title: Functionalized graphene-coated cobalt nanoparticles for highly efficient surface-assisted laser desorption/ionization mass spectrometry analysis.
abstract: Graphene-coated cobalt nanoparticles surface-functionalized with benzylamine groups (CoC-NH(2) nanomagnets) were shown to effectively enrich analytes for surface-assisted laser desorption/ionization mass spectrometry (affinity SALDI-MS) analysis. These CoC-NH(2) nanomagnets are highly suited for use with affinity SALDI-MS because their mean diameter of 30 nm, high specific surface area of 15 m(2) g(-1), and high-strength saturation magnetization of 158 emu g(-1) led to efficient extraction of analytes by magnetic separation, which in turn enabled excellent SALDI-MS performance. Surface modification of CoC nanomagnets with benzylamine groups increased the yield of peptide ions and decreased fragmentation of benzylpyridinium ions, so-called "thermometer ions" formed through soft ionization. The CoC-NH(2) nanomagnets were used to extract perfluorooctanesulfonate from large volumes of aqueous solutions by magnetic separation, which was identified directly by SALDI-MS analysis with high sensitivity even at the sub-part-per-trillion level (∼0.1 ng/L). The applicability of CoC-NH(2) nanomagnets in conjunction with SALDI-MS for the enrichment and detection of pentachlorophenol, bisphenol A, and polyfluorinated compounds (PFCs) with varying chain length, which are environmentally significant compounds, as well as small drugs, was also evaluated.
authors.affiliation: Department of Chemistry and Materials Engineering, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate-cho, Suita-shi, Osaka 564-8680, Japan. hkawa@kansai-u.ac.jp
authors.forename: Hideya
authors.initials: H
authors.lastname: Kawasaki
authors.forename: Keisuke
authors.initials: K
authors.lastname: Nakai
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Arakawa
authors.forename: Evagelos K
authors.initials: EK
authors.lastname: Athanassiou
authors.forename: Robert N
authors.initials: RN
authors.lastname: Grass
authors.forename: Wendelin J
authors.initials: WJ
authors.lastname: Stark
mesh_terms: D017738:Alkanesulfonic Acids / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D001596:Benzylamines / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry*; D005466:Fluorocarbons / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D006108:Graphite / Q000737:chemistry*; D059346:Magnets / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D017738:Alkanesulfonic Acids; D001596:Benzylamines; D005466:Fluorocarbons; D014867:Water; D003035:Cobalt; D006108:Graphite; C076994:perfluorooctane sulfonic acid; C030796:benzylamine