Analysis were conducted in HPLC Shimadzu LC-20A system
equipped with LC-20DA pump, manual injector with a fixed volume of 100 l L, CTO-20A column oven set at 40 ?C, running LC Solution software with UV–Vis detector model SPD-20A. The column was a Nova Pack C18 (CLC-ODS, 3 l m; 4.6 ? 250 mm).