O phthalaldehyde opa

Biogenic amine standards (histamine dihydrochloride (HIS), tryptamine hydrochloride (TRP), 2-phenylethylamine (2-PHE), putrescine dihydrochloride (PUT), cadaverine dihydrochloride (CAD), tyramine hydrochloride (TYR), spermidine trihydrochloride (SPD), and spermine tetrahydrochloride (SPM)) and dansyl chloride were obtained from Sigma-Aldrich Chemical Co. (St. Louis, MO, USA). Perchloric acid, 25% ammonium hydroxide solution, sodium hydroxide sodium hydrogen carbonate, and diethyl ether were acquired from Daejung Chemical Co. (Siheung, Korea). Acetone and acetonitrile (High-performance liquid chromatography (HPLC) grade) were purchased from Tedia Co. (Fairfield, OH, USA). Compound mixtures of amino acids, borate buffer, o-phthalaldehyde (OPA) and 9-fluorenylmethoxycarbonyl chloride (FMOC-Cl) were obtained from Agilent Technologies (Andover, MA, USA).

Chromatographically pure acetonitrile and acetic acid was purchased from Thermo Fisher (Waltham, MA, USA). Catechins (C), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), epigallocatechin gallate (ECG), gallocatechin gallate (GCG), epigallocatechin-3-O-gallate (EGCG), procyanidin B1, procyanidin C1, kaempferitrin, rutin, isoquercetin, myricetin-3-O-galactoside, myricetin-3-O-rutinoside, galloylglucose, gallic acid, cinnamic acid, chlorogenic acid, shikimic acid, p-coumaric acid, quinic acid, pyrogallic acid, theogallin, strictinin, theanine, theobromine, ethyl gallate, tannic acid, caffeine, L-sodium glutamate, and D-glucose were purchased from Yuanye (Shanghai, China). Quercetin, myricetin, kaempferol, and kaempferol-3-O-glucoside were purchased from Shanghai Zzstandard (Shanghai, China). Amino acid mixture standard reagent, borate buffer solution, o-phthalaldehyde (OPA), and 9-fluorene methyl chloroformate (FMOC) were purchased from Agilent Technology (Santa Clara, CA, USA). n-Hexane was purchased from Thermo Fisher (Waltham, MA, USA). 2-Methyl-3-heptanone and n-alkanes (C₇–C₃₀) were purchased from Sigma (St. Louis, MO, USA).