Samples (20 μL) were separated at room temperature
on a Waters Spherisorb C18 column (250×4.6 mm id; 5 μm particle
size) using a solvent of 0.1% oxalic acid at a flow rate of 1.0 mLmin−1.
The amount of ascorbic acid was calculated from absorbance values
at 243 nm, using authentic ascorbic acid as a standard.