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Intact glucosinolate analysis in plant extracts by programmed cone voltage electrospray LC/MS: performance and
Fred A Mellon1, Richard N Bennett, Birgit Holst
1Institute of Food Research, Norwich Research Park, Colney, Norwich, United Kingdom. fred.mellon@bbsrc.ac.uk
Analytical Biochemistry
|June 19, 2002
Summary
A new liquid chromatography-mass spectrometry (LC/MS) method accurately identifies glucosinolates in plants. This sensitive technique uses programmed cone voltage fragmentation for reliable detection in plant extracts.
Area of Science:
- Analytical Chemistry
- Plant Biochemistry
- Mass Spectrometry
Background:
- Glucosinolates are crucial plant compounds with diverse biological activities.
- Accurate identification of glucosinolates in complex plant matrices is challenging.
- Existing LC/MS/MS methods may lack the required sensitivity or selectivity for comprehensive analysis.
Purpose of the Study:
- To develop a highly sensitive and specific LC/MS method for identifying all structural classes of glucosinolates.
- To establish a robust and reliable analytical technique for crude plant extracts.
- To compare the performance of the developed method against established LC/MS/MS techniques.
Main Methods:
- Utilized negative ion electrospray LC/MS.
- Employed programmed cone voltage fragmentation to generate characteristic m/z 96 and 97 ions.
- Analyzed abundance ratios of m/z 96 and 97 ions (1:2-1:4) for identification.
- Examined full-scan mass spectra for rapid and confident glucosinolate identification.
- Assessed detection limits in the low nanogram range.
Main Results:
- The method achieved simultaneous maxima for m/z 96 and 97 ions, enabling rapid glucosinolate identification.
- Programmed cone voltage fragmentation enhanced characteristic ions while preserving the [M - H]- ion and sulfur isotope peaks.
- Detection limits were in the low nanogram range for full-scan spectra.
- The programmed cone voltage method demonstrated superior sensitivity and selectivity compared to LC/MS/MS techniques (product ion, precursor ion, constant neutral loss scans).
- The methodology proved robust and reliable across various plant extracts.
Conclusions:
- The developed negative ion electrospray LC/MS method is comprehensive, sensitive, and highly specific for identifying all glucosinolate structural classes.
- Programmed cone voltage fragmentation offers an advantageous approach for glucosinolate analysis in crude plant extracts.
- This technique provides a reliable and superior alternative to existing LC/MS/MS methods for glucosinolate profiling.