Determination of Aconitum alkaloids in the tubers of Aconitum japonicum using gas chromatography/selected ion monitoring.

A rapid, specific and precise method using GC/SIM was applied to separate and quantify Aconitum alkaloids in Aconitum tubers. The TMS derivatives of each alkaloid produced a well defined peak on selected ion recording (SIR). Good linear response over the range of 100 pg - 7.5 ng was demonstrated for each alkaloid. Furthermore, we investigated the changes in the contents of Aconitum alkaloids, i.e., hypaconitine, mesaconitine, aconitine, and jesaconitine, in Aconitum tubers paying special attention to the harvesting season. Mesaconitine had the highest value in all seasons. Mesaconitine and aconitine showed the highest value in the samples harvested in May 1991 while hypaconitine had the highest value among those harvested in December 1990. As to the total amount of the alkaloids, the highest value, 4190 microg/g, and the lowest value, 1881 microg/g, were observed in the samples harvested in May and September, respectively. GC/SIM was very useful for the determination of Aconitum alkaloids in the tubers.