The LC-MS/MS system described above was also used for
anthocyanin analysis. A Gemini C18 110A column with 5 mm particle
size (150 mm 4.60 mm) was used to separate the anthocyanins.
The mobile phase consisted of A (0.5% formic acid in water) and B
(0.5% formic acid in methanol) at a flow rate of 0.5 mL/min. The
gradient was set as follows: 0e5 min, 10% B; 5e8 min, 10e15% B; 8e
13 min, 15e20% B; 13e18 min, 20e25% B; 18e25 min, 25e30% B;
25e30 min, 30e35% B; 30e35 min, 35e50% B; 35e40 min, 50e60%
B; 40e45 min 60e95% B; 45e50 min, 95e10% B; 50e58 min 10% B.
The anthocyanins were detected at a wavelength of 520 nm. The QTOF-MS
was calibrated using sodium iodide for positive mode
through the mass range of 100e1500. MS parameters were set as
follows: capillary voltage, 2100 V; sample cone voltage, 35 V;
source temperature, 120 C; desolvation temperature, 250 C;
desolvation gas (nitrogen gas) flow rate, 900 L/hr. The MS/MS
spectra were acquired by using collision energy of 30 V.