Polarimeter

Przegląd

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 (−).

Procedura

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

Wyniki

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 Wniosek i Podsumowanie 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 Tagi 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. Przejdź do... 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 Filmy z tej kolekcji: Now Playing Polarimeter Organic Chemistry II 98.2K Wyświetleń Cleaning Glassware Organic Chemistry II 121.9K Wyświetleń Nucleophilic Substitution Organic Chemistry II 98.5K Wyświetleń Reducing Agents Organic Chemistry II 42.5K Wyświetleń Grignard Reaction Organic Chemistry II 147.9K Wyświetleń n-Butyllithium Titration Organic Chemistry II 47.3K Wyświetleń Dean-Stark Trap Organic Chemistry II 97.5K Wyświetleń Ozonolysis of Alkenes Organic Chemistry II 66.3K Wyświetleń Organocatalysis Organic Chemistry II 16.5K Wyświetleń Palladium-Catalyzed Cross Coupling Organic Chemistry II 33.3K Wyświetleń Solid Phase Synthesis Organic Chemistry II 40.4K Wyświetleń Hydrogenation Organic Chemistry II 48.5K Wyświetleń Polymerization Organic Chemistry II 90.2K Wyświetleń Melting Point Organic Chemistry II 148.3K Wyświetleń Infrared Spectroscopy Organic Chemistry II 211.4K Wyświetleń Prywatność Warunki Korzystania Zasady Skontaktuj Się z Nami Poleć Bibliotece BIULETYNY JoVE Badania JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archiwum Edukacja JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Centrum Zasobów Akademickich Strona Wydziału Autorzy Przegląd Proces Publikacji Rada Redakcyjna Zakres i Zasady Recenzja ekspercka FAQ Prześlij Bibliotekarze Przegląd Referencje Subskrypcje Dostęp Zasoby Biblioteczna Rada Doradcza FAQ O JoVE Przegląd Kierownictwo Blog JoVE Help Center JoVE Sitemap Copyright © 2025 MyJoVE Corporation. Wszelkie prawa zastrzeżone