Figure 4: Chromatogram showing spiked solution of duloxetine hydrochloride and its impurities of method development trial 03 (5.5 mL orthophosphoric acid in 950 ml of water, pH adjusted to 3.2 with triethyl amine, and mixed with acetonitrile in a ratio (67:33 v/v), were used. Mobile phase-B contained acetonitrile).