SPE (Solid Phase Extraction)
lime juice hand-squeezed in laboratory, centrifuged and filtered through a 0.45 μm nylon filter disc (Acrodisc)
Ascentis Express C18, 5 cm x 4.6 mm I.D., 2.7 μm particles (53826-U)
[A] water/formic acid (99.9:0.1); [B] water/acetonitrile/isopropanol/formic acid (39.9:20:40:0.1)
10% B for 3 min; 10 to 34% B in 30 min; 34 to 100% B in 1 min; held at 100% B for 6 min; 100 to10% B in 1 min
0.8 mL/min
ambient
PDA: 190–370 nm; chromatogram extracted at 283 nm
ESI-MS: mass spectral range, 250-700 m/z; interval, 0.5 s; scan speed, 938 amu/s; nebulizing gas (N2) flow, 1.5 L/min; (interface temperature, 350 °C; heat block, 300 °C; desolvation line (DL) temperature, 300 °C; DL voltage, 34 V; probe voltage, +4.5 kV; Qarray voltage, 1.0 V; RF voltage, 90 V; detection gain, 1.05 kV)
2 μL
Flavonoids are polyphenolic compounds ubiquitous in nature and classified, according to their chemical structure, into flavonols, flavones, flavanones, isoflavones, catechins, anthocyanidins and chalcones. They are widely present in fruits, vegetables, leaves, nuts, seeds, bark and beverages (tea, coffee, beer, wine and fruit drinks).
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