Characterization of atmospheric organic matter using size-exclusion chromatography with inline organic carbon detection

Size separation method for absorption characterization in brown carbon: Application to an aged biomass burning sample

“…SEC absorption density of an aqueous extract of Suwannee River Humic Acid (SRHA, Figure 1b), a standard commonly considered structurally similar to atmospheric BrC, shows a single population with an absorption front at roughly 20,000 amu, with an absorption maximum at 4500 amu (see supporting information Text S1). The SRHA size observations are consistent with previous studies [Klaus et al, 2000;Her et al, 2002aHer et al, , 2002bWang et al, 2013]. The SEC absorption density plot for the aqueous BB extract in Figure 1a also shows appreciable absorption into the visible region.…”

“…Although this is an excellent technique for the separation of small molecules, it is not suitable for the analysis of oligomeric or polymeric species, with the exception of highly hydrophilic proteins [Issaq, 2001]. In contrast, size exclusion chromatography (SEC) has successfully been used to characterize large molecular weight components of environmentally derived natural organic matter, such as humic acids, thought to be compositionally similar to light-absorbing ELVOCs [Mukai and Ambe, 1986a;Klaus et al, 2000;Her et al, 2002aHer et al, , 2002bJanoš, 2003;Wang et al, 2013]. In contrast, size exclusion chromatography (SEC) has successfully been used to characterize large molecular weight components of environmentally derived natural organic matter, such as humic acids, thought to be compositionally similar to light-absorbing ELVOCs [Mukai and Ambe, 1986a;Klaus et al, 2000;Her et al, 2002aHer et al, , 2002bJanoš, 2003;Wang et al, 2013].…”

“…If large, hydrophobic ELVOCs can be eluted from the column using this technique, it is suspected that there will be little to no resolution between components. In contrast, size exclusion chromatography (SEC) has successfully been used to characterize large molecular weight components of environmentally derived natural organic matter, such as humic acids, thought to be compositionally similar to light-absorbing ELVOCs [Mukai and Ambe, 1986a;Klaus et al, 2000;Her et al, 2002aHer et al, , 2002bJanoš, 2003;Wang et al, 2013]. SEC separates components based solely on their molecular volume, which is primarily a function of the molecular weight of a compound.…”

Chlorine addition prior to granular activated carbon contactors improves trihalomethane control

“…Molecular weight distribution of NOM was characterized using size exclusion chromatography with in‐line DOC detection (SEC‐DOC) (Wang, Chiu, Westerhoff, Valsaraj, & Herckes, ). The SEC‐DOC system consists of a high‐performance liquid chromatography system (Waters 2695 Separation Module, Millford, MA) followed by photodiode array detector (Waters 2998, Millford, MA), TOC detector (Sievers Total Organic Carbon Analyzer 800), and inorganic carbon remover (900 ICR, GE, Boston, MA).…”

Unraveling the complexity of atmospheric brown carbon produced by smoldering boreal peat using size-exclusion chromatography with selective mobile phases

“…34 Additional uncertainties arise from intra-and intermolecular interactions, which can influence analyte hydrodynamic volume (e.g., via coiling, expansion, and aggregation/agglomeration), thereby leading to either early or delayed elution and corresponding overestimates or underestimates in MW. 36,44 Although the challenges associated with these secondary effects have been acknowledged in the broader atmospheric literature, 45,46 studies of BrC using this technique have largely assumed that size exclusion is the dominant separation mechanism. However, as BrC consists of a complex mixture of compounds with a wide range of polarities and sizes, 7 and with the potential to undergo aggregation and/or dissociation with changes in solvent environment, 47,48 this assumption warrants critical assessment.…”