Identification and characterization of curcuminoids in turmeric using ultra-high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry

- This is the most comprehensive characterization of curcuminoids in turmeric so far.
- The keto and enol forms of curcuminoids in turmeric samples were confirmed.
- The false positive results were excluded by the positive and negative ESI-MS/MS.
- The fragmentation rules of all kinds of curcuminoids were fully summarized.

A three-step strategy was developed for systematic characterization of curcuminoids in turmeric. Based on UHPLC-QTOF-MS/MS analysis, 89 curcuminoids including 16 novel ones were identified in the turmeric samples using this approach. During the identification process, false positive results were excluded by combining the positive and negative ESI-MS/MS analyses. Moreover, the characterization of the keto and enol forms of type A, B and C curcuminoids was first discussed and they were clearly distinguished using negative ESI-MS/MS method with UV spectra analyses. The structures of detected curcuminoids were identified and rationalized in both ion modes. Additionally, the fragmentation behaviors of the 15 types of curcuminoids were clearly illustrated in this work, which will be helpful for detection and identification of corresponding trace curcuminoids in complex turmeric samples using UHPLC-QTOF-MS/MS methods.