title: Determination and quantification of clonidine in human blood serum.
abstract: Clonidine ((2-[2,6-dichlorophenyl]amino)-2-imidazoline) preferentially stimulates central alpha(2)-adrenoceptors, which leads to inhibition of sympathetic tone, resulting in a lowering of arterial pressure and of heart rate. Additionally, many other desirable and undesirable effects are described, including analgesia, sedation and withdrawal reactions, which consist of a sudden rise in arterial pressure, nervousness, agitation and increased heart rate. The present study has the goal to develop a simple and effective method for the analysis of trace amounts of clonidine in human blood serum. Special emphasis is necessary to make application of electron impact ionization and separation of the analyte fragments in a quadruple mass analyzer suitable. The procedure comprises solid phase extraction followed by formation of the pentafluorobenzyl derivative. Further purification is achieved by phase transfer extraction into an acidic aqueous solution succeeded by re-extraction into dichloromethane. After solvent exchange, an aliquot is injected into the gas chromatograph equipped with a DB5 MS capillary column and a mass spectrometric detector. Chromatograms are recorded in single ion monitoring mode. Quantification is accomplished by internal standardization with moxonidine [4-chloro-5-(2-imidazolin-2-yl-amino)-6-methoxy-2-methylpyridine].
authors.affiliation: Institute for Analytical Chemistry, Micro- and Radiochemistry, Technical University of Graz, Technikerstr. 4, A 8010 Graz, Austria. wenzl@analytchem.tu-graz.ac.at
authors.forename: Thomas
authors.initials: T
authors.lastname: Wenzl
authors.forename: Ernst P
authors.initials: EP
authors.lastname: Lankmayr
authors.forename: Reinhold
authors.initials: R
authors.lastname: Wintersteiger
authors.forename: Anton
authors.initials: A
authors.lastname: Sadjak
authors.forename: Rudolf
authors.initials: R
authors.lastname: Likar
authors.forename: Dieter
authors.initials: D
authors.lastname: Zakel
mesh_terms: D001774:Blood Chemical Analysis / Q000295:instrumentation / Q000379:methods; D003000:Clonidine / Q000097:blood* / Q000302:isolation & purification; D008401:Gas Chromatography-Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008832:Microchemistry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003000:Clonidine