|ENGSTROM, MARCIA - University Of Turku|
|PALIJARVI, MAIIJA - University Of Turku|
|FRYGANAS, CHRISTOS - University Of Reading|
|MUELLER-HARVEY, IRENE - University Of Reading|
|SALMINEN, JUHA-PEKKA - University Of Turku|
Submitted to: International Conference of Polyphenols
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2014
Publication Date: 9/2/2014
Citation: Engstrom, M., Palijarvi, M., Fryganas, C., Grabber, J.H., Mueller-Harvey, I., Salminen, J. 2014. Rapid qualitative and quantitative analysis of proanthocyanidin oligomers and polymers by UPLC-MS/MS [abstract]. International Conference of Polyphenols. p. 95-96.
Technical Abstract: Proanthocyanidins (PAs) are a structurally complex and bioactive group of tannins. Detailed analysis of PA concentration, composition, and structure typically requires the use of one or more time-consuming analytical methods. For example, the commonly employed thiolysis and phloroglucinolysis methods for characterizing PAs include a prolonged depolymerization step prior to HPLC analysis. However, recent developments in ultra-performance liquid chromatography combined with a mass spectrometry (UPLC-MS/MS), provide new avenues for rapidly characterizing the chemistry of PAs. We developed a rapid UPLC-MS/MS method for the qualitative and quantitative analysis of PAs directly from crude plant extracts. The method utilizes a range of cone voltages to achieve the depolymerization of PA oligomers and polymers in the ion source. The resulting depolymerization products are further fragmented in the collision cell to enable their selective detection. Instead of a time-consuming degradation step, as required by thiolysis or phloroglucinolysis, the present method utilizes rapid in-source fragmentation of UPLC-separated PA molecules by cone voltages optimized for terminal and extension units of procyanidins (PC) and prodelphinidins (PD), which are the most common types of PAs. The acquired data enables (1) quantification of total PA, PC, and PD concentrations, (2) determination of the PC/PD ratios, and (3) estimation of mean degree of polymerization (mDP) of PAs. Furthermore, since PA fragmentation takes place after the chromatographic step, the method permits the characterization of PA composition and mDP throughout the chromatographic hump that is typically produced by larger PA polymers. All this is achieved within a 10- minute period of analysis, which makes our method a significant addition to the chemistry tools currently available for qualitative and quantitative characterization of PAs in plant extracts.