Abstract: Guan-fu base A(GFA), a new antiarrhythmic alkaloid with a structure of C20-diterpenoid could react rapidly and quantitatively with trifluoroacetic anhydride (TFAA) to produce GFA-TFAA of which the structure was identified by GC-MSD. There was a wide linear range of the GC-ECD method from 10 to 20000 ng/ml (r = 0.9984). The average recovery of GFA from the spiked plasma was 97.52%. The coefficients of variation of within-day and between-day were less than 7% and 9%, respectively. The method was used in the preclinical experiment of pharmacology of GFA and the results showed that GFA concentrations in rabbits' plasma within 6 hours after the administration ranged from 0.338±0.014 to 13.459±5.393 μg/ml for dosage 10mg/kg, from 0.133±0.038 to 2.546±0.480 μg/ml for dosage 2 mg/kg and from 45.25±10.34 to 535.86±24.36 ng/ml for dosage 0.4 mg/kg.

Key words: Guan-fu base A (GFA), GC-ECD, Trifluoroacetic anhydride (TFAA), Derivatization, Plasma concentration