A Perkin–Elmer (Analyst – TM 200, USA) HPLC, equipped with
UV–Visible detector, column oven, quaternary pumping system
and chromatography interface (Perkin–Elmer model 600), auto
injector (Villiers-1e-Bel, France) and IRIS Spectral Processing software
for peak identification and integration (Milford, MA, USA),
was used for peak purity determination.