E2695 connecting 2998 photodiode array detector system

Samples for catechin determination were treated as described for UPLC–Q–TOF/MS (KC et al., 2018 (link)). For free amino acid analysis, samples were derivatized as recommended by the waters AccQ Tag chemistry package. HPLC analysis was carried out using an e2695 connecting 2,998 photodiode array detector system (Waters Corp., Milford, MA, USA) injected with 10 or 25 μl of sample solutions for catechin or free amino acid, respectively. For catechins, distilled water with 2% formic acid was used as mobile phase A. Mobile phase B consisted of HPLC solvent Acetonitrile (ACN). The samples were eluted at column temperature 40 ± 1°C at a flow rate of 1 ml/min and monitored at 278 nm. Similarly, for amino acids, the AccQTag eluent from waters was used as mobile phase A. Mobile phase B was ACN, and the column temperature was set at 37 ± 2°C. The procedure was completed as prescribed in the AccQ Tag chemistry package instruction manual. Peaks of catechins were identified by comparing the retention times of the samples to those of authentic standards and amino acids were identified as prescribed in the manual.

Samples were assigned and extracted as for UPLC-Q-TOF/MS for catechin determination [7 (link)]. Free amino acid samples were analyzed as per the instructions provided by the waters AccQ.Tag chemistry package. HPLC analysis was carried out using an e2695 connecting 2998 photodiode array detector system (Waters) injected with 10 µL and 25 µL sample solutions for catechin and free amino acids, respectively. For catechins, distilled water with 2% formic acid was used as mobile phase A. Mobile phase B consisted of the HPLC solvent ACN. The samples were eluted at a column temperature of 40 ± 1 °C and a flow rate of 1 mL/min and monitored at 278 nm. Similarly, for amino acids, AccQ.Tag eluent from waters was used as mobile phase A. Mobile phase B was can, and the column temperature was set at 37 ± 2 °C. The remainder of the procedure followed the method prescribed in the AccQ. Tag chemistry package instruction manual. Peaks of catechins were identified by comparing sample retention time to those of authentic standards, and amino acid peaks were as prescribed in the manual.

Samples were assigned and extracted same as UPLC-Q-TOF/MS for catechin determination. For free amino acid analysis samples were derivatized as the instruction provided by waters AccQ.Tag chemistry package. HPLC analysis was carried out using an e2695 connecting 2998 photodiode array detector system (Waters) injected with 10 $\mathsf{\mu }$ L and 25 $\mathsf{\mu }$ L of sample solutions for catechin and free amino acid respectively. For catechins distilled water with 2% formic acid was used as mobile phase A. Mobile phase B consisted of HPLC solvent ACN (Sigma-Aldrich Co., St. Louis, MO, USA). The samples were eluted at column temperature 40 ± 1 ${}^{\circ }$ C at a flow rate of 1 mL/min and monitored at 278 nm. Similarly, for amino acid AccQ.Tag eluent from waters was used as mobile phase A. Mobile phase B was ACN and column temperature was set at 37 ± 2 ${}^{\circ }$ C. Rests of the procedure was followed as prescribed in AccQ. Tag chemistry package instruction manual. Peaks of catechins were identified by comparing the retention time of the sample to those of authentic standards and amino acids were as prescribed in the manual.