title: Characterization and liquid chromatography-MS/MS based quantification of hydroxylated fullerenes.
abstract: Highly water-soluble hydroxylated fullerene derivatives are being investigated for a wide range of commercial products as well as for potential cytotoxicity. However, no analytical methods are currently available for their quantification at sub-ppm concentrations in environmental matrixes. Here, we report on the development and comparison of liquid chromatography-ultraviolet/visible spectroscopy (LC-UV/vis) and liquid chromatography-mass spectrometry (LC-MS) based detection and quantification methods for commercial fullerols. We achieved good separation efficiency using an amide-type hydrophilic interaction liquid chromatography (HILIC) column (plate number >2000) under isocratic conditions with 90% acetonitrile as the mobile phase. The method detection limits (MDLs) ranged from 42.8 ng/mL (UV detection) to 0.19 pg/mL (using MS with multiple reaction monitoring, MRM). Other MS measurement modes achieved MDLs of 125 pg/mL (single quad scan, Q1) and 1.5 pg/mL (multiple ion monitoring, MI). Each detection method exhibited a good linear response over several orders of magnitude. Moreover, we tested the robustness of these methods in the presence of Suvanee River fulvic acids (SRFA) as an example of organic matter commonly found in environmental water samples. While SRFA significantly interfered with UV- and Q1-based quantifications, the interference was relatively low using MI or MRM (relative error in presence of SRFA: 8.6% and 2.5%, respectively). This first report of a robust MS-based quantification method for modified fullerenes dissolved in water suggests the feasibility of implementing MS techniques more broadly for identification and quantification of fullerols and other water-soluble fullerene derivatives in environmental samples.
authors.affiliation: School of Sustainable Engineering and The Built Environment, Department of Chemistry and Biochemistry, The Biodesign Institute at Arizona State University, Arizona State University, Tempe, Arizona 85287, United States.
authors.forename: Tzu-Chiao
authors.initials: TC
authors.lastname: Chao
authors.forename: Guixue
authors.initials: G
authors.lastname: Song
authors.forename: Nicole
authors.initials: N
authors.lastname: Hansmeier
authors.forename: Paul
authors.initials: P
authors.lastname: Westerhoff
authors.forename: Pierre
authors.initials: P
authors.lastname: Herckes
authors.forename: Rolf U
authors.initials: RU
authors.lastname: Halden
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D037741:Fullerenes / Q000032:analysis*; D006900:Hydroxylation; D046529:Microscopy, Electron, Transmission; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013056:Spectrophotometry, Ultraviolet; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D037741:Fullerenes