An integrated high resolution mass spectrometric and informatics approach for the rapid identification of phenolics in plant extract

An integrated approach based on high resolution MS analysis (orbitrap), database (db) searching and MS/MS fragmentation prediction for the rapid identification of plant phenols is reported. The approach was firstly validated by using a mixture of phenolic standards (phenolic acids, flavones, flavonols, flavanones, flavanols, isoflavones). In particular, the integrated approach consists of the following steps: (1) LC–ESI-MS/MS analysis in data dependent scan mode using an orbitrap mass analyzer (resolution 60,000; positive ion-mode, ESI source); (2) searching the experimental monoisotopic masses (tolerance 1 ppm) in plant phenols databases; (3) filtering the entries on the basis of the phenol class to which the unknown belongs, as determined on the basis of the UV spectrum. Final identification is achieved by matching the isotopic pattern and by MS/MS fragmentation studies. In particular, experimental MS/MS fragments are matched with those predicted by a commercially available software. The method was then successfully applied for the rapid identification of phenolics contained in an EtOH extract of Angelica keiskei.