organic matter. Issue 5 (13th April 2022)

• Record Type: Journal Article
• Authors: Nelson, Amelia R.; Toyoda, Jason; Chu, Rosalie K.; Tolić, Nikola; Garayburu-Caruso, Vanessa A.; Saup, Casey M.; Renteria, Lupita; Wells, Jacqueline R.; Stegen, James C.; Wilkins, Michael J.; Danczak, Robert E.
• Is Part Of: Environmental science. Volume 24:Issue 5(2022)
• Page Start: 773
• Page End: 782
• Publication Date: 2022-04-13
• Subjects: Environmental monitoring -- Periodicals; Biological monitoring -- Periodicals; Environmental chemistry -- Periodicals; 363.7363
• DOI: 10.1039/d2em00044j
• Languages: English
• ISSNs: 2050-7887

Abstract

Abstract : We compared how FTICR-MS characterization of riverine dissolved organic matter varied across four sample pre-treatment and instrument ionization methods to provide guidelines for future researchers utilizing FTICR-MS in environmental analyses. Abstract : High-resolution mass spectrometry techniques are widely used in the environmental sciences to characterize natural organic matter and, when utilizing these instruments, researchers must make multiple decisions regarding sample pre-treatment and the instrument ionization mode. To identify how these choices alter organic matter characterization and resulting conclusions, we analyzed a collection of 17 riverine samples from East River, CO (USA) under four PPL-based Solid Phase Extraction (SPE) treatment and electrospray ionization polarity ( e.g., positive and negative) combinations: SPE (+), SPE (−), non-SPE (−), and non-SPE (+). The greatest number of formula assignments were achieved with SPE-treated samples due to the removal of compounds that could interfere with ionization. Furthermore, the SPE (−) treatment captured the most formulas across the widest chemical compound diversity. In addition to a reduced number of assigned formulas, the non-SPE datasets resulted in altered thermodynamic interpretations that could cascade into incomplete assumptions about the availability of organic matter pools for heterotrophic microbial respiration. Thus, we infer that the SPE (−) treatment is the best single method for characterizing environmental organic matter pools unless the focus is on lipid-like compounds, in which case we recommend a combination of SPE (−) and SPE (+) to adequately characterize these molecules.