The analytical separation
was performed on a Zorbax Eclipse XDB-C18
(100 mm 4.6 mm 1.8 lm) column (maintained at 35 C) connected
to a Zorbax Eclipse PAH guard column
(12.5 mm 4.6 mm 5 lm) (Agilent, Santa Clara, CA) using isocratic
elution with mobile phase acetonitrile/water 70:30 (v/v) at
a flow rate of 1.2 mL/min.