The analyses were performed by using a Shimadzu liquid chromatograph (Kyoto, Japan) equipped with an SIL-20 auto sampler, an SPD-M10A VP PDA photodiode array detector and Class VP 7.3 chromatography software. A C18 reversed phase column (Phenomenex Kinetex®2.6 μm, 100A, 100 × 4.60mmi.d.)was used as the solid phase