Agilent 1200 series high performance auto sampler

LC analysis was carried out according to our previous study [14] . The LC system was composed of an Agilent 1100 series binary pump, an Agilent 1100 series variable wavelength detector, a column compartment, an Agilent 1260 Infinity high-performance degasser, and an Agilent 1200 series high-performance autosampler (Agilent Technologies Inc, USA). The equipment was fitted with a Luna phenyl-hexyl column (liquid layer thickness: 5 µm, 150 mm × 2.0 mm, Phenomenex, USA). Ultrapure water (solvent A) and a methanol/acetonitrile (6:1, v/v; solvent B) mixture served as the mobile phase (0.2 mL/min). The column temperature was 40 °C. The elution gradient program was as follows: 0-4 min, 20% of B; 4-10 min, linear gradient from 20 to 30% of B; 10-15 min, 30% of B; 15-40 min, linear gradient from 30 to 50% of B; 40-80 min, linear gradient from 50 to 60% of B; 80-90 min, linear gradient from 60 to 20% of B. Substrate determination was performed at 280 nm.
The erythro and threo peaks in the chromatogram of I were identified based on the LC analysis of erythro-rich I. I (erythro): retention time (RT): 24.9 min, I (threo): RT: 23.1 min, II: RT: 36.1 min, III: RT: 43.0 min.