Preparation and Determination of Different Acetaminophen Samples by Thermal Analyzer (1) Sample 2: Raw powder of acetaminophen (sam- ple 1) was first heated to 180 °C by a differential scanning calorimetry (DSC-910, TA Instruments Inc., U.S.A.) at a heating rate of 3°C/min in an aluminum pan, maintained isothermally for 5 min, and then cooled to 25°C using a cooling system (DSC refrigerated cooling system, TA Instruments Inc., U.S.A.) at a cooling rate of 15°C/min to obtain the solidified melts. The process was carried out in an anhydrous nitrogen atmosphere.