HPLC-DAD-ESI/MS analysis of the phenolics and flavonoids

A Hewlett-Packard 1100 chromatograph (Agilent Technologies) equipped with a quaternary pump and a diode array detector (DAD) was used to evaluate the semi-purified plant extracts. An HP Chem Station (ver. A.05.04) data processing station was connected to the machine. A Waters Spherisorb S3 ODS-2 C18, 3 µm (4.6 mm × 150 mm) column thermostated at 35 °C was used. 0.1% formic acid (A) and acetonitrile (B) were the two solvents employed in the gradient elution protocol of the sample components as follows: 5 min (10% B to 15% B), 5 min (15–25% B), 10 min (25–35% B), then the last 10 min was followed by the isocratic system of 50% B. The column flow rate was 0.5 ml/min. A mass spectrometer (MS) linked to an HPLC system through the DAD cell output and the DAD were used for double online detection with the recommended wavelengths of 280 nm and 370 nm. Authentic samples of phenolic acids and flavonoids were used in the identification of the extract constituents through a comparison of their retention times (RT); these constituents were assigned by ASTERISK (*) in Table 4.

LC-MS-MS analysis of Arbutus pavarii Pampan fruits extract.

An ESI source, a triple quadrupole-ion trap mass analyser, and an API 3200 Qtrap (Applied Biosystems, Darmstadt, Germany) were used for the MS observation process. Analyst 5.1 was used to operate the apparatus according to the parameters mentioned in the literature.³⁶