title: Monomer-dimer equilibrium of nitroso-aromatic spin trap 3,5-dibromo-4-nitrosobenzenesulfonic acid, sodium salt (DBNBS), in aqueous solution.
abstract: 3,5-Dibromo-4-nitrosobenzenesulfonic acid, sodium salt (DBNBS), which is widely used as a spin trap in biological systems, was allowed to form the monomer-dimer equilibrium in aqueous solution, and its equilibrium constant (Kc) was determined by NMR measurement and visible spectrum analysis. The Kc values obtained from the two different methods were virtually identical and evaluated as 1.3 x 10(-3) mol dm-3 at 25 degrees C. Further, the molar extinction coefficient of DBNBS monomer (epsilon 760) was determined to be 34 dm3mol-1cm-1. The present results indicate that only a minor portion (ca. 20%) of dissolved DBNBS (10 mmol dm-3) is practically capable of spin trapping under the conditions most widely used in biological studies.
authors.affiliation: Department of Polymer Science and Engineering, Kyoto Institute of Technology, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ide
authors.forename: A
authors.initials: A
authors.lastname: Hagi
authors.forename: S
authors.initials: S
authors.lastname: Ohsumi
authors.forename: A
authors.initials: A
authors.lastname: Murakami
authors.forename: K
authors.initials: K
authors.lastname: Makino
mesh_terms: D001557:Benzenesulfonates / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009603:Nitroso Compounds / Q000737:chemistry*; D012996:Solutions; D013113:Spin Labels; D014867:Water
chemical_list: D001557:Benzenesulfonates; D009603:Nitroso Compounds; D012996:Solutions; D013113:Spin Labels; D014867:Water; C048757:3,5-dibromo-4-nitrosobenzenesulfonate