Qualitative and quantitative analysis of iridoid glycosides in the flower buds of Lonicera species by capillary high performance liquid chromatography coupled with mass spectrometric detector

摘要

A highly sensitive and specific method,based on capillary high performances liquid chromatography coupled with single quadrupole mass spectrometry using electrospray ionization(capillary HPLC-ESI/MS),is proposed for the identification and quantification of iridoid glycosides in the flower buds of five Lonicera species.A Zorbax SB-C18(0.3 mm X 150 mm,5 mum)capillary column and a gradient elution with methanol-acetonitrile-aqueous acetate acid were utilized.The most intensive electrospray ionisation signals were found in the negative ion spectra owing to CH_3COO~-adducts.Eight iridoid glycosides derived from the flower buds of Lonicera species were analyzed by mass spectrometry;swero-side(IG1),7-O-ethyl sweroside(IG2),7-epi vogeloside(IG3),secoxyloganin(IG4),secoxyloganin 7-butyl ester(IG5),dimethyl-secologanoside(IG6),centauroside(IG7),and loganin(IG8)using combined information on retention time,the molecular ion mass and fragment ion masses.Detection limits were lower than 1.9 ng/mL in selected ion monitoring(SIM)mode and all calibration curves showed good linear regression(r~2> 0.9938)within test ranges.The validated method was successfully applied to analyze eight iridoid glycosides in the flower buds of five Lonicera species and provided a new basis of assessment on quality of Flos Lonicerae.