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Polarimeter

Обзор

Source: Vy M. Dong and Diane Le, Department of Chemistry, University of California, Irvine, CA

This experiment will demonstrate the use of a polarimeter, which is an instrument used to determine the optical rotation of a sample. Optical rotation is the degree to which a sample will rotate polarized light. Optically active samples will rotate the plane of light clockwise (dextrorotatory), designated as d or (+), or counterclockwise (levorotatory), designated as l or (−).

Процедура

1. Preparing the Polarimeter

Turn on instrument and let it warm up for 10 min.
Make sure instrument is set to "optical rotation" mode.
Prepare a blank sample in the polarimeter cell (1.5 mL total sample volume, 1 dm in length) containing only CHCl₃. Make sure there are no air bubbles present.
Place the blank cell in the holder and press "zero."

2. Preparation of Analyte Sample

Prepare a stock solution of 10

Результаты

Representative results for the measurement and calculation of specific rotation for Procedures 1-4.

Procedure Step	Reading on polarimeter
1.4	0.000
3.2	+0.563
4.1	[α]₂₅^D = +77° (c 0.73, CHCl₃) Log in or to access full content. Learn more about your institution’s access to JoVE content here Заявка и Краткое содержание In this experiment, we have demonstrated the principles behind the polarimeter and how to measure and calculate the specific rotation of an optically active compound. The polarimeter is an important instrument in the fine-chemical and pharmaceutical industries to assess the identity, purity, and quality of a compound. It is specifically used for the measurement of optical rotation of chiral compounds, which can be used to distinguish the identity of two enantiomers by confirming whether it is Log in or to access full content. Learn more about your institution’s access to JoVE content here Теги Polarimeter Purity Assessment Chemical Properties Enantiomers Mirror image Variants Biological Activities Pharmaceuticals Drug Thalidomide Principles Of Polarimetry Setup And Operation Applications Organic Compounds Stereocenters Chiral Compounds Mirror image Isomers Enantiomers Physical Properties Optics 1. Preparing the Polarimeter Turn on instrument and let it warm up for 10 min. Make sure instrument is set to "optical rotation" mode. Prepare a blank sample in the polarimeter cell (1.5 mL total sample volume, 1 dm in length) containing only CHCl₃. Make sure there are no air bubbles present. Place the blank cell in the holder and press "zero." 2. Preparation of Analyte Sample Prepare a stock solution of 10-15 mg of the chiral analyte in 1.5 mL CHCl₃. Note the exact amount of compound used. 3. Measuring Optical Rotation Fill the cell with 1.5 mL of the prepared stock solution containing the sample. Place the cell in the holder and press "measure." The machine readout will give the optical rotation value. Remember to record the temperature as well. 4. Calculation of Specific Rotation The specific rotation of a compound is defined by the following equation: where α is the optical rotation value given by the polarimeter, l is the cell pathlength in dm, and c is the concentration of the solution in g/mL. Перейти к... 0:00 Overview 0:49 Principles of Polarimetry 3:51 Initialization of the Polarimeter 4:24 Calibration and Measurement 5:23 Applications 6:52 Summary Видео из этой коллекции: Now Playing Polarimeter Organic Chemistry II 99.8K Просмотры Cleaning Glassware Organic Chemistry II 123.1K Просмотры Nucleophilic Substitution Organic Chemistry II 99.2K Просмотры Reducing Agents Organic Chemistry II 42.8K Просмотры Grignard Reaction Organic Chemistry II 148.8K Просмотры n-Butyllithium Titration Organic Chemistry II 47.6K Просмотры Dean-Stark Trap Organic Chemistry II 99.8K Просмотры Ozonolysis of Alkenes Organic Chemistry II 66.8K Просмотры Organocatalysis Organic Chemistry II 16.6K Просмотры Palladium-Catalyzed Cross Coupling Organic Chemistry II 34.2K Просмотры Solid Phase Synthesis Organic Chemistry II 40.8K Просмотры Hydrogenation Organic Chemistry II 49.2K Просмотры Polymerization Organic Chemistry II 93.7K Просмотры Melting Point Organic Chemistry II 149.6K Просмотры Infrared Spectroscopy Organic Chemistry II 214.0K Просмотры Конфиденциальность Условия эксплуатации Политика СВЯЖИТЕСЬ С НАМИ РЕКОМЕНДОВАТЬ БИБЛИОТЕКЕ НОВОСТИ JoVE Исследования JoVE Journal Подборки методов JoVE Encyclopedia of Experiments Архив Образование JoVE Core JoVE Science Education JoVE Lab Manual JoVE Business JoVE Quiz JoVE Playlist Сайт факультета АВТОРЫ Обзор Процесс публикации Редакционный совет Области применения и политики Рецензирование ЧАСТО ЗАДАВАЕМЫЕ ВОПРОСЫ Отправить Библиотекарь Обзор Отзывы Подписки Доступ ресурсы Библиотечный консультативный совет ЧАСТО ЗАДАВАЕМЫЕ ВОПРОСЫ О JoVE Обзор Руководство Блог JoVE Help Center JoVE Sitemap Авторские права © 2025 MyJoVE Corporation. Все права защищены