Determination of <i>Catharanthus roseus</i> alkaloids by high-performance liquid chromatography-isotope dilution thermospray-mass spectrometry

This paper describes a high-performance liquid chromatography-isotope dilution thermospray-mass spectrometry method for the determination of catharanthine, tabersonine, yohimbine and ajmalicine in cell culture samples of Catharanthus roseus. The use of deuterated analogues of the alkaloids as internal standards remarkably improved the precision of the analysis. The standard deviation between six repeated assays was close to or below 10% when the reference compounds were analyzed, but was about 10% higher, in most instances, when vincamine was used as the internal standard. The precision of this method was about 20% for biological extracts.