LC-HRMS and LC-MS/MS analysis of artemisinin and artemisinic acid

Artemisinin is a sesquiterpene lactone with a peroxide bridge. It is an effective medicine against drug-resistant Plasmodium falciparum, the malarial agent. Natural sources of artemisinin are the bark of Chinchoa species and Artemisia annua (known as sweet or annual wormwood or simply artemisia).

Analysis of artemisinin using HPLC-UV is possible only after derivatization. Artemisinin can not be detected unequivocally using gas chromatography. Only thermal decomposition products of artemisinin (it decomposes in the injector) may be observed in GC analyses. High-resolution mass spectrometry or LC-MS/MS covers both, unambiguous identification and quantification, goals.

Instrumental: 1) Orbitrap Discovery hybrid FT mass spectrometer coupled with Accela UPLC (Thermo Scientific) equipped with positive APCI ion source; data was acquired in m/z 150-1200 Da scan range. Chromatographic separations were carried out using the Gemini Hexyl-Phenyl column (2×150 mm, 3µ particle size, Phenomenex) using a linear gradient of methanol/water (with 0.1% acetic acid).

2) Agilent LC-MS/MS system which consisted of triple-quadrupole 6410B coupled with 1200 Rapid-LC (binary pump, autosampler, column compartment). Chromatographic separations were carried out using the Acclaim C18 column (3×250 mm, 3µ particle size, Dionex) using a linear gradient of acetonitrile/water (with 0.1% acetic acid). Data were acquired in MRM mode. Artemisinin-D3  was an internal standard for artemisinin in positive ESI while gemfibrozil-D6 was used as IS for artemisinic acid in negative ESI mode.

The results of this application were published in,

"Generation of the potent anti-malarial drug artemisinin in tobacco" December 2011, Nature Biotechnology, 29(12):1072-4.