Octa decylsilane c18

Standards of gallic acid (99%), 3-hydroxytyrosol (99.5%), (−)- gallocatechin (≥98%), caftaric acid (≥97%), (−)-epigallocatechin (≥95%), (+)-catechin (≥99%), (−)-epicatechin (≥95%), (−)- epigallocatechin gallate (≥95%), caffeic acid (99%), syringic acid (≥95%), coumaric acid (99%), ferulic acid (≥99%), piceatannol (99%), trans-resveratrol (≥99%), quercetin hydrate (95%), cinnamic acid (99%), quercetin 3-b-D-glucoside (≥90%), kaempferol-3-glucoside (≥99%) and malvidin-3-O- glucoside chloride (≥95%) were purchased from Sigma–Aldrich. The standard of 2-(4-hydroxyphenyl) ethanol (tyrosol) (≥99.5%) was obtained from Fluka (Buchs, Switzerland). Stock solutions of the above mentioned compounds were prepared in methanol at concentration levels of 1000 µgm l⁻¹. Calibration standards were dissolved in the initial mobile phase of each method (LMWP or anthocyanins, respectively). HPLC-grade Acetonitrile (MeCN) and formic acid (FA) were acquired from Mallinckrodt Baker (Inc. Phillipsburg, NJ, USA). Primary-secondary amine (PSA) and octa- decylsilane (C₁₈) were both obtained from Waters (Milford, MA, USA). Reagent grade NaCl, anhydrous Na₂CO₃, anhydrous MgSO₄ and anhydrous CaCl₂ were purchased from Sigma–Aldrich. Ultrapure water was obtained from a Milli-Q system (Millipore, Billerica, MA, USA).

Chlorothalonil (99.5% purity) was purchased from Sigma-Aldrich (Buchs, Switzerland), and its physicochemical characteristics are listed in Table 1. HPLC-grade acetonitrile was obtained from Merck (Darmstadt, Germany). Formic acid was obtained from Daejung (Siheung, Republic of Korea). QuEChERS salt extraction kits (Original, EN 15662, AOAC 2007.01) were purchased from Chromatific (Heidenrod, Germany). Primary secondary amine (PSA) was purchased from Agilent Technologies (Santa Clara, CA, USA), and octadecylsilane (C₁₈) and graphitized carbon black (GCB) were purchased from Waters (Leinster, Ireland). The polytetrafluoroethylene syringe filters (PTFE, 0.45 µm pore size) were purchased from Thermo Fisher Scientific (Waltham, MA, USA).