High-performance liquid chromatography was performed on a Shimadzu Prominence modular HPLC system comprising a LC-20A solvent pump, a DGU-20A5 degasser, a SIL-20A autosampler, a CBM-20A communication bus, a CTO-20A column oven, and a SPO-20A dual wavelength UV-vis detector operating at wavelengths of 220 and 250 nm. Reverse-phase HPLC was performed using an Alltech bonded silica column with a 5 μm pore size, an internal diameter of 4.6 mm and a length of 250 mm, with neat dichloromethane used as the mobile phase. Chromatograms where only one peak was detected are quoted at >99.9% purity.