2. Materials and method 2.1. Reagents, solvents, and chemicals Authentic polyphenol reference standards (n=90) were deployed for identification and (semi-)quantitation purposes. The commercial sources and purity of the reference standards and the used solvents are listed in Table .1. The standards were prepared with methanol to create stock solutions and working mixtures at various concentrations to spike the samples and create calibration curves (Table .2).