基于^1H-NMR的聚桂醇成分分析

Component analysis of lauromacrogol based on ~1H-NMR

目的:利用1H-NMR测定聚桂醇中脂肪碳链的长度以及聚氧乙烯醚的聚合度,建立核磁共振定量方法测定聚桂醇的绝对含量。方法:采集1H-NMR谱图后,利用各个峰的积分值来计算聚桂醇中脂肪碳链的长度以及聚氧乙烯的聚合度;以1,4-二硝基苯为内标,通过比较δ3.4处样品定量峰与δ8.4处内标峰面积,计算聚桂醇含量。结果:聚桂醇样品中脂肪碳链的平均长度为12.4,聚氧乙烯醚的聚合度为9.4,以此计算聚桂醇的平均分子量为606.0 g·mol-1。以1,4-二硝基苯为内标物质,测定样品中聚桂醇的含量为97.5%,RSD=0.38%(n=3),与质量平衡法测定结果一致。结论:核磁共振法不仅可以用于聚桂醇结构信息的测定,而且可以快速、准确地测定聚桂醇的绝对含量,可以用于聚桂醇的成分分析。

Objective：To use1HNMR to characterize the average chain length of fatty alcohol and the degree of polymerization of polyethylene oxide in lauromacrogol and establish a quantitative NMR（ qNMR） method to characterize the content of lauromacrogol. Methods：After getting1HNMR spectrum,integration of each peak was used to calculate the average chain length of fatty alcohol and the degree of polymerization of polyethylene oxide; by comparing the peak area ratio of the sample（ δ 3. 4） and the internal standard 1,4dinitrobenzene（ δ 8. 4）,the content of lauromacrogol was calculated. Results：The average chain length of fatty alcohol was 12. 4 and the degree of polymerization of polyethylene oxide was 9. 4. Base on the results,the average molecular weight of lauromacrogol was606. 0 g·mol1. When 1,4dinitrobenzene was used as the internal reference standard,the calculated lauromacrogol content was 97. 5%. RSD was 0. 38%（ n = 3）. The result was consistent with the content calculated with mass balance method. Conclusion：1HNMR can give both the structure information and the content information of lauromacrogol quickly and correctly. This method can be used in lauromacrogol component analysis.