Polarimeter

Genel Bakış

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 (−).

Prosedür

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

Sonuçlar

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 Başvuru ve Özet 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 Etiketler 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. Atla... 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 Bu koleksiyondaki videolar: Now Playing Polarimeter Organic Chemistry II 99.8K Görüntüleme Sayısı Cleaning Glassware Organic Chemistry II 123.1K Görüntüleme Sayısı Nucleophilic Substitution Organic Chemistry II 99.2K Görüntüleme Sayısı Reducing Agents Organic Chemistry II 42.7K Görüntüleme Sayısı Grignard Reaction Organic Chemistry II 148.7K Görüntüleme Sayısı n-Butyllithium Titration Organic Chemistry II 47.6K Görüntüleme Sayısı Dean-Stark Trap Organic Chemistry II 99.7K Görüntüleme Sayısı Ozonolysis of Alkenes Organic Chemistry II 66.7K Görüntüleme Sayısı Organocatalysis Organic Chemistry II 16.6K Görüntüleme Sayısı Palladium-Catalyzed Cross Coupling Organic Chemistry II 34.2K Görüntüleme Sayısı Solid Phase Synthesis Organic Chemistry II 40.8K Görüntüleme Sayısı Hydrogenation Organic Chemistry II 49.1K Görüntüleme Sayısı Polymerization Organic Chemistry II 93.6K Görüntüleme Sayısı Melting Point Organic Chemistry II 149.6K Görüntüleme Sayısı Infrared Spectroscopy Organic Chemistry II 213.8K Görüntüleme Sayısı Gizlilik Kullanım Şartları İlkeler Bize Ulaşın KÜTÜPHANEYE TAVSİYE ET JoVE HABER BÜLTENLERİ Araştırma JoVE Journal Yöntem Koleksiyonları JoVE Encyclopedia of Experiments Arşiv Eğitim JoVE Core JoVE Science Education JoVE Lab Manual JoVE Business JoVE Quiz JoVE Playlist Fakülte sitesi Yazarlar Genel Bakış Yayın Süreci Editör Kurulu Kapsam ve İlkeler Hakem Denetimi SSS Gönder Kütüphaneciler Genel Bakış Görüşler \| JoVE Abonelikler Erişim Kaynaklar Kütüphane Danışma Kurulu SSS JoVE Hakkında Genel Bakış Liderlik Blog JoVE Help Center JoVE Sitemap Telif Hakkı © 2020 MyJove Corporation. Tüm hakları saklıdır