title: Complexation of trace organic contaminants with fractionated dissolved organic matter: implications for mass spectrometric quantification.
abstract: Interaction with aqueous phase dissolved organic matter (DOM) can alter the fate of trace organic contaminants of emerging concern once they enter the water cycle. In order to probe possible DOM binding mechanisms and their consequences for contaminant detection and quantification in natural waters, a set of laboratory experiments was conducted with aqueous solutions containing various operationally-defined "hydrophilic" and "hydrophobic" freshwater DOM fractions isolated by resin adsorption techniques from reference Suwannee River natural organic matter (SROM). Per unit mass of SROM carbon, hydrophobic acids (HoA) comprised the largest C fraction (0.63±0.029), followed by hydrophilic-neutrals (HiN, 0.11±0.01) and acids (HiA, 0.09±0.017). Aqueous solutions comprising 8mgL(-1) DOC of each SROM fraction were spiked with a concentration range (10-1000μgL(-1)) of bisphenol A (BPA), carbamazepine (CBZ), or ibuprofen (IBU) as model target compounds in 24mM NH4HCO3 background electrolyte at pH 7.4. Contaminant interaction with the SROM fractions was probed using fluorescence spectroscopy, and effects on quantitative analysis of the target compounds were measured using direct aqueous-injection liquid chromatography tandem mass spectrometry (LC-MS/MS). Total quenching was greater for the hydrophilic fractions of SROM and associations were principally with protein-like and fulvic acid-like constituents. Whereas LC-MS/MS recoveries indicated relatively weak interactions with most SROM factions, an important exception was the HiA fraction, which diminished recovery of CBZ and IBU by ca. 30% and 70%, respectively, indicating relatively strong molecular interactions.
authors.affiliation: Department of Soil, Water and Environmental Science, University of Arizona, 1177 E 4th St., Tucson, AZ 85721, USA. selene.hernandez27@gmail.com
authors.forename: Selene Hernandez
authors.initials: SH
authors.lastname: Ruiz
authors.forename: Samanthi
authors.initials: S
authors.lastname: Wickramasekara
authors.forename: Leif
authors.initials: L
authors.lastname: Abrell
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Gao
authors.forename: Benny
authors.initials: B
authors.lastname: Chefetz
authors.forename: Jon
authors.initials: J
authors.lastname: Chorover
mesh_terms: D000327:Adsorption; D001559:Benzhydryl Compounds / Q000032:analysis; D002220:Carbamazepine / Q000032:analysis; D004784:Environmental Monitoring; D005618:Fresh Water / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D013058:Mass Spectrometry; D010636:Phenols / Q000032:analysis; D012995:Solubility; D014874:Water Pollutants, Chemical / Q000032:analysis*; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D002220:Carbamazepine; D010636:Phenols; D014874:Water Pollutants, Chemical; C006780:bisphenol A; D000098826:Bisphenol A Compounds