Application note: Determination of Pyrrolizidine Alkaloids in Tea using SFC-MS/MS

SFC-MS/MS method for high-sensitivity analysis of 34 PAs in commercial tea samples.

Pyrrolizidine alkaloids (PAs) are potentially carcinogenic plant metabolites. They occur mainly in plants of the Boraginaceae, Asteraceae and Fabaceae families. They contain a pyrrolizidine core and make up a large group of heterocyclic alkaloids mainly derived from the 4 Necin bases platynecine, retronecine, heliotridin and ontonecin. PAs are hepatotoxic if they carry a 1,2-double bond as well as an esterified side chain which is a structural prerequisite for their hepatic activation. Exposure to PAs in food, beverages or phytopharmaceuticals, is a possible long-term concern for human health. Based on available data the Panel on Contaminants in the Food Chain (CONTAM) have proposed a list of PAs to be monitored in foodstuffs.

Since some of the analytes are isomers that can’t be distinguished by different mass, they have to be separated chromatographically. LC-MS/MS is the standard method for determination of PAs. However, separation of these compounds often poses a challenge. SFC offers complementary chromatographic selectivity to RP-LC and an advantage for separation of stereoisomers, shown in the development of a separation method for determination of 34 PAs including 5 Lycopsamin and 2 Senecionin isomers.