4.2.9. 4-Aminophenol Level

A sample solution was prepared by accurately transferring paracetamol instant jelly equivalent to 400 mg of paracetamol into a 50 mL volumetric flask (concentration 8 mg/mL). Additionally, the sample solutions were prepared spiked with 25 µg/mL of 4-AP, that is, corresponding to the 50 ppm limit. For 4-aminophenol determination, the mobile phase consisted of sodium 1-butanesulfonate in a mixture of water and methanol and formic acid (15:85:0.4), and the flow rate was 2.0 mL/min. The detection wavelength was set to 272 nm, with a running time of 10 min per sample [44].