10Seger C, Godejohann M,Tseng LH, et al. LC-DAD-MS/SPE-NMR hyphenation. A tool for the analysis of pharmaceultically used plant extracts : identificat of is obaric iridoid glycoside regioisomers from Harpaaoohvtum procumbens. Anal Chem.2005.77:878-895.