Abstract: An ultra performance liquid chromatography-photodiode array detector (UPLC-PDA) method was developed for the determination of ibuprofen and the solubilizer arginine in ibuprofen injection. 2,4-Dinitroflurobenzene (DNFB) was used as the precolumn derivatization reagent. The separation of ibuprofen and arginine derivative was performed on a BEH C18 column (50 mm×2.1 mm, 1.7 μm) with the mobile phase consisting of acetonitrile-0.05 mol/L potassium dihydrogen phosphate (pH 2.5) in a gradient elution mode at a flow rate of 0.4 mL/min. Ultraviolet absorption detection wavelengths were set at 357 nm for arginine derivative and 220 nm for ibuprofen. The column temperature was set at 30 ℃. Good linearities were obtained in the ranges of 2.0~100.5 mg/L for ibuprofen and 1.7~84.5 mg/L for arginine, both with the correlation coefficients (r) of 0.9997. The spiked recoveries were 99.8% and 99.6% with the relative standard deviations (RSDs) of 0.37% and 0.25% for ibuprofen and arginine, respectively. Their respective limits of quantification (LOQs) (S/N=10) were 0.1 ng and 0.2 ng, and the limits of detection (LODs) (S/N=3) were 0.03 ng and 0.05 ng. The results demonstrated that the proposed method is simple, accurate, reproducible and suitable for the quality control of ibuprofen injection.

Key words: arginine, ibuprofen, ibuprofen injection, pre-column derivatization, ultra performance liquid chromatography (UPLC)