HPLC Analysis of Green Coffee Compounds

HPLC analysis was performed as described previously with slight modification [8 (link)]. Briefly, a 150 mm × 2.1 mm i.d., 4 μm, Nova-Pak C18 (Waters, Milford, MA) was used as the stationary phase to analyze the standards and green coffee samples. The samples were separated using a gradient condition; buffer A (10 mM phosphate, pH 5) for 0–5 min, a linear gradient from buffer A to buffer B (40% acetonitrile) for 5–45 min, and buffer B for 10 min (1 mL/min). The samples were injected by an autosampler into Alliance 2690 HPLC system (Waters, Milford, MA), and were monitored by CoulArray electrochemical detector with four electrode channels (ESA, Chelmsford, MA).