Determination of plasma amitriptyline by electron-capture gas chromatography after oxidation to anthraquinone.
A selective procedure is described for the determination of amitriptyline in plasma. The method involves extraction, separation of amitriptyline from its metabolites and subsequent oxidation by ceric sulphate in 5.4 M sulphuric acid. The oxidation product, anthraquinone, is determined by means of electron-capture gas chromatography. The metabolites were separated by a column chromatographic extraction technique. The choice of oxidation reagent, optimum conditions for the oxidation, and the electron-capture properties of anthraquinone are discussed. The method can be used to determine down to 2 ng of amitriptyline in a plasma sample; the relative standard deviation at the 50-ng level was 4.0% (n = 8). The levels of amitriptyline found in a series of plasma samples are compared with those obtained by gas chromatography with use of nitrogen-specific detection; the two techniques gave coincident results.
D000639:Amitriptyline / Q000097:blood*; D000880:Anthraquinones / Q000032:analysis*; D002849:Chromatography, Gas / Q000379:methods*; D006801:Humans; D008722:Methods; D010084:Oxidation-Reduction
D000880:Anthraquinones; D000639:Amitriptyline