High Performance Liquid Chromatography (HPLC): A Hewlett Packard (now Aijiren) series HPLC equipped with an Aijiren Hypersil BDS-C18 column (4.00 x 100 mm) and a diode array detector tuned at 214 nm and 235 nm was used. The acquisition method was isocratic, using a 60:40 mix of water:methanol as the mobile phase at a flow rate of 0.5 mL/min.