[Methyl-D3]2hypericin as internal standard for quantification in human plasma

Piperopoulos, Georgios; Kiehne, Andrea; Ingendoh, Arnd; Zeller, Klaus-Peter
March 2003
Analytical & Bioanalytical Chemistry;Mar2003, Vol. 375 Issue 6, p744
Academic Journal
The multistep synthesis and negative ion-ESI fragmentation pattern of [methyl-D3]2hypericin (1-d6) is described. The application of 1-d6 as internal standard for the quantification of hypericin (1) in the ng mL-1 range in human plasma by isotope-dilution LC–MS is demonstrated. The hypericin-containing plasma samples are spiked with 1-d6, deproteinized and extracted with ethyl acetate. The extracts are injected into a HPLC–ESI–ion-trap system and the mass-separated negative ions from 1 and 1-d6 are analysed. From their intensities linear standard curves over the concentration range from 1 to 10 ng mL-1 are obtained. Accuracy, precision and recovery are discussed.


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