title: Bimolecular rate constant determination for the reaction of hydroxyl radicals with domoic and kainic acid in aqueous solution.
abstract: Bimolecular rate constants for the hydroxyl radical, .OH, reaction with domoic acid, kainic acid, and several model compounds were determined using electron pulse radiolysis and transient absorption spectroscopy. These oxidation rate constants were determined as (9.22 +/- 0.60) x 10(9) M(-1) s(-1) and (2.46 +/- 0.19) x 10(9) M(-1) s(-1), for domoic acid and kainic acid, respectively. Model compound rate constant measurements suggested that the conjugated double bond of the C4 substituent of domoic acid, and the double bond in kainic acid, were the preferential initial site of .OH reaction, which would destroy the conjugation and/or molecular conformation of these toxins. These reaction rate constants were also used to determine potential persistence in natural water systems, however the calculated half-life for domoic acid of approximately 34 days implies that significant photodegradation via .OH reaction mechanisms is unlikely.
authors.affiliation: Marine, Earth, and Atmospheric Science Department, North Carolina State University, Jordan Hall Raleigh, North Carolina 27695, USA.
authors.forename: Kimberly G
authors.initials: KG
authors.lastname: Jones
authors.forename: William J
authors.initials: WJ
authors.lastname: Cooper
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Mezykk
mesh_terms: D017665:Hydroxyl Radical / Q000737:chemistry*; D007608:Kainic Acid / Q000031:analogs & derivatives* / Q000032:analysis* / Q000737:chemistry; D008956:Models, Chemical; D015394:Molecular Structure; D010084:Oxidation-Reduction; D012996:Solutions; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D012996:Solutions; D014874:Water Pollutants, Chemical; D017665:Hydroxyl Radical; C012301:domoic acid; D007608:Kainic Acid