title: Functionalized pyrolytic highly oriented graphite polymer film for surface-assisted laser desorption/ionization mass spectrometry in environmental analysis.
abstract: The pyrolytic highly oriented graphite polymer film (PGS) was first employed to analyze low-mass analytes in environmental analysis by surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). PGS is a synthetic uniform and highly oriented graphite polymer film with high thermal anisotropic conductivity. We have found that negative ion mode SALDI-MS using oxidized PGS (PGS-SALDI-MS) can be used to detect [M-H]- ions from perfluorooctanoic acid (PFOA) and other perfluoroalkylcarboxylic acids when the PGS surface is modified with the cationic polymer polyethyleneimine (PEI). The signal intensity of PFOA when employing the PEI modification showed a ten-fold increase over that obtained from desorption/ionization on porous silicon (DIOS). PFOA was quantified using PGS-SALDI-MS and the calibration curve showed a wide linear dynamic range of response (20-1000 ppb). The combination of atmospheric pressure ionization and PGS (AP-PGS-SALDI) showed greater signal intensity than vacuum PGS-SALDI for deprotonated PFOA. Several other environmentally important chemicals, including perfluoroalkylsulfonic acid, pentachlorophenol, bisphenol A, 4-hydroxy-2-chlorobiphenyl, and benzo[a]pyrene, were also successfully used to evaluate PGS-SALDI-MS. In addition, we found that nonafluoro-1-butanesulfonic acid was able to produce protonated peptides in positive ion PGS-SALDI-MS, but that perfluoropentanoic acid and trifluoroacetic acid were not. It is suggested that perfluoroalkylsulfonic acids are better protonating agents than perfluoroalkylcarboxylic acids in SALDI-MS.
authors.affiliation: Department of Applied Chemistry, Kansai University, Suita, Osaka 564-8680, Japan.
authors.forename: Hideya
authors.initials: H
authors.lastname: Kawasaki
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Takahashi
authors.forename: Hiroki
authors.initials: H
authors.lastname: Fujimori
authors.forename: Kouji
authors.initials: K
authors.lastname: Okumura
authors.forename: Takehiro
authors.initials: T
authors.lastname: Watanabe
authors.forename: Chisato
authors.initials: C
authors.lastname: Matsumura
authors.forename: Syusuke
authors.initials: S
authors.lastname: Takemine
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakano
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Arakawa
mesh_terms: D002210:Caprylates / Q000737:chemistry; D004785:Environmental Pollutants / Q000737:chemistry*; D005466:Fluorocarbons / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation* / Q000379:methods; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation* / Q000379:methods
chemical_list: D002210:Caprylates; D004785:Environmental Pollutants; D005466:Fluorocarbons; D011108:Polymers; D006108:Graphite; C023036:perfluorooctanoic acid