A method to quantify the toxic pyrrolizidine alkaloids (PAs) in coltsfoot, Tussilago farfara L., by capillary electrophoresis was established using external and internal standardisation, The method is very sensitive and allows the quantification of amounts less than 0.5 ppm of senkirkine and senecionine in the drug. For sample preparation of the plant extracts, various extraction procedures were tested: the best method of extraction of the drug was by refluxing for 15 min with 50% methanol acidified with citric acid to pH 2-3. Final purification of the extracts was performed by solid phase extraction on diol-phase cartridges. The fast and exhaustive extraction of the alkaloids is the main advantage of the new method, which replaces the time consuming Soxhlet extraction. Owing to the high sensitivity and short analysis time, capillary electrophoresis is confirmed as an excellent complementary method in the quantification of toxic PAs in Folium Farfarae. Copyright (C) 2000 John Wiley & Sons, Ltd.
