糖类化合物旋光度测定实验的教学设计与实践

Teaching Design and Practice of the Experiment on Determination of Optical Rotation of Carbohydrate Compounds

摘要: 旋光度测定是表征糖类化合物立体结构、鉴别其种类并检验其纯度的重要物理化学方法，也是有机化学实验中的基础定量实训项目。本文在梳理旋光现象、比旋光度及旋光仪三分视场原理的基础上，依托WXG-4型圆盘旋光仪开展教学实践检验；同时简述自动数字旋光仪的工作机制与关键操作要点。本文对糖类化合物旋光度测定全流程提出规范化操作建议，内容涵盖仪器与试剂准备、标准溶液配制、光源预热与零点校正、旋光管装填、测定与读数、数据处理及仪器复位等关键环节；系统梳理归纳了系统误差与偶然误差的产生机制、影响规律与控制措施，建立典型异常现象的判断依据与处置方案。文中形成的标准化操作流程及配套教学设计，可为高等院校有机化学实验教学提供参考。

Abstract: Determination of optical rotation is an important physicochemical method for characterizing the stereostructure, identifying species, and verifying the purity of carbohydrate compounds, and also serves as a fundamental quantitative practical training item in organic chemistry experiments. On the basis of sorting out the optical rotation phenomenon, specific rotation and the three-field visual principle of polarimeters, this paper tests the aforementioned standard protocols via teaching practice using the WXG-4 disc polarimeter, and briefly discusses the working principle and critical control points of automatic digital polarimeters. Standardized operational recommendations are proposed for the whole workflow of carbohydrate optical‑rotation measurement, covering instrument and reagent preparation, standard‑solution preparation, light‑source preheating and zero‑point calibration, polarimeter‑tube filling, measurement and reading, data processing, and instrument resetting. Major sources, influencing rules, and control strategies of systematic and random errors are systematically summarized, together with criteria and troubleshooting protocols for common abnormal phenomena. The standardized workflow and teaching design presented in this paper can provide direct references for organic chemistry laboratory teaching in universities.