title: Characterization of biodegradation intermediates of nonionic surfactants by MALDI-MS. 2. Oxidative biodegradation profiles of uniform octylphenol polyethoxylate in 18O-labeled water.
abstract: This paper reports the characterization of the biodegradation intermediates of octylphenol octaethoxylate (OP(8)EO) by means of matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The biodegradation test study was carried out in a pure culture (Pseudomonas putida S-5) under aerobic conditions using OP(8)EO as the sole carbon source and (18)O-labeled water as an incubation medium. In the MALDI-MS spectra of biodegraded samples, a series of OP(n)EO molecules with n = 2-8 EO units and their corresponding carboxylic acid products (OP(n)EC) were observed. The use of purified OP(8)EO enabled one to distinguish the shortened OPEO molecules as biodegradation intermediates. Furthermore, the formation of OP(8)EC (the oxidized product of OP(8)EO) supported the notion that terminal oxidation is a step in the biodegradation process. When biodegradation study was carried out in (18)O-labeled water, incorporation of (18)O atoms into the carboxyl group was observed for OPEC, while no incorporation was observed for the shortened OPEO products. These results could provide some rationale to the biodegradation mechanism of alkylphenol polyethoxylates.
authors.affiliation: Measurement Technology Group, Institute for Environmental Management Technology, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8569, Japan. sato-hiroaki@aist.go.jp
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Sato
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shibata
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Hiroto
authors.initials: H
authors.lastname: Tamura
mesh_terms: D001673:Biodegradation, Environmental; D008968:Molecular Conformation; D017830:Octoxynol / Q000737:chemistry* / Q000302:isolation & purification / Q000493:pharmacokinetics; D010084:Oxidation-Reduction; D010103:Oxygen Isotopes; D016958:Pseudomonas putida / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D013501:Surface-Active Agents / Q000737:chemistry* / Q000493:pharmacokinetics; D014867:Water
chemical_list: D010103:Oxygen Isotopes; D013501:Surface-Active Agents; D014867:Water; D017830:Octoxynol