Gas chromatographic−mass spectrometric method for trazodone and a deuterated analogue in plasma

Abstract A plasma assay method for trazodone and a 2 H 4 analogue is described which uses gas chromatography—electron-impact selected-ion monitoring mass spectrometry. Etoperidone is used as an internal standard. The analytes are extracted from basic medium into n -butyl chloride, then back extracted into aqueous 0.1 M hydrochloric acid. The aqueous layer is made basic and re-extracted with n -butyl chloride. The solvent is reduced under nitrogen at 35°C and the residue is redissolved in toluene for gas chromatographic—mass spectrometric analysis. The ions monitored are m / z 231, 235, and 225 for trazodone, [ 2 H 4 ]trazodone and etoperidone, respectively. Quantitation is in the range 40–1000 ng/ml with acceptable precision and accuracy. The method is suitable for biopharmaceutical studies.