Fig. 2
HPLC chromatogram of 4-aminophenol (10 μg/mL, tR: 1.728 min), paracetamol (30 μg/mL, tR: 3.413 min), para-hydroxy acetophenone (10 μg/mL, tR: 5.003 min), and Etoricoxib (30 μg/mL, tR: 7.275 min) using a linear gradient elution of solvent A (50 mM of potassium dihydrogen phosphate, adjusted to pH 4.0 with ortho-phosphoric acid) and solvent B (acetonitrile) as a mobile phase at a flow rate of 2.0 mL/min at 220 nm