Methanol hplc gradient grade

Methanol (HPLC gradient grade), ethanol, and tetrachloroethylene (synthesis grade) were purchased from Scharlab (Barcelona, Spain). CuSO₄·7H₂O, phenylisothiocyanate (PITC), 2,4,6-tri(2-pyridyl)-triazine (TPTZ), neocuproine, and DPPH were supplied by Sigma-Aldrich (St. Louis, MO, USA). Triethylamine (TEA), hydrochloric acid (37%), sodium acetate, glacial acetic acid, Fe₃Cl·6H₂O and FeSO₄·7H₂O, trichloroacetic acid (TCA), butylated hydroxytoluene (BHT), and 2-thiobarbituric acid (TBA) (analysis quality) were supplied by Panreac (Barcelona, Spain). Formic acid (synthesis grade) and amino acid standards Glu, His, Met, arginine (Arg), aspartic acid (Asp), lysine (Lys), proline (Pro), valine (Val), isoleucine (Ile), and phenylalanine (Phe) were provided by Merck (Darmstadt, Germany). Polyphenol standards were supplied as follows: gallic acid (GAL), protocatechuic acid (PCA), p-coumaric acid (COU), ferulic acid (FA), catechin (CAT), vanillic acid (VAN), epicatechin (ECAT), syringic acid (SYR), and Trolox (TR) by Sigma-Aldrich Chemie (Steinheim, Germany); rutin (RU) and gentisic acid (GA) by Merck (Darmstadt, Germany). Ultrapure water was obtained from a Milli-Q system from Millipore (Bedford, MA, USA).

Methanol (HPLC gradient grade) and tetrachloroethylene (synthesis grade) were purchased from Scharlab (Barcelona, Spain). Triethylamine (analysis quality) and phenylisothiocyanate (PITC) of reagent grade were supplied by Panreac (Barcelona, Spain); 1,1-diphenyl-2-picrylhydrazyl (DPPH), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and anthrone (reagent grade) were supplied by Sigma-Aldrich (St. Louis, MO, USA). Formic acid (synthesis grade) and amino acids (aspartic acid, glutamic acid, histidine, arginine, proline, valine, lysine, methionine, isoleucine, and phenylalanine) were provided by Merck (Darmstadt, Germany). Phenolic compounds were supplied as follows: gallic acid, protocatechuic acid, (−) epicatechin, ferulic acid, p-coumaric acid, vanillic acid, syringic acid, and (+) catechin by Sigma–Aldrich Chemie (Steinheim, Germany), and rutin and gentisic acid by Merck (Darmstadt, Germany). Ultrapure water was obtained from a Milli-Q system from Millipore (Bedford, MA, USA).

Methanol (HPLC gradient grade), ethanol and tetrachloroethylene (synthesis grade) were purchased from Scharlab (Barcelona, Spain), D-glucose (Glc), m-hydroxyphenyl, CuSO₄·7H₂O, DPPH, 2,4,6-tri(2-pyridyl)-triazine (TPTZ), neocuproine (of reagent grade), pyrocatechol violet (PV) and Trolox (TR) were supplied by Sigma-Aldrich (St. Louis, MO, USA). Formic acid (synthesis grade), Fe₃Cl·6H₂O and FeSO₄·7H₂O were supplied by Panreac (Barcelona, Spain). Ultrapure water was obtained from a Milli-Q system from Millipore (Bedford, MA, USA).
Polyphenol standards were supplied as follows: gallic acid (GAL), protocatechuic acid (PCA), p-coumaric acid (COU), ferulic acid (FA), catechin (CAT), vanillic acid (VAN), epicatechin (ECAT), syringic acid (SYR) and by Sigma–Aldrich Chemie (Steinheim, Germany); rutin (RU) and gentisic acid (GA) by Merck (Darmstadt, Germany).