Acetonitrile and acetic acid (Merk KGaA, Darmstadt, Germany) were of LC-MS grade. A Genie Water System (RephiLe Bioscience Ltd., Shanghai, China) was used to obtain ultrapure water. Phloroglucinol, gallic acid, protocatechuic acid, gentisic acid, (-)-catechin, 4-hydroxybenzoic acid, vanillic acid, epicatechin, syringic acid, p-coumaric acid, ferulic acid, myricitrin, absisic acid, trans-cinnamic acid, luteolin, and naringenin were acquired from Extrasynthese (Genay, France).