Injection volume
was fixed at 20 mL for all trials. Analyses were carried out on a
Shimadzu LC-10 HPLC system (Columbia, MD, USA), consisting of
10 LC-VP pump, CTO-10AS VP column oven, with SPD-M20A diode
array detector, SCL-10A VP interface, and Class VP software. Aminex
HPX-87H column (300 7.8 mm) (BioRad, Hercules, CA, USA)
maintained at 35 C was used for the analysis