TABLE 2.

HPLC Methods and Analyte Retention Times (min) of MXC and its Metabolites

Compound	Reverse-phase (C18) method	Chiral (AGP) column method
HPTE-glucuronide	6.4
OH-MXC-glucuronide	9.2
HPTE	13.3	12.6
(R)-OH-MXC	17.1	20.3
(S)-OH-MXC	17.1	30.4
MXC	20.9	39.2
MXC-olefin	21.8

Note. Separation on the C₁₈ column was carried out at 40°C. The mobile phase, 1 ml/min, was a linear gradient over 20 min of 30–90% acetonitrile in 10mM ammonium acetate/acetic acid buffer pH 4.6, followed by a gradient to 100% acetonitrile over 5 min before a return to starting conditions. Separation on the α-glycoprotein column was carried out at room temperature. The isocratic mobile phase, 0.9 ml/min, was 14% acetonitrile in 10mM ammonium acetate/acetic acid buffer pH 7.0.