title: Solvent extraction of tricyclic amines from blood plasma and liquid chromatographic determination.
abstract: The extraction of seven tricyclic antidepressant amines from human plasma at different pH values was investigated for dichloromethane, diethyl ether and hexane--1-pentanol (95:5). The amines were extracted as bases and back-extracted to sulphuric acid, 0.10 mol/l, prior to the separation by bonded-phase liquid chromatography. Ether and hexane--1-pentanol (95:5) were most suitable, tertiary amines being best extracted at pH 8, and secondary amines at pH 10. Using ether, both while 15 min ws sufficient for hexane--1-pentanol (95:5). UV detection allowed concentrations down to 10 ng in 1 ml of plasma to be determined. Three ammonium ions--octylammonium, dimethylammonium, and trimethylammonium--were added as modifiers to the mobile phase containing acetonitrile in phosphoric acid, 0.10 mol/l. In the concentration interval 0.010--0.030 mol/l all of the amine modifiers gave on Polygosil C8 peak asymmetry factors of sufficiently low magnitude, while on Li-Chrosorb RP-18 this was so only for di- and trimethylammonium in a concentration of 0.030 mol/l.
mesh_terms: D000929:Antidepressive Agents, Tricyclic / Q000097:blood / Q000302:isolation & purification*; D002853:Chromatography, Liquid; D006801:Humans; D006863:Hydrogen-Ion Concentration; D012997:Solvents; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000929:Antidepressive Agents, Tricyclic; D012997:Solvents