DETERMINATION OF THE ANTIOXIDANT 3-TERT-BUTYL-4-HYDROXY-ANISOLE IN RAT PLASMA USING HIGH-RESOLUTION GAS CHROMATOGRAPHY-MASS SPECTROMETRY

A method is described for the determination of the antioxidant 3-tert-butyl-4-hydroxyanisole in rat plasma using high-resolution capillary gas chromatography-mass spectrometry with selective ion monitoring. Following the addition of the isomer 2-tert-butyl-4-hydroxyanisole, used as an internal standard, extraction was made with n-hexane and the extract derivatized with heptafluorobutyric anhydride. The gas chromatographic separation was carried out on a SE-52 fused silica capillary column and the derivatized 3-tert-butyl-4-hydroxyanisole and its isomer detected by recording the intensities of their common fragment ion at m/e 361. The sensitivity of the method allowed the antioxidant to be measured in 0.1-ml rat plasma samples down to a level of 10 ng/ml with a high degree of specificity and accuracy. The method was applied to a preliminary pharmacokinetic study in rats after oral dosage.