TY - JOUR
T1 - Time-of-flight accurate mass spectrometry identification of quinoline alkaloids in honey
AU - Rodríguez-Cabo, Tamara
AU - Moniruzzaman, Mohammed
AU - Rodríguez, Isaac
AU - Ramil, María
AU - Cela, Rafael
AU - Gan, Siew Hua
N1 - Funding Information:
This study has been supported by the Spanish Government and E.U. FEDER funds (project CTQ2012-33080), and also by the Xunta de Galicia (Excellence Research Groups Program). T.R.C. and M.M. acknowledge their contracts from the Spanish Ministry of Economy and Competitiveness and the Erasmus Mundus Experts II Program, respectively. We are also indebted to Prof. Huidobro and the Galician Association of Beekeepers for providing many of the samples used in this research.
Publisher Copyright:
© 2015 Springer-Verlag Berlin Heidelberg
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2015/6/4
Y1 - 2015/6/4
N2 - Time-of-flight accurate mass spectrometry (TOF-MS), following a previous chromatographic (gas or liquid chromatography) separation step, is applied to the identification and structural elucidation of quinoline-like alkaloids in honey. Both electron ionization (EI) MS and positive electrospray (ESI+) MS spectra afforded the molecular ions (M.+ and M+H+, respectively) of target compounds with mass errors below 5 mDa. Scan EI-MS and product ion scan ESI-MS/MS spectra permitted confirmation of the existence of a quinoline ring in the structures of the candidate compounds. Also, the observed fragmentation patterns were useful to discriminate between quinoline derivatives having the same empirical formula but different functionalities, such as aldoximes and amides. In the particular case of phenylquinolines, ESI-MS/MS spectra provided valuable clues regarding the position of the phenyl moiety attached to the quinoline ring. The aforementioned spectral information, combined with retention times matching, led to the identification of quinoline and five quinoline derivatives, substituted at carbon number 4, in honey samples. An isomer of phenyquinoline was also noticed; however, its exact structure could not be established. Liquid–liquid microextraction and gas chromatography (GC) TOF-MS were applied to the screening of the aforementioned compounds in a total of 62 honeys. Species displaying higher occurrence frequencies were 4-quinolinecarbonitrile, 4-quinolinecarboxaldehyde, 4-quinolinealdoxime, and the phenylquinoline isomer. The Pearson test revealed strong correlations among the first three compounds.
AB - Time-of-flight accurate mass spectrometry (TOF-MS), following a previous chromatographic (gas or liquid chromatography) separation step, is applied to the identification and structural elucidation of quinoline-like alkaloids in honey. Both electron ionization (EI) MS and positive electrospray (ESI+) MS spectra afforded the molecular ions (M.+ and M+H+, respectively) of target compounds with mass errors below 5 mDa. Scan EI-MS and product ion scan ESI-MS/MS spectra permitted confirmation of the existence of a quinoline ring in the structures of the candidate compounds. Also, the observed fragmentation patterns were useful to discriminate between quinoline derivatives having the same empirical formula but different functionalities, such as aldoximes and amides. In the particular case of phenylquinolines, ESI-MS/MS spectra provided valuable clues regarding the position of the phenyl moiety attached to the quinoline ring. The aforementioned spectral information, combined with retention times matching, led to the identification of quinoline and five quinoline derivatives, substituted at carbon number 4, in honey samples. An isomer of phenyquinoline was also noticed; however, its exact structure could not be established. Liquid–liquid microextraction and gas chromatography (GC) TOF-MS were applied to the screening of the aforementioned compounds in a total of 62 honeys. Species displaying higher occurrence frequencies were 4-quinolinecarbonitrile, 4-quinolinecarboxaldehyde, 4-quinolinealdoxime, and the phenylquinoline isomer. The Pearson test revealed strong correlations among the first three compounds.
KW - Alkaloids
KW - Honey
KW - Quinoline
KW - Time-of-flight mass spectrometry
UR - http://www.scopus.com/inward/record.url?scp=85028239090&partnerID=8YFLogxK
U2 - 10.1007/s00216-015-8791-2
DO - 10.1007/s00216-015-8791-2
M3 - Article
C2 - 26041455
AN - SCOPUS:85028239090
SN - 1618-2642
VL - 407
SP - 6159
EP - 6170
JO - Analytical and Bioanalytical Chemistry
JF - Analytical and Bioanalytical Chemistry
IS - 20
ER -