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Capillary gas chromatographic—mass spectrometric determination of stable isotopically labelled and unlabelled theophylline in serum and urine and of 1,3-dimethyluric acid in urine

1989; Elsevier BV; Volume: 494; Linguagem: Inglês

10.1016/s0378-4347(00)82660-2

1872-812X

Yasuji Kasuya, Takashi Furuta, Hirotaka Shimota,

Cancer therapeutics and mechanisms

A capillary gas chromatographic—mass spectrometric method for the determination of [13C, 15N2]theophylline and unlabelled theophylline (TP) and of 1,3-dimethyluric acid (1,3-DMU), a major metabolite of TP, is described. TP and the metabolite were extracted separately from serum or urine, purified by high-performance liquid chromatography and converted into alkyl derivatives (monoethyl-TP and dibutyl-1,3-DMU). The internal standards used for the respective determinations were [2H6]TP and [2H6]1,3-DMU. Detection was performed by monitoring the molecular ions of the alkyl derivatives. The method needed no complex corrections for contributions and provides good accuracy and precision.