Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China; Zhejiang Hisun Biomaterials Co., Ltd, Taizhou 318000, Zhejiang, China.
Zhejiang Hisun Biomaterials Co., Ltd, Taizhou 318000, Zhejiang, China.
Talanta. 2017 Mar 1;164:268-274. doi: 10.1016/j.talanta.2016.11.038. Epub 2016 Nov 20.
An analytical method has been proposed to quantify the D-lactide content in a lactide stereoisomeric mixture using combined gas chromatography and polarimetry (GC- polarimetry). As for a lactide stereoisomeric mixture, meso-lactide can be determined quantitatively using GC, but D- and L-lactides cannot be separated by the given GC system. The composition of a lactide stereoisomeric mixture is directly relative to its specific optical rotation. The specific optical rotations of neat L-lactide were obtained in different solutions, which were -266.3° and -298.8° in dichloromethane (DCM) and toluene solutions at 20°C, respectively. Therefore, for a lactide sample, the D-lactide content could be calculated based on the meso-lactide content obtained from GC and the specific optical rotations of the sample and neat L-lactide obtained from polarimetry. The effects of impurities and temperature on the test results were investigated, respectively. When the total content of impurities was not more than 1.0%, the absolute error for determining D-lactide content was less than 0.10% in DCM and toluene solutions. When the D-lactide content was calculated according to the specific optical rotation of neat L-lactide at 20°C, the absolute error caused by the variation in temperature of 20±15°C was not more than 0.2 and 0.7% in DCM and toluene solutions, respectively, and thus usually could be ignored in a DCM solution. When toluene was used as a solvent for the determination of D-lactide content, a temperature correction for specific optical rotations could be introduced and would ensure the accuracy of results. This method is applicable to the determination of D-lactide content in lactide stereoisomeric mixtures. The standard deviation (STDEV) of the measurements is less than 0.5%, indicating that the precision is suitable for this method.
已经提出了一种分析方法，使用气相色谱和偏振光法（GC-偏振光法）来定量测定丙交酯立体异构体混合物中的 D-丙交酯含量。对于丙交酯立体异构体混合物，使用 GC 可以定量测定内消旋丙交酯，但给定的 GC 系统无法分离 D-和 L-丙交酯。丙交酯立体异构体混合物的组成与其特定旋光性直接相关。在不同溶液中得到了纯 L-丙交酯的特定旋光率，在 20°C 下，在二氯甲烷（DCM）和甲苯溶液中分别为-266.3°和-298.8°。因此，对于丙交酯样品，可以根据从 GC 获得的内消旋丙交酯含量以及从偏振光获得的样品和纯 L-丙交酯的特定旋光率来计算 D-丙交酯含量。分别考察了杂质和温度对测试结果的影响。当杂质总含量不超过 1.0%时，在 DCM 和甲苯溶液中，测定 D-丙交酯含量的绝对误差小于 0.10%。当根据 20°C 下纯 L-丙交酯的特定旋光率计算 D-丙交酯含量时，在 DCM 和甲苯溶液中，温度变化 20±15°C 引起的绝对误差分别不超过 0.2%和 0.7%，通常可以忽略不计在 DCM 溶液中。当使用甲苯作为测定 D-丙交酯含量的溶剂时，可以引入特定旋光率的温度校正，以确保结果的准确性。该方法适用于丙交酯立体异构体混合物中 D-丙交酯含量的测定。测量的标准偏差（STDEV）小于 0.5%，表明该方法的精密度适合。
