Screening of glycoside isomers in P. scrophulariiflora using ionic liquid-based ultrasonic-assisted extraction and ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry
Article first published online: 15 FEB 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 26, Issue 7, pages 740–748, 15 April 2012
How to Cite
Cao, X., Qiao, J., Wang, L., Ye, X., Zheng, L., Jiang, N. and Mo, W. (2012), Screening of glycoside isomers in P. scrophulariiflora using ionic liquid-based ultrasonic-assisted extraction and ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry. Rapid Commun. Mass Spectrom., 26: 740–748. doi: 10.1002/rcm.6158
- Issue published online: 15 FEB 2012
- Article first published online: 15 FEB 2012
- Manuscript Revised: 5 JAN 2012
- Manuscript Accepted: 5 JAN 2012
- Manuscript Received: 28 SEP 2011
A powerful ionic liquid-based ultrasonic-assisted extraction (ILUAE) method combined with ultra-performance liquid chromatography coupled to electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC/ESI-QTOFMSn) was employed in the rapid simultaneous screening of iridoid glycosides, phenylethanoid glycosides, and cucurbitacin glycosides from P. scrophulariiflora. The ILUAE procedure was optimized over several ultrasonic parameters, including the ultrasonic power, concentration of the ionic liquid, and solid–liquid ratio. A comparison with conventional heat-reflux extraction and regular UAE demonstrated that the optimized approach yielded a high extraction efficiency (Picroside I, 2.84%; Picroside II, 3.57%; 6-O-E-feruloyl catalpol, 2.20%) within a short extraction time of 30 min. Negative ion mode ESI-QTOFMS2 analysis of the fragmentation reactions of the [M–H]– ions was conducted to characterize the diagnostic ions related to the glycosyl moieties, aglycone units, and the type and substituted position of the ester groups. Interestingly, the positional isomers of the iridoid glycosides could be easily discriminated based on the characteristic ions. A total of 15 glycosides, including three groups of iridoid glycoside isomers and two groups of phenylethanoid glycoside isomers, were conveniently identified within 13.5 min. Moreover, 6'-O-vanilloyl catalpol was identified in P. scrophulariiflora for the first time. The method developed here was further validated by measuring the recovery, correlation coefficient (R2), and reproducibility (RSD, n = 5) of three iridoid glycosides: 89.60%–109.02%, 0.9991–0.9998, and 0.93%–1.44%, respectively. This study demonstrated the capabilities of ILUAE combined with UPLC/ESI-QTOFMSn for the rapid screening of glycosides in P. scrophulariiflora. This method offers an approach to similar studies on other natural plants. Copyright © 2012 John Wiley & Sons, Ltd.