Reverse phase-HPLC was performed using two Waters (Millipore) pumps 510; a Waters UV - visible detector 484; a Rheodyne injection valve 7725i; a Waters busSAT/IN module; a Waters pump control module; a reverse-phase C18 Nova-Pak column 4 µm (3.9 x 300 mm) thermostated at 37°C.
System control and data processing were performed using Millenium 32 chromatography manager software (Waters).
