DSC Thermogram Identification of Decoction Pieces of Moyao(Myrrha)of Different Medicinal Origins,Processed Products and Counterfeit Species
Objective:To establish the differential scanning calorimetry(DSC)for distinguishing natural Moyao(Myrrha),colloidal Moyao,processed Moyao and its counterfeit species.Methods:The samples of Moyao from different medicinal sources,processed products and counterfeit species were collected.By investigating the effect of heating range,heating rate,particle size and other factors on the DSC test con-ditions of Moyao,the differential thermal map of each sample of Moyao was scanned and analyzed by DSC under the optimized conditions.Results:The optimized DSC test conditions were as follows:the heating range of-25 to 550 ℃,the particle size of 100 mesh,and the heating rate of 50 ℃/min.The endothermic peak near 130 ℃ and the exothermic peak near 330 ℃ were the characteristic peaks of Moyao.The average temperature and enthalpy values of characteristic peaks at 130 ℃ and 330 ℃ of natural Moyao and colloid Moyao were significantly different,and the enthalpy values of natural Moyao were significantly lower than those of colloid Moyao.The counterfeit species[turpentine,Fengxiangzhi(Liquidambaris Resina)]could be clearly identified through comparing the characteristic peaks,which had no characteristic peak near 130 ℃ and 330 ℃.There was an endothermic peak at 10 ℃ for the counterfeit Fengxiangzhi,and an obvious exothermic peak near 150 ℃ for the counterfeit turpentine.The enthalpy values of characteristic peaks near 180 ℃ and 240 ℃ of natural Moyao processed with vinegar were lower than those of natural Moyao.Conclusions:DSC test could quickly and accurately distinguish natural Moyao,colloid Moyao,counterfeit Fengxiangzhi and turpentine,and could quickly distinguish Moyao processed with vinegar and Moyao.Endothermic peak at 130 ℃ and exothermic peak at 330 ℃ were the characteristic peaks of Moyao.
natural Moyao(Myrrha)colloidal Moyao(Myrrha)counterfeit speciesFengxiangzhi(Liquidambaris Resina)turpentinedifferential scanning calorimetryidentification study