1. Solutions of chlorophyll a were prepared in thirteen solvents and of chlorophyll b in five solvents by direct elution from sucrose adsorption columns. 2. Absorption spectra for each solvent are reported as measured spectrophoto-electrically in the visible region. 3. Spectra for the ultraviolet region to 2650 A were determined for solutions in ethyl ether. 4. A preparation of dried chlorophyll a was made which retained excellent spectroscopic properties. 5. The application of Kundt's rule to chlorophyll solutions is discussed, as well as certain relations of spectroscopic properties and solvents to analytical applications.

Effects of Solvent Upon Absorption Spectra of Chlorophylls A and B; Their Ultraviolet Absorption Spectra in Ether Solution

Treatment of moist cottonseed with ammonia prior to storage has been shown to reduce self-heating of the seed and the rate of formation of free fatty acids during storage. The color of oils obtained by solvent extraction from ammonia-treated cottonseed is considerably lighter than that of oils obtained from untreated cottonseed.

The storage of cottonseed

Light Absorption Spectrometry

Publisher Summary Physical methods that have been employed in vitamin and hormone studies include: visible- and ultraviolet-absorption spectrophotometry, photochemical techniques, colorimetry, fluorescence spectroscopy, fluorophotometry, infrared and Raman spectroscopy, x-ray diffraction studies, manometric techniques, polarography, and isotopic tracer methods. Of these techniques, some have had limited application and others are not universally regarded as physical. As this chapter is limited to methods that are both essentially physical, and of broad application in the vitamin and hormone field, only the following topics are included: visible- and ultraviolet-absorption spectrophotometry, colorimetry, fluorescence spectroscopy, and fluorophotometry. It has not been practicable to consider all aspects of these techniques. In discussing colorimetry, for example, it has been necessary to omit reference to the many chemical problems concerned with the devising of color reactions and of procedures for eliminating interfering substances. In deciding what material to include and what to exclude, preference has been given to the quantitative and physical aspects of the methods discussed.

and T R Hogness

Papers

Spectrometric Studies in Relation to Biology