HPLC-ESI-TOF-MS Analysis of GCE, eGCE and Tannic Acid

GCE, eGCE and tannic acid were analyzed by high performance liquid chromatography coupled to electrospray ionization-time of flight-mass spectrometry (HPLC-ESI-TOF-MS) [19 (link)], a tandem system. The Agilent 1200 series HPLC consisted of a model G1315D diode array detector (DAD), a G1312B binary Pump, a G1379B vacuum degasser, a G1367C auto-sampler and a G1316B column heater. The concentration of the testing solution was 1mg/mL, and the injection volume was 5 μL. Gradient elution HPLC was applied at a flow rate of 0.4 mL/min with detection at 270 nm. Two solvents were used for the mobile phase: (A) 0.1% formic acid and 10 mM ammonium formate (pH3.0), (B) acetonitrile. Compounds were separated using the following gradient: 0-5 min, 5% B; 5-8 min, 20% B; 20-30 min, 30% B; 30-40 min, 20% B; 40.0-40.1 min, 5% B. The separation of components in GCE was performed on an Agilent column (Poroshell 120 SB-C18, 150mm × 4.6mm, particle size 2.7μm) at 40 °C.
The time of flight (TOF) mass detector (G1969A, Agilent, US) was equipped with electrospray ionization (ESI) interface. The ESI voltage was 3.5 kV, and a mass range of 50-3000 m/z was scanned in negative full scan mode. Data processing was performed on Agilent Mass Hunter (v.B.01.04) software.