Classification of olive leaves and pulp extracts by comprehensive two-dimensional liquid chromatography of polyphenolic fingerprints.

The development of a new comprehensive two-dimensional liquid chromatographic method is described, to obtain the profiles of polyphenolic compounds present in olive (Olea europaea L.) leaves and pulps from different genetic origin. Optimisation of the stationary phase nature, particle size, column length and internal diameter, as well as other separation conditions, was performed. Along the study, three stationary phases (C18, PFP and phenyl) in the first dimension (1D), and five (C18, amide, cyano, phenyl and PFP) in the second dimension (2D) were combined to obtain the maximal number of resolved peaks. The optimised method successfully characterised the presence of 26and 29 common polyphenols in olive leaves and pulp extracts, respectively. Peak volume ratios were used to develop linear discriminant analysis models able to distinguish olive leaves and pulp extracts among seven cultivars from several Spanish regions. The results demonstrate that polyphenolic profiles were characteristic of each cultivar.