Table 1 Optimized conditions for HPLC

Mobile phase 1 (Bottle B)

Acetonitrile

Mobile phase 2 (Bottle D)

Phosphoric acid + hexylamine in 1 L water

Mode of mobile phase

Isocratic 7:93 B:D

Flow rate

1 mL/min

Degasser

Normal

Column temperature

35 ± 5 °C

Sampler temperature

OFF

Injection volume

5 μL

Mode of data acquisition

3D data collection

Scan range

190 to 400 nm

Resolution

1.2

Sampling rate

1.0

UV max detection for quantification

192 nm

Total run time

21 min