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Investigation of Isomeric Transformations of Chlorogenic Acid in Buffers and Biological Matrices by Ultra Performance Liquid Chromatography Coupled with Hybrid Quadrupole/Ion Mobility/Orthogonal Acceleration Time-of-flight Mass Spectrometry.
MedLine Citation:
PMID:  21942218     Owner:  NLM     Status:  Publisher    
Ultra performance liquid chromatography coupled with hybrid quadrupole/ion mobility/orthogonal acceleration time-of-flight (<i>oa</i>-TOF) mass spectrometry (UPLC-IM-MS) was used to study the isomeric transformations of <i>trans</i>-5-caffeoylquinic acid, an extremely active compound present in multiple vegetables, fruits, and beverages. The UPLC/<i>oa</i>-TOF MS results proved that in phosphate buffer (pH 7.4), plasma or urine sample, <i>trans</i>-5-caffeoylquinic acid first isomerizes to <i>trans</i>-4-caffeoylquinic acid, and then to <i>trans</i>-3-caffeoylquinic acid by intramolecular acyl migration. When exposed to UV light, <i>trans</i>-3-, -4-, and -5-caffeoylquinic acids undergo <i>cis/trans</i> isomerization to form <i>cis</i> isomers. The isomerization was solely dependent on the pH of the matrix, as well as the incubation temperature, and was independent of metabolic enzymes. UPLC-IM-MS results revealed that a reversible <i>cis/trans</i> isomerization of caffeoylquinic acids could also be induced by the electric field in an electrospray source. Thus, understanding the possible role of electric field-induced isomerization of caffeoylquinic acids may help lessen the confusion between gas phase phenomena and liquid state chemistry when applying IM-MS analysis. The comprehensive understanding of caffeoylquinic acid isomerization transformations is crucial for the appropriate handling of samples and interpretation of experimental data.
Cen Xie; Kate Yu; Dafang Zhong; Tao Yuan; Fei Ye; Joseph Andy Jarrell; Alan Millar; Xiaoyan Chen
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-9-25
Journal Detail:
Title:  Journal of agricultural and food chemistry     Volume:  -     ISSN:  1520-5118     ISO Abbreviation:  -     Publication Date:  2011 Sep 
Date Detail:
Created Date:  2011-9-27     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0374755     Medline TA:  J Agric Food Chem     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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