On-line characterisation of apple polyphenols by high performance liquid chromatography coupled with mass spectrometry and ultraviolet absorbance detection

ALONSO-SALCES, R. M.; NDJOKO, K.; QUEIROZ, E. F.; IOSET, J. R.; HOSTETTMANN, K.; BERRUETA, L. A.; GALLO, B.; VICENTE, F.

Salamanca (España)

Conferencia; EUROANALYSIS XIII, European Conference of Analytical Chemistry; 2004

Sociedad Española de Química Analítica (SEQA), Dpto de Química Analítica, Nutrición y Bromatología de la Universidad de Salamanca, y Federation of European Chemical Societies Division of Analytical Chemistry (FECS)

Apple polyphenols were characterised by means of hyphenated techniques suchas HPLC coupled to UV photodiode array detection (LC -DAD) and to massspectrometry (LC-MS). LC-MS using atmospheric pressure ionisation (APCI) inthe positive ion mode provided the molecular weight, the number of hydroxylgroups, the number of sugars and an idea about the substitution pattern of thepolyphenols. LC-DAD with postcolumn addition of UV shift reagents affordedprecise structural information on the position of the free hydroxyl groups in thepolyphenol ic nucleus.Five isorhamnetin glycosides, two hydroxyphloretin glycosides and quercetinaglycone were reported in apple peel for the first time. Postcolumn addition of UVshift reagent in LC-DAD analysis permitted to confirm that the formers wereisorhamnetin glycosides and not their isomeric glycosides of rhamnetin.Moreover, isorhamnetin -3-0-rhamnoglucoside was identified unambiguously bycomparison with its standard. These results are considerably relevant not onlyfrom a chemotaxonomic point of view, but also in the authenticity control of fruitderived products in order to detect fraudulent admixtures.