Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

Improved Methods for the Purification of the Common Carotenoids, and the Quantitative Measurement of Their Absorption Spectra

Elmer S. Miller
Botanical Gazette
Vol. 96, No. 3 (Mar., 1935), pp. 447-467
Stable URL: http://www.jstor.org/stable/2471501
Page Count: 21
  • Read Online (Free)
  • Download ($19.00)
  • Subscribe ($19.50)
  • Cite this Item
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Improved Methods for the Purification of the Common Carotenoids, and the Quantitative Measurement of Their Absorption Spectra
Preview not available

Abstract

1. Simple improved methods for the purification of three of the common carotenoids have been developed. The methods of Tswett and Escher have been combined for the purification of the carotene isomers. The methods are described in detail. 2. A critical discussion of chromatographic analysis has been made. The necessary precautions are listed. 3. The quantitative absorption spectra of alpha and beta carotene, leaf xanthophyll, and lycopene were measured with an error of 2.0 per cent or less between 3950 and 5500 A. units. These spectra were measured by a spectro-photoelectric method which is accurate and precise. 4. Spectroscopic data show that certain tests of purity which have been considered accurate are only approximate. It is concluded that a critical examination of the absorption spectrum is the most reliable. 5. The absorption spectra of the carotenoids are employed as the basis for quantitative spectral analytical methods which have been applied to binary mixtures. 6. The preparative procedure includes and employs the precaution of excluding oxygen in the important steps of purification.

Page Thumbnails

  • Thumbnail: Page 
447
    447
  • Thumbnail: Page 
448
    448
  • Thumbnail: Page 
449
    449
  • Thumbnail: Page 
450
    450
  • Thumbnail: Page 
451
    451
  • Thumbnail: Page 
452
    452
  • Thumbnail: Page 
453
    453
  • Thumbnail: Page 
454
    454
  • Thumbnail: Page 
455
    455
  • Thumbnail: Page 
456
    456
  • Thumbnail: Page 
457
    457
  • Thumbnail: Page 
458
    458
  • Thumbnail: Page 
[459]
    [459]
  • Thumbnail: Page 
460
    460
  • Thumbnail: Page 
461
    461
  • Thumbnail: Page 
462
    462
  • Thumbnail: Page 
463
    463
  • Thumbnail: Page 
464
    464
  • Thumbnail: Page 
465
    465
  • Thumbnail: Page 
466
    466
  • Thumbnail: Page 
467
    467