2.2.2. Ascorbic acid quantification in orange juice
The ascorbic acid concentration was quantified with the HPLC
method as described by the procedure from TOSOH Bioscience
(2011) for the HPLC column. Single solvent system with acetonitrile
in water (1% v/v) þ 0.1% TFA was used for running the sample
for 10 min with a 10 mL injection volume at a flow rate of 1 mL/min.
The elution peaks were detected at 280 nm and a calibration curve
was prepared using ascorbic acid standard obtained from Sigma (St.
Louis, MO). The equation to calculate the concentration of ascorbic
acid (mg/L) is: