title: Evaluation of a simple plasma catecholamine extraction procedure prior to high-performance liquid chromatography and electrochemical detection.
abstract: The modified extraction method for catecholamines described in this study is reproducible, simple, rapid, economical and relatively hazard-free. This method is based on the principle that plasma catecholamines are selectively adsorbed on acid-washed alumina at pH 8.6 and then eluted at a pH between 1.0 and 2.0. No statistically significant differences were obtained by using either 0.5 or 1.0 ml of plasma with 0.5 or 1.0 ml of Tris buffer. A 15-min mixing time during the adsorption and desorption steps was found to be practical, but any standardized time up to 1 h can be used. If the washing step was omitted, the catecholamines could not be eluted from the acid-washed alumina. To prevent dilution, the alumina had to be centrifuged and not aspirated to dryness after the washing step. An amount of 50 mg of WA-4 alumina was found to be the most practical in this study. Extracted or unextracted plasma as well as catecholamine standards were stable for four months at -20 degrees C.
authors.affiliation: Department of General Physiology, Dental School, University of Witwatersrand, Johannesburg, South Africa.
authors.forename: M F
authors.initials: MF
authors.lastname: Ganhao
authors.forename: J
authors.initials: J
authors.lastname: Hattingh
authors.forename: M L
authors.initials: ML
authors.lastname: Hurwitz
authors.forename: N I
authors.initials: NI
authors.lastname: Pitts
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide; D000818:Animals; D001800:Blood Specimen Collection; D002851:Chromatography, High Pressure Liquid; D003080:Cold Temperature; D004298:Dopamine / Q000097:blood*; D004355:Drug Stability; D004837:Epinephrine / Q000097:blood*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009638:Norepinephrine / Q000097:blood*; D011817:Rabbits; D014325:Tromethamine
chemical_list: D014325:Tromethamine; D000537:Aluminum Oxide; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine