Determination of the Purity of Sulfonamide Chemical Reference Materials by Differential Scanning Calorimetry

OBJECTIVE To determine the purity of sulfonamide chemical reference substances by differential scanning calorimetry(DSC).METHODS The purity of 7 sulfonamide chemical reference substances was determined by optimizing DSC parameters, carrier gas flow rate was 50 mL·min^-1, heating rate was 3 ℃·min^-1 and weighing amount was 1.3-2.0 mg.RESULTS The purity determined by DSC were 99.9%(sulfathiazole), 99.9%(sulfamethizole), 99.8%(sulfamethoxypridazine), 99.8%(sulfadiazine), 99.9%(sulfamethoxazole), 99.7%(sulfadoxine), and 99.9%(sulfadimidine), respectively. The results of purity determination by DSC method were basically consistent with those by mass balance method.CONCLUSION DSC is a simple, rapid method, and does not need standard substance. It provides a new method for the purity determination of sulfonamide chemical reference substances.