2.4. Chromatographic conditions
Analytical separation was carried out on an Agilent 1100 HPLC
unit using a Supelco 516 C18 column (25 cm 4.6 mm, 5 lm) at
room temperature. The detector used was an UV–vis spectrophotometer
set at 225 nm and the volume of sample injected was
20 lL. The mobile phase used was methanol–ammonium acetate
buffer (0.02 M) (30:70, v/v); the flow rate was 1 mL/min.