高温凝胶色谱测定药用低密度聚乙烯的相对分子质量

Determination of Molecular Weight of Medicinal Low Density Polyethylene by High Temperature Gel Permeation Chromatography

目的建立准确测定药用低密度聚乙烯(聚乙烯瓶)相对分子质量信息的高温凝胶色谱方法。方法供试品于150℃下震荡溶解2 h,流动相为1,2,4,-三氯苯(含250 mg/L的抗氧剂BHT),色谱柱为高度交联的多孔聚苯乙烯/二乙烯基苯基柱,流速为1 mL/min,进样量为200μL,柱温为150℃,运行时间为35 min。考察溶解温度、溶解时间以及抗氧剂对相对分子质量测定的影响,并对方法进行优化,对不同的相对分子质量测定方法进行比较。结果对优化后的方法进行方法学考察,并采用相对法和绝对法计算相对分子质量。采用相对法计算出3批供试品的相对分子质量分别为236 327,238 832,240 631,相对分子质量分布分别为3.42,3.48,3.66;采用绝对法计算得到的相对分子质量分别为184 158,186 674,184 006,相对分子质量分布分别为4.30,4.25,4.24。结论该方法可准确测定药用低密度聚乙烯的相对分子质量信息。

The work aims to develop a high temperature GPC method for accurate determination of the molecular weight information of medicinal low density polyethylene(polyethylene bottle).The sample was vibrated and dissolved at 150℃for 2 h and the analysis was carried out on a highly crosslinked porous polystyrene/divinyl column which was eluted by a mobile phase of 250 mg/L antioxidant BHT in 1,2,4,-trichlorobenzene at a flow rate of 1 mL/min.The injection volume was 200μL,the column temperature was 150℃,and the running time was 35 min.The influence of the dissolution tem-perature,dissolution time and antioxidants on the molecular weight determination was discussed,and the methods were optimized to compare with different determination methods for molecular weight.The methodology was examined for the optimized method and relative and absolute methods were used to calculate the molecular weight.The relative molecular weight of the three batches which were calculated by the relative method were 236 327,238 832 and 240 631,respectively,and the polydispersity were 3.42,3.48 and 3.66;the relative molecular weights calculated by the absolute method were 184 158,186 674 and 184 006,respectively,and the polydispersity were 4.30,4.25 and 4.24.The method can be used to determine the molecular weight information of the medicinal low density polyethylene accurately.