title: Chemiluminescent detection of catecholamines by generation of hydrogen peroxide with imidazole.
abstract: A novel detection method for catecholamines using imidazole was investigated using a chemiluminescence coupled flow injection system. Imidazole catalysed decomposition of catecholamines to generate hydrogen peroxide, then the hydrogen peroxide was detected by chemiluminescence. The optimal condition for generation of hydrogen peroxide from a catecholamine was to incubate the catecholamines (53 pmol) in an imidazole solution (50 mmol/L, pH 9.0, 1.0 mL) at 60 degrees C for 30 min. Peroxide-was detected by peroxyoxalate chemiluminescence, and the rank order of the light emission intensities was as follows; dopamine (100%) >epinephrine (78%) >L-DOPA (62%) >norepinephrine (58%) >deoxyepinephrine (51%) >isoproterenol (43%) >dihydroxybenzylamine (25%). The light intensities of the reaction mixtures (corresponding to 1.06 pmol catecholamines) varied depending on the chemiluminescence (CL) detection reaction, and the rank order of the light intensity was as follows; luminol CL catalysed with horseradish peroxidase (HRP) (371%) >peroxyoxalate chemiluminescence (100%) >luminol CL catalysed with ferrycyanide (62%) >lucigenin CL (15%) >pyrogallol CL (0.8%) >purpurogallin CL (0.4%) >luminol CL (0.3%). The luminol CL reaction catalysed by HRP is recommended for the detection of peroxide in this method for catecholamines.
authors.affiliation: Department of Clinical Pathology, Kinki University School of Medicine, 377-2, Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Nozaki
authors.forename: T
authors.initials: T
authors.lastname: Iwaeda
authors.forename: H
authors.initials: H
authors.lastname: Moriyama
authors.forename: Y
authors.initials: Y
authors.lastname: Kato
mesh_terms: D002395:Catecholamines / Q000032:analysis*; D004298:Dopamine / Q000032:analysis; D005069:Evaluation Studies as Topic; D006861:Hydrogen Peroxide / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007093:Imidazoles; D008163:Luminescent Measurements; D008165:Luminol; D012996:Solutions; D013696:Temperature
chemical_list: D002395:Catecholamines; D007093:Imidazoles; D012996:Solutions; D008165:Luminol; C029899:imidazole; D006861:Hydrogen Peroxide; D004298:Dopamine