HPLC/ESI-MSn and ESI-MS studies on the Aconitum alkaloids in three Chinese medicinal herbs.

Aconitum lipo-alkaloids (LDAs) peaks in the previous HPLC studies have shown overlapping behavior, making it impossible to identify the total retention behavior of LDAs. The structural diversity of LDAs in Radix Aconiti, Radix Aconiti Kusnezoffii and Radix Aconiti Lateralis Preparata makes it difficult to synthesize and quantify each of them. Therefore, this study has been devoted to develop a HPLC/ESI-MS(n) method with good resolution of Aconitum alkaloids especially LDAs and then set up a fast ESI-MS SIM method to quantify the total contents of specific skeleton LDAs in the three herbs via in-source CID and the capability of mass separation. As a result, the retention behavior of LDAs was summarized based on an optimized chromatographic separation; 32 alkaloids from the three herbs of Aconitum genus were separated and identified according to their fragmentation pathways by using HPLC/ESI-MS(n). In addition, a fast quantitative analysis ESI-MS SIM method was successfully applied to the quantification of the total contents of specific skeleton LDAs in the three herbs.