Optical rotation measurement is an important chemical analysis technique that is used to measure the degree of rotation of a substance on the vibration plane of polarized light. It is often used to study the molecular structure of natural products and organic compounds, as well as the reaction mechanism of certain organic reactions. This article starts from the basic principles of optical rotation measurement, introduces the definition and measurement method of optically active substances, and explains in detail the working principle and composition of the polarimeter. Subsequently, the specific operation of measuring optical rotation was explained based on the experimental procedures and instrument usage instructions. Finally, the influencing factors and related calculation methods of optical rotation measurement results are discussed, which provides theoretical and practical guidance for the application of this technology.
Optical rotation measurement is an important chemical analysis technique. It is often used to measure the degree of rotation of a substance on the vibration plane of polarized light. It can be used to study the molecular structure of natural products and organic compounds, as well as the reaction mechanism of certain organic reactions. This article will introduce and discuss optical rotation measurement from the basic principles, instrument use to experimental operations.
Fundamental
The measurement of optical rotation is based on the characteristic of optically active materials rotating the plane of polarized light vibration. Optically active substances cause the polarized light passing through them to undergo optical rotation. Optical rotation is a physical quantity that measures the degree of this rotation. Optically active substances include many organic compounds whose molecular structures are chiral, resulting in their optical activity. The instrument for measuring optical rotation is called a polarimeter. Its working principle is based on the fact that after polarized light passes through the optically active substance in the sample tube, the analyzer is adjusted to allow the light to pass through, thereby measuring the optical rotation.
Experimental operation
In the experiment, the liquid to be measured is first put into a sample tube and then measured by a polarimeter. The experimental steps include filling the sample tube, adjusting the analyzer, observing the brightness of the field of view, etc. The instrument required for the experiment is a WXG-4 disc polarimeter, and the reagents used include distilled water and tartaric acid solution or glucose solution of unknown concentration.
Experimental results are affected by many factors, including solution concentration, sample tube length, temperature and light source wavelength. By measuring the optical rotation, the specific optical rotation of a substance can be calculated, and then the optical purity and enantiomeric content of the sample can be analyzed. For the measurement of pure liquids, the specific optical rotation can be calculated directly from its density. Through experimental operations and calculation methods, the optical rotation of the sample can be accurately measured and relevant data can be obtained for analysis and research.
Optical rotation measurement is an important chemical analysis technology that can be used to study the molecular structure and reaction mechanism of substances. Through reasonable experimental operations and calculation methods, the optical rotation of the sample can be accurately measured and relevant data can be obtained for further analysis and research.
Future research can further expand the application fields of optical rotation measurement, especially in biomedicine, food safety and environmental monitoring. With the continuous development of science and technology, optical rotation measurement technology may be combined with other analytical methods to improve the accuracy and sensitivity of analysis. In addition, new optical polarization instruments and reagents can be developed to further simplify the operation process, reduce costs, improve measurement efficiency, and promote the promotion and application of this technology in practical applications.
