title: Combined HPLC/HPSEC study of Suwannee River Fulvic Acid adsorptive fractionation on α-aluminum oxide.
abstract: A novel liquid chromatographic (LC) method with repeated injections of Suwannee River Fulvic Acid (SRFA) was used to investigate its adsorptive fractionation by synthetic α-Al(2)O(3). Eluent (i.e., non-retained) SRFA for each injection was monitored by two ultraviolet (UV) absorbance detection channels (300 and 365 nm) and one fluorescence detection channel (λ(ex)=350 nm, λ(em)=450 nm). Preferential adsorption of SRFA constituents was revealed by the different responses of the three LC detection channels. Samples of non-retained SRFA from injections of three independent replicate experiments were collected and aggregated for subsequent analysis by steady state ultraviolet-visible (UV/vis) absorption spectrometry and size exclusion chromatography (SEC). The ratio of absorbance at 254 and 204 nm, a surrogate for specific UV absorbance at 254 nm, increased with increasing injection number for the non-retained SRFA, indicating the preferential adsorption of SRFA constituents containing aromatic moieties. SEC analysis confirmed the preferential adsorption of higher molecular weight (MW) SRFA constituents as the non-adsorbed SRFA fractions increased in MW across the series of injections. The SEC results also suggested that certain SRFA constituents in the ca. 2-5 kDa MW range adsorbed in early injections were displaced by higher MW species (ca. 5-10 kDa) in later injections.
authors.affiliation: Department of Chemistry, Georgia Southern University, Statesboro, GA 30458, United States. dkreller@georgiasouthern.edu
authors.forename: David I
authors.initials: DI
authors.lastname: Kreller
authors.forename: Mark A
authors.initials: MA
authors.lastname: Schlautman
authors.forename: Samantha L
authors.initials: SL
authors.lastname: McGunigale
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D001578:Benzopyrans / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D001578:Benzopyrans; D000537:Aluminum Oxide; C005023:fulvic acid