Chromatographic analysis was performed using a Shimadzu
(Kyoto, Japan) liquid chromatograph, with a vacuum degasser
(DGU-14A), quaternary pump LC-10AT, UVeVis detector (SPDM20A)
and manual injector with a 20 mL loop, employing LCSolution
software (CBM-20A). For the chromatographic separation
the column (4.6 mm 250 mm, 5 mm particle size) and guard
column (4.6 mm 12.5 mm) were of the type C18 reversed-phase
(Shimadzu, Kyoto, Japan).