Ultimate 3000 series system

The LC analysis was performed using Ultimate 3000 series system (Dionex, Idstein, Germany) equipped with dual low-pressure gradient pump with vacuum degasser, an autosampler, a column compartment, and a diode array detector coupled with Amazon SL ion trap mass spectrometer (Bruker Daltonik GmbH, Bremen, Germany). The separation of compounds in the analyzed extract was carried out with Kinetex XB-C₁₈ analytical column (100 mm × 2.1 mm × 1.9 µm), Phenomenex (Torrance, CA, USA). Column temperature was maintained at 25 °C. Elution was conducted using mobile phase A (0.1% HCOOH in deionized water) and mobile phase B (0.1% HCOOH in acetonitrile) with a two-step gradient as follows: 0 min 1% B, 60 min 26% B and finally 90 min 95% B. The flow rate was set to 0.300 mL/min. Five µL of each sample was introduced to the column by the autosampler. UV-vis spectra were recorded in the range of 190–450 nm. Chromatograms were acquired at 254 nm. The eluate was introduced directly into mass spectrometer. The ion trap mass spectrometer was equipped with ESI interface. The parameters for ESI source were set as follows: nebulizer pressure 40 psi; dry gas flow 9 L/min; dry temperature 300 °C; and capillary voltage 4.5 kV. Analysis was carried out using a scan from m/z 70–2,200. Compounds were analyzed in negative ion mode. The MS² fragmentations were performed using Smart Frag mode.