title: Determination of D-lactide content in lactide stereoisomeric mixture using gas chromatography-polarimetry.
abstract: 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.
authors.affiliation: 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.
authors.forename: Lidong
authors.initials: L
authors.lastname: Feng
authors.affiliation: 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.
authors.forename: Xinchao
authors.initials: X
authors.lastname: Bian
authors.affiliation: Zhejiang Hisun Biomaterials Co., Ltd, Taizhou 318000, Zhejiang, China.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Chen
authors.affiliation: 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.
authors.forename: Sheng
authors.initials: S
authors.lastname: Xiang
authors.affiliation: 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.
authors.forename: Yanlong
authors.initials: Y
authors.lastname: Liu
authors.affiliation: 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.
authors.forename: Bin
authors.initials: B
authors.lastname: Sun
authors.affiliation: Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China.
authors.forename: Gao
authors.initials: G
authors.lastname: Li
authors.affiliation: Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin, China. Electronic address: xschen@ciac.ac.cn.
authors.forename: Xuesi
authors.initials: X
authors.lastname: Chen
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D004146:Dioxanes / Q000737:chemistry*; D055590:Electromagnetic Phenomena; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D013237:Stereoisomerism; D013696:Temperature
chemical_list: D004146:Dioxanes; D012997:Solvents; C091880:dilactide
keywords: D-lactide; Error; Gas chromatography; Meso-lactide; Polarimetry; Specific optical rotation